ρ

1. The 17th letter of the Greek alphabet, rho. 2. Symbol for population correlation coefficient; density.

R
R

Abbreviation or symbol for electrical resistance; radical (usually an alkyl or aryl group, e.g., ROH is an alcohol, RNH₂ an amine); Réaumur; respiration; respiratory exchange ratio; roentgen; the remainder of a chemical formula; the calculated unit representing vascular resistance in the cardiovascular system; arginine; arginyl; purine nucleoside.

℞
℞

Symbol for recipe in a prescription. See prescription (2) .

Rf
R_f, R_F

Symbol denoting movement of a substance in paper chromatography relative to the solvent front ( i.e., retardation factor); equal to the migration distance of a substance divided by the migration distance of the solvent front.

R
R

Abbreviation or symbol for (in italics) molar gas constant; one of two stereochemical designations in the Cahn, Ingold, and Prelog system; the third product formed in an enzyme-catalyzed reaction.

r
r

Abbreviation for roentgen; radius.

r
r

1. Symbol for correlation coefficient. 2. Abbreviation for racemic, occasionally used in naming compounds in place of the more common dl or (±), as “r-alanine” (more often as the prefix rac-).

Ra
Ra

Symbol for radium.

rabbeting
rabbeting (rab′et-ing)

Obsolete term for making congruous stepwise cuts on apposing bone surfaces for stability after impaction. [Fr. raboter, to plane]

rabid
rabid

Relating to or suffering from rabies. [L. rabidus, raving, mad]

rabies
rabies (ra′bez)

Highly fatal infectious disease that may affect all species of warm-blooded animals, including humans; transmitted by the bite of infected animals including dogs, cats, skunks, wolves, foxes, raccoons, and bats, and caused by a neurotropic species of Lyssavirus, a member of the family Rhabdoviridae, in the central nervous system and the salivary glands. The symptoms are characteristic of a profound disturbance of the nervous system, e.g., excitement, aggressiveness, and madness, followed by paralysis and death. Characteristic cytoplasmic inclusion bodies (Negri bodies) found in many of the neurons are an aid to rapid laboratory diagnosis. SYN: hydrophobia. [L. rage, fury, fr. rabio, to rave, to be mad]
dumb r. SYN: paralytic r..
furious r. the form or stage of r. in which the animal is markedly hyperactive, characterized by periods of agitation, thrashing, running, snapping, or biting.
paralytic r. a form or stage of r. marked by paralytic symptoms. SYN: dumb r..

rabiform
rabiform (ra′bi-form)

Resembling rabies.

rac- rac-

Prefix for racemic.

racefemine
racefemine (ra-se-fem′en)

Used as a uterine relaxant for relief of postpartum pain.

racemase
racemase (ra′se-mas)

An enzyme capable of catalyzing racemization, i.e., inversions of asymmetric groups; when more than one center of asymmetry is present, “epimerase” is used ( e.g., hydroxyproline, ribulose phosphate).

racemate
racemate (ra′se-mat)

A racemic compound, or the salt or ester of such a compound. SEE ALSO: racemic.

raceme
raceme (ra-sem′)

An optically inactive chemical compound. SEE ALSO: racemic.

racemic
racemic (r) (ra-se′mik, -sem′ik)

Denoting a mixture of optically active compounds that is itself optically inactive, being composed of an equal number of dextro- and levorotatory substances, which are separable. Those compounds internally compensated ( i.e., having an internal plane of symmetry) and therefore not separable into d and l (or + and −) forms, are termed “meso.”

racemization
racemization (ra′se-mi-za′shun, ras-mi-)

Partial conversion of one enantiomorph into another (as an l-amino acid to the corresponding d-amino acid) so that the specific optical rotation is decreased, or even reduced to zero, in the resulting mixture.

racemose
racemose (ras′e-mos)

Branching, with nodular terminations; resembling a bunch of grapes. [L. racemosus, full of clusters]

racephedrine hydrochloride
racephedrine hydrochloride (ras-e-fed′rin)

A sympathomimetic drug with peripheral effects similar to those of epinephrine and with the same actions and uses as ephedrine.

rachi- rachi-, rachio-

The spine. [G. rhachis, spine, backbone]

rachial
rachial (ra′ke-al)

SYN: spinal.

rachicentesis
rachicentesis (ra-ke-sen-te′sis)

SYN: lumbar puncture. [rachi- + G. kentesis, puncture]

rachidial
rachidial (ra-kid′e-al)

SYN: spinal.

rachidian
rachidian (ra-kid′e-an)

SYN: spinal.

rachilysis
rachilysis (ra-kil′i-sis)

Forcible correction of lateral curvature of the spine by lateral pressure against the convexity of the curve. [rachi- + G. lysis, a loosening]

rachio- rachio-

See rachi-.

rachiocentesis
rachiocentesis (ra-ke-o-sen-te′sis)

SYN: lumbar puncture. [rachio- + G. kentesis, puncture]

rachiochysis
rachiochysis (ra-ke-ok′i-sis)

A subarachnoid effusion of fluid in the spinal canal. [rachio- + G. chysis, a pouring out]

rachiopagus
rachiopagus (ra-ke-op′a-gus)

Conjoined twins united back to back with union of their spinal columns. See conjoined twins, under twin. SYN: rachipagus. [rachio- + G. pagos, something fixed]

rachioplegia
rachioplegia (ra′ke-o-ple′je-a)

SYN: spinal paralysis. [rachio- + G. plege, stroke]

rachiotome
rachiotome (ra′ke-o-tom)

A specially devised instrument for dividing the laminae of the vertebrae. SYN: rachitome. [rachio- + G. tome, incision]

rachiotomy
rachiotomy (ra-ke-ot′o-me)

SYN: laminotomy. [rachio- + G. tome, incision]

rachipagus
rachipagus (ra-kip′a-gus)

SYN: rachiopagus.

rachis
rachis, pl .rachidesrachises (ra′kis, ra′ki-dez, rak-)

SYN: vertebral column. [G. spine, backbone]

rachischisis
rachischisis (ra-kis′ki-sis)

1. Embryologic failure of fusion of vertebral arches and neural tube with consequent exposure of neural tissue at the surface; spina bifida cystica with myelocele or myeloschisis. 2. Spinal dysraphism. [G. rhachis, spine, + schisis, division]
r. partialis SYN: merorachischisis.
r. totalis SYN: holorachischisis.

rachitic
rachitic (ra-kit′ic)

Relating to or suffering from rickets (rachitis). SYN: rickety.

rachitis
rachitis (ra-ki′tis)

SYN: rickets. [G. rhachitis]
r. fetalis congenital rickets. SYN: r. intrauterina, r. uterina.
r. fetalis annularis congenital enlargement of the epiphyses of the long bones.
r. fetalis micromelica a congenital condition in which development of the long bones is deficient.
r. intrauterina, r. uterina SYN: r. fetalis.
r. tarda SYN: osteomalacia.

rachitism
rachitism (rak′i-tizm)

A rachitic state or tendency.

rachitogenic
rachitogenic (ra-kit-o-jen′ik)

Producing or causing rickets. [rachitis + G. genesis, production]

rachitome
rachitome (rak′i-tom)

SYN: rachiotome.

rad
rad

1. The unit for the dose absorbed from ionizing radiation, equivalent to 100 ergs per gram of tissue; 100 r. = 1 Gy. 2. Symbol for radian.

radarkymography
radarkymography (ra′dar-ki-mog′ra-fe)

An obsolete procedure involving the video tracking of heart motion by means of image intensification and closed circuit television during fluoroscopy; enabled cardiac motion to be measured by reproducible linear graphic tracing.

radectomy
radectomy (ra-dek′to-me)

SYN: root amputation. [L. radix, root, + G. ektome, excision]

Radford
Radford

Edward P., Jr., U.S. physiologist, *1922. See R. nomogram.

radiability
radiability (ra′de-a-bil′i-te)

The property of being radiable.

radiable
radiable (ra′de-a-bl)

Capable of being penetrated or examined by rays, especially by x-rays.

radiad
radiad (ra′de-ad)

In a direction toward the radial side.

radial
radial (ra′de-al)

1. Relating to the radius (bone of the forearm), to any structures named from it, or to the r. or lateral aspect of the upper limb as compared to the ulnar or medial aspect. SYN: radialis [TA] . 2. Relating to any radius. 3. Radiating; diverging in all directions from any given center. [L. radialis, fr. radius, ray, lateral bone of the forearm]

radialis
radialis (ra-de-a′lis) [TA]

SYN: radial (1) . [Mod. L.]

radian
radian (rad) (ra′de-an)

A supplementary SI unit of plane angle. [L. radius, ray]

radiant
radiant (ra′de-ant)

1. Giving out rays. 2. A point from which light radiates to the eye.

radiate
radiate (ra′de-at)

1. To spread out in all directions from a center. 2. To emit radiation. [L. radio, pp. -atus, to shine]

radiatio
radiatio, pl .radiationes (ra-de-a′she-o, -she-o′nez)

In neuroanatomy, a term applied to any one of the thalamocortical fiber systems that together compose the corona radiata of the cerebral hemisphere's white matter ( e.g., optic radiation, acoustic radiation, etc.). SYN: radiation (3) . [L.]
r. acustica [TA] SYN: acoustic radiation.
r. corporis callosi [TA] SYN: radiation of corpus callosum.
r. inferior thalami [TA] SYN: inferior thalamic peduncle.
r. optica [TA] SYN: optic radiation.
r. pyramidalis SYN: pyramidal radiation.
r. thalami anterior [TA] SYN: anterior thalamic radiation.
r. thalami centralis [TA] SYN: central thalamic radiation.
r. thalamica posterior [TA] SYN: posterior thalamic radiation.

radiation
radiation (ra′de-a′shun)

1. The act or condition of diverging in all directions from a center. 2. The sending forth of light, short radio waves, ultraviolet or x-rays, or any other rays for treatment or diagnosis or for other purpose. Cf.:irradiation (2) . 3. SYN: radiatio. 4. A ray. 5. Radiant energy or a radiant beam. [L. radiatio, fr. radius, ray, beam]
acoustic r. [TA] the fibers that pass from the medial geniculate body to the transverse temporal gyri of the cerebral cortex by way of the sublentiform part of the internal capsule. SYN: radiatio acustica [TA] .
afterloading r. method of administering r. that involves initial placement of local catheters with later installation of the r. source.
alpha r. an emission of a nucleus of high kinetic energy from the nucleus of an atom undergoing radioactive decay or fission.
annihilation r. the r. resulting when a positron from beta positive decay comes to rest. It encounters an electron, and they annihilate each other and convert their rest mass into two 0.51-MeV gamma rays emitted in exactly opposite directions. See pair production.
anterior thalamic r. [TA] r. formed by fibers interconnecting, via the anterior limb of the internal capsule, the anterior and medial thalamic nuclei and the cerebral cortex of the frontal lobe (excluding the precentral gyrus bordering on the central sulcus). SYN: radiatio thalami anterior [TA] .
background r. irradiation from environmental sources, including the earth's crust, the atmosphere, cosmic rays, and ingested radionuclides.Natural sources account for the largest amount of r. received by most persons each year (average annual dose, 3.00 mSv), with medical and occupational sources providing only a fraction (average less than 0.60 mSv). It is currently believed that radon, a gas produced by radium decay within crystal rock, constitutes the major source of background r. throughout many parts of the U.S. Radon buildup in inadequately ventilated homes may pose a long-term health hazard. The deleterious effects of background r., estimated as causing 1–6% of spontaneous genetic mutations, rise with dose.
beta r. radiant energy from a source of beta rays.
central thalamic r. [TA] r. formed by fibers interconnecting, through the posterior limb of the internal capsule, the ventral lateral, ventral posterolateral and posteromedial, lateral dorsal, and lateral posterior nuclei and the precentral gyrus and parietal lobe of the cerebral cortex. SYN: radiatio thalami centralis [TA] .
Cerenkov r. light given off by a transparent medium when a high-energy particle speeds through it at a velocity greater than that of light in that medium.
characteristic r. monochromatic r. that is produced when an electron is ejected from an atom and another takes its place by jumping from another shell; the energy of the emitted photon is the difference between that of the two shell positions. See photoelectric effect. SYN: characteristic emission.
r. of corpus callosum [TA] the spreading out of the fibers of the corpus callosum in the centrum semiovale of each cerebral hemisphere. SYN: radiatio corporis callosi [TA] .
corpuscular r. r. consisting of streams of subatomic particles such as protons, electrons, neutrons, etc.
electromagnetic r. r. originating in a varying electromagnetic field; e.g., long and short radio waves; light, visible and invisible; x-r. and gamma rays.
gamma r. ionizing electromagnetic r. resulting from nuclear processes, such as radioactive decay or fission.
geniculocalcarine r. SYN: optic r..
Gratiolet r. SYN: optic r..
hemibody r. a palliative cancer therapy involving r. to one-half of the body. [hemi- + body]
heterogeneous r. r. consisting of different frequencies, various energies, or a variety of particles. SEE ALSO: polychromatic r..
homogeneous r. r. consisting of a narrow band of frequencies, the same energy, or a single type of particle.
hyperfractionated r. smaller fractions of a dose of r. given more frequently than daily.
hypofractionated r. larger fractions of a dose of r. given less frequently than daily.
inferior thalamic r. [TA] SYN: inferior thalamic peduncle.
ionizing r. corpuscular ( e.g., neutrons, electrons) or electromagnetic ( e.g., gamma) r. of sufficient energy to ionize the irradiated material.
K-r. usually a very penetrating form of x-r. excited by cathode rays (high-speed electrons) impinging upon a metal anode such as tungsten; the energy of the r. is a function of the binding energy of the K-shell electrons of the metal anode.
L-r. an x-r. of slight penetrating power excited by cathode rays (high-speed electrons) impinging on a metal anode; the energy of the r. is a function of the binding energy of the L-shell electrons of the metal anode.
monochromatic r. light rays or ionizing r. of a very narrow band of wavelengths (ideally, of a single wavelength). Cf.:photopeak, characteristic r..
neutron r. an emission of neutrons from the nucleus of an atom by decay or fission.
occipitothalamic r. SYN: optic r..
optic r. [TA] the massive, fanlike fiber system passing from the lateral geniculate body of the thalamus to the visual cortex (striate or calcarine cortex, area 17 of Brodmann); the fibers follow the retrolenticular and sublenticular limbs of the internal capsule into the corona radiata but they curve back along the lateral wall of the temporal and occipital horns of the lateral ventricle to the striate cortex on the medial surface and pole of the occipital lobe. SYN: radiatio optica [TA] , geniculocalcarine r., geniculocalcarine tract, Gratiolet fibers, Gratiolet r., occipitothalamic r., Wernicke r..
polychromatic r. r. containing gamma rays, under ray of many different energies; in diagnostic radiology, typically bremsstrahlung.
posterior thalamic r. [TA] r. formed by fibers interconnecting through the retrolenticular part of the posterior limb of the internal capsule, the pulvinar complex and lateral geniculate nucleus, and the posterior parietal and occipital lobes of the cerebral cortex. SYN: radiatio thalamica posterior [TA] .
primary r. an incident x-ray beam.
pyramidal r. corticospinal fibers passing from the cortex into the pyramid. SYN: radiatio pyramidalis.
scattered r. secondary r. emitted from the interaction of x-rays with matter; generally lower in energy, with a directional distribution that depends on the energy of the incident r.. SYN: secondary r..
secondary r. SYN: scattered r..
Wernicke r. SYN: optic r..

radical
radical (rad′i-kal)

1. In chemistry, a group of elements or atoms usually passing intact from one compound to another, but usually incapable of prolonged existence in a free state ( e.g., methyl, CH₃); in chemical formulas, a r. is often distinguished by being enclosed in parentheses or brackets. 2. Thorough or extensive; relating or directed to the extirpation of the root or cause of a morbid process; e.g., a r. operation. 3. Denoting treatment by extreme, drastic, or innovative, as opposed to conservative, measures. 4. SYN: free r.. [L. radix (radic-), root]
acid r. a r. formed from an acid by loss of one or more hydrogen ions; e.g., SO₄⁻, NO₃⁻.
color r. SYN: chromophore.
free r. a r. in its (usually transient) uncombined state; an atom or atom group carrying an unpaired electron and no charge; e.g., hydroxyl and methyl Free radicals may be involved as short-lived, highly active intermediates in various reactions in living tissue, notably in photosynthesis. The free r. nitric oxide, NO, plays an important role in vasodilation. SYN: r. (4) .Free radicals occur naturally within the body as a result of metabolic processes and can also be introduced from without (through smoking, inhaling environmental pollutants, or exposure to UV radiation). They interact readily with nearby molecules and may cause cellular damage, including genetic alterations. It has been theorized that they are involved in plaque formation in atherosclerosis, in cancer, and in degenerative disorders such as Alzheimer dementia and parkinsonism. Natural enzymes such as superoxide dismutase and peroxidase are thought to counteract free radicals, and there is evidence that many nutrients, including vitamins C and E and β-carotene, also exert an antioxidant effect. see also antioxidant.
oxygen-derived free radicals an atom or atom group having an unpaired electron on an oxygen atom, typically derived from molecular oxygen. For example, one-electron reduction of O₂ produces the superoxide r., O₂·; other examples include the hydroperoxyl r. (HOO·), the hydroxyl r. (HO·), and nitric oxide (NO·). These apparently have a role in reprofusion injury.

radices
radices (ra-di′sez)

Plural of radix.

radicle
radicle (rad′i-kl)

A rootlet or structure resembling one, as the r. of a vein, a minute veinlet joining with others to form a vein, or the r. of a nerve, a nerve fiber that joins others to form a nerve. [L. radicula, dim. of radix, root]

radicotomy
radicotomy (rad-i-kot′o-me)

SYN: rhizotomy. [L. radix (radic-), root, + G. tome, incision]

radicul- radicul-

See radiculo-.

radicula
radicula (ra-dik′u-la)

A spinal nerve root. [L. dim of radix, root]

radiculalgia
radiculalgia (ra-dik′u-lal′je-a)

Neuralgia due to irritation of the sensory root of a spinal nerve. [radicul- + G. algos, pain]

radicular
radicular (ra-dik′u-lar)

1. Relating to a radicle. 2. Pertaining to the root of a tooth.

radiculectomy
radiculectomy (ra-dik′u-lek′to-me)

SYN: rhizotomy. [radicul- + G. ektome, excision]

radiculitis
radiculitis (ra-dik-u-li′tis)

SYN: radiculopathy. [radicul- + G. -itis, inflammation]
acute brachial r. SYN: neuralgic amyotrophy.

radiculo- radiculo-, radicul-

Radicle; radicular. [L. radicula, radicle, dim. of radix, root]

radiculoganglionitis
radiculoganglionitis (ra-dik′u-lo-gang′gle-o-ni′tis)

Involvement of roots and ganglia.

radiculomeningomyelitis
radiculomeningomyelitis (ra-dik′u-lo-me-ning′go-mi-e-li′tis)

SYN: rhizomeningomyelitis.

radiculomyelopathy
radiculomyelopathy (ra-dik′u-lo-mi′e-lop′a-the)

SYN: myeloradiculopathy.

radiculoneuropathy
radiculoneuropathy (ra-dik′u-lo-noo-rop′a-the)

Disease of the spinal nerve roots and nerves.

radiculopathy
radiculopathy (ra-dik′u-lop′a-the)

Disorder of the spinal nerve roots. SYN: radiculitis. [radiculo- + G. pathos, suffering]
diabetic thoracic r. a type of diabetic neuropathy that affects primarily elderly patients with diabetes mellitus; clinically characterized by thoracic or abdominal pain, mainly anterior, but sometimes with radiation around the trunk from the midline; usually unilateral; may extend over several segments; probably due to ischemic injury of two or more contiguous roots; one type of diabetic polyradiculopathy.

radiectomy
radiectomy (ra-de-ek′to-me)

SYN: root amputation. [L. radix, root, + G. ektome, excision]

radiferous
radiferous (ra-dif′er-us)

Containing radium.

radii
radii (ra′de-i)

Plural of radius. [L.]

radio- radio-

1. Radiation, chiefly (in medicine) gamma or x-ray. 2. SYN: radioactive. 3. SYN: radius. [L. radius, ray]

radioactive
radioactive (ra′de-o-ak′tiv)

Possessing radioactivity. SYN: radio- (2) .

radioactive cow
radioactive cow

Colloquialism for radionuclide generator. SEE ALSO: cow.

radioactivity
radioactivity (ra′de-o-ak-tiv′i-te)

The property of some atomic nuclei of spontaneously emitting gamma rays or subatomic particles (α and β rays) by the process of nuclear disintegration and measured in disintegrations per second (dps). One dps is equal to 1 becquerel, and 3.7 × 10¹⁰ dps equals 1 curie.
artificial r. the r. of isotopes created by the bombardment of naturally occurring isotopes by subatomic particles, or high levels of x- or gamma radiation. SYN: induced r..
induced r. SYN: artificial r..

radioautogram
radioautogram (ra′de-o-aw′to-gram)

Older term for autoradiograph.

radioautography
radioautography (ra′de-o-aw-tog′ra-fe)

SYN: autoradiography.

radiobicipital
radiobicipital (ra′de-o-bi-sip′i-tal)

Relating to the radius and the biceps muscle.

radiobiology
radiobiology (ra′de-o-bi-ol′o-je)

The study of the biologic effects of ionizing radiation upon living tissue. Cf. radiopathology.

radiocalcium
radiocalcium (ra′de-o-kal′se-um)

A radioisotope of calcium, particularly calcium-45.

radiocarbon
radiocarbon (ra′de-o-kar′bon)

A radioactive isotope of carbon; e.g., ¹⁴C.

radiocardiogram
radiocardiogram (ra′de-o-kar′de-o-gram)

A graphic record of the concentration of injected radioisotope within the cardiac chambers.

radiocardiography
radiocardiography (ra′de-o-kar-de-og′ra-fe)

The technique of recording or interpreting radiocardiograms.

radiocarpal
radiocarpal (ra′de-o-kar′pal)

1. Relating to the radius and the bones of the carpus. 2. On the radial or lateral side of the carpus.

radiocephalpelvimetry
radiocephalpelvimetry (ra′de-o-sef-al-pel-vim′e-tre)

SYN: pelvimetry. [radio- + cephal- + pelvimetry]

radiochemistry
radiochemistry (ra′de-o-kem′is-tre)

1. The science of using radionuclides to synthesize labeled compounds for biochemical or biologic research, or radiopharmaceuticals for clinical diagnostic studies. 2. The study of methods of labeling compounds with radionuclides. 3. The science concerned with the effects of ionizing or nuclear radiation on chemical reactions or materials.

radiochlorine
radiochlorine (ra′de-o-klor′en)

A radioactive isotope of chlorine, e.g., ³⁶Cl.

radiocholangiography
radiocholangiography (ra′de-o-ko-lan-je-og′ra-fe)

Cholangiography obtained by the intravenous administration of an excreted radiopharmaceutical. [radio- + cholangiography]

radiocholecystography
radiocholecystography (ra′de-o-ko-le-sis-tog′ra-fe)

Visualization of the gallbladder by scintigraphic means using a radiopharmaceutical such as technetium-99m–labeled iminodiacetic acid derivative. [radio- + cholecysoghraphy]

radiocineangiocardiography
radiocineangiocardiography (ra′de-o-sin′e-an′je-o-kar-de-og′ra-fe)

Scintigraphic motion picture of the passage of a radiopharmaceutical through the heart and great vessels. [radio- + cineangiography]

radiocineangiography
radiocineangiography (ra′de-o-sin′e-an′je-og′ra-fe)

Scintigraphic motion pictures of the passage of a radiopharmaceutical through blood vessels.

radiocinematography
radiocinematography (ra′de-o-si-ne-ma-tog′ra-fe)

Taking a motion picture of the movements of organs or other structures as revealed by x-ray fluoroscopic examination. [radio- + G. kinema, motion, + grapho, to write]

radiocobalt
radiocobalt (ra′de-o-ko′balt)

A radioactive isotope of cobalt; e.g., ⁶⁰Co.

radiocurable
radiocurable (ra′de-o-kur′a-bl)

Curable by irradiation therapy.

radiodense
radiodense (ra′de-o-dens)

SYN: radiopaque.

radiodensity
radiodensity (ra′de-o-den′si-te)

SYN: radiopacity.

radiodermatitis
radiodermatitis (ra′de-o-der-ma-ti′tis)

Dermatitis due to exposure to x-rays or gamma rays causing ionization of tissue water with acute changes resembling thermal injury.

radiodiagnosis
radiodiagnosis (ra′de-o-di-ag-no′sis)

Diagnosis using x-rays; or, more broadly, diagnostic imaging, including radiology, ultrasound, and magnetic resonance.

radiodigital
radiodigital (ra′de-o-dij′i-tal)

Relating to the fingers on the radial or lateral side of the hand.

radioelectrophysiologram
radioelectrophysiologram (ra′de-o-e-lek′tro-fiz-e-ol′o-gram)

The record obtained by means of the radioelectrophysiolograph.

radioelectrophysiolograph
radioelectrophysiolograph (ra′de-o-e-lek′tro-fiz-e-ol′o-graf)

Formerly, an apparatus carried by a mobile individual by means of which changes in electrical potential from the brain or heart can be picked up and radio-transmitted to an electroencephalograph or an electrocardiograph. See telemeter.

radioelectrophysiolography
radioelectrophysiolography (ra′de-o-e-lek′tro-fiz′e-o-log′ra-fe)

Formerly, recording the changes in the electrical potential of the brain or heart by means of the radioelectrophysiolograph. See telemetry.

radioelement
radioelement (ra′de-o-el′e-ment)

Any element possessing radioactivity.

radioepithelitis
radioepithelitis (ra′de-o-ep′i-the-li′tis)

Destructive changes in epithelium produced by ionizing radiation.

radiofrequency
radiofrequency (ra′de-o-fre′kwen-se)

1. Radiant energy of a certain frequency range; e.g., radio and television employ radiant energy having a frequency between 10⁵–10¹¹ Hz, while diagnostic x-rays have a frequency in the range of 3 × 10¹⁸ Hz. 2. In magnetic resonance imaging, the energy applied to switch or create a gradient in the magnetic field.

radiogallium
radiogallium (ra′de-o-gal′e-um)

Gallium that is radioactive. See gallium-67, gallium-68.

radiogenesis
radiogenesis (ra′de-o-jen′e-sis)

The formation or production of radioactivity resulting from radioactive transformation or disintegration of radioactive substances. [radio- + G. genesis, production]

radiogenic
radiogenic (ra′de-o-jen′ik)

1. Producing rays of any sort, especially electromagnetic rays. 2. Caused by x- or gamma rays.

radiogenics
radiogenics (ra′de-o-jen′iks)

The science of radiation.

radiogold colloid
radiogold colloid (ra′de-o-gold kol′oyd)

A radioactive isotope of gold emitting negative beta particles and gamma radiation, with a half-life of 2.7 days; formerly used for irradiation of closed serous cavities in the palliative treatment of ascites and pleural effusion due to metastatic malignancies, and for liver scans. SYN: ¹⁹⁸Au colloid, colloidal radioactive gold.

radiogram
radiogram (ra′de-o-gram)

Obsolete term for radiograph. [radio- + G. gramma, something written]

radiograph
radiograph (ra′de-o-graf)

A negative image on photographic film made by exposure to x-rays or gamma rays that have passed through matter or tissue. SYN: roentgenogram, roentgenograph, x-ray (3) . [radio- + G. grapho, to write]
bitewing r. intraoral dental film adapted to show the coronal portion and cervical third of the root of the teeth in near occlusion; especially useful in detecting interproximal caries and determining alveolar septal height.
cephalometric r. a radiographic view of the jaws and skull permitting measurement. SYN: cephalogram.
decubitus r. a r. of a recumbent subject on his side, made in the frontal projection with a horizontal x-ray beam. SYN: lateral decubitus r..
lateral decubitus r. SYN: decubitus r..
lateral oblique r. a radiographic view of the mandible, revealing one side of the mandible from symphysis to condyle by displacing the other side upwards.
lateral ramus r. a radiographic view of the mandibular ramus and condyle.
lateral skull r. a true lateral projection r. of facial bones and calvarium, showing bone structures and air-containing passages.
maxillary sinus r. a radiographic frontal view of the maxillary sinuses, orbits, nasal structures and zygomas; permits direct comparison of the sides. SYN: Waters view r..
occlusal r. intraoral section film positioned on the occlusal plane and used in visualizing entire sections of the jaw; especially useful in exploring calcifications of the sublingual salivary glands.
panoramic r. a radiographic view of the maxillae and mandible extending from the left to the right glenoid fossae.
periapical r. a r. demonstrating tooth apices and surrounding structures in a particular intraoral area.
scout r. SYN: scout film.
submental vertex r. SYN: submentovertex r..
submentovertex r. a radiographic projection showing the base of the skull, positions of the mandibular condyles, and zygomatic arches. SYN: base view, submental vertex r..
Towne projection r. See Towne projection.
transcranial r. a radiographic view of the temporomandibular articulation.
Trendelenburg r. r. of a subject tilted head downwards, usually in the decubitus position; used to detect small pleural effusions.
Waters view r. SYN: maxillary sinus r..

radiographer
radiographer (ra-de-og′ra-fer)

A technician trained to position patients and take radiographs or perform other radiodiagnostic procedures.

radiography
radiography (ra′de-og′ra-fe)

Examination of any part of the body for diagnostic purposes by means of x-rays with the record of the findings usually impressed upon a photographic film. SYN: roentgenography.
advanced multiple-beam equalization r. (AMBER) a variant of scanning equalization r. using several x-ray beams.
air-gap r. chest r. with a space (at least 10 inches) between the subject and film. Instead of using a grid, this method uses the geometry and x-ray absorption by the air to remove scattered radiation.
bedside r. SYN: portable r..
computed r. (CR) converting transmitted x-rays into light, using a solid-state imaging device such as a photostimulable phosphor plate, and recovering and processing the image using a digital computer; the image may then be printed on film or displayed on a computer screen.
digital r. (DR) direct conversion of transmitted x-rays into a digital image using an array of solid-state detectors such as amorphous selenium or silicon, with computer processing and display of the image. See DSA.
electron r. radiographic imaging in which x-radiation incident on the receptor is converted to a latent charge image and subsequently recovered by a special printing process; advantages include wider latitude of exposure and greater sensitivity than conventional film-screen combinations. See xeroradiography, phosphor plate.
filmless r. electronic acquisition and distribution of radiographic images, eliminating the handling and storage of film. SEE ALSO: PACS.
magnification r. r. using a microfocal x-ray tube and increased subject-film distance to provide geometric magnification of the subject without unacceptable loss of sharpness and resolution.
mucosal relief r. radiographic technique showing fine detail of gastrointestinal mucosa after coating it with a barium suspension and distending the organ with air or gas released from an ingested powder.
portable r. making a radiographic film of a patient confined to bed by taking a movable x-ray machine to the room. SYN: bedside r..
scanning equalization r. an electronically enhanced method of r. in which a narrow x-ray beam is scanned over the patient while its attenuation is measured, providing feedback to modulate beam intensity in order to equalize regional x-ray film exposure.
sectional r. SYN: tomography.
serial r. making several x-ray exposures of a single region over a period of time, as in angiography.
spot-film r. an x-ray of a localized region, usually under study by fluoroscopy.

radiohumeral
radiohumeral (ra′de-o-hu′mer-al)

Relating to the radius and the humerus; denoting the articulation between them.

radioimmunity
radioimmunity (ra′de-o-i-mu′ni-te)

Lessened sensitivity to radiation.

radioimmunoassay
radioimmunoassay (RIA) (ra′de-o-im′u-no-as′sa)

An immunologic (immunochemical) procedure that uses the competition between radioisotope-labeled antigen or other substance and unlabeled antigen for antiserums, resulting in quantitation of the unlabeled antigen; any method for detecting or quantitating antigens or antibodies using radiolabeled reactants. Minute quantities of enzymes, hormones, or other substances can be assayed.

radioimmunodiffusion
radioimmunodiffusion (ra′de-o-im′u-no-di-fu′zhun)

A method for the study of antigen-antibody reactions by gel diffusion using radioisotope-labeled antigen or antibody.

radioimmunoelectrophoresis
radioimmunoelectrophoresis (ra′de-o-im′u-no-e-lek′tro-fo-re′sis)

Immunoelectrophoresis in which the antigen or antibody is labeled with a radioisotope; e.g., in testing for insulin-binding antibodies by treating the test serum with radioactive iodine-labeled insulin, subjecting the mixture (antigen) to electrophoresis, precipitating the separated immunoglobulins with immunoglobulin-specific antiserum, and, then, with radiosensitive film (autoradiography), testing for bound insulin in the precipitates.

radioimmunoprecipitation
radioimmunoprecipitation (RIP) (ra′de-o-im′u-no-pre-sip-i-ta′shun)

Immunoprecipitation utilizing a radioisotope-labeled antibody or antigen.

radioiodinated
radioiodinated (ra′de-o-i′o-din-a-ted)

Treated or combined with radioiodine.

radioiodine
radioiodine (ra′de-o-i′o-din)

A radioactive isotope of iodine; e.g., ¹²³I.

radioiron
radioiron (ra′de-o-i′ern)

A radioactive isotope of iron; e.g., ⁵⁹Fe.

radioisotope
radioisotope (ra′de-o-i′so-top)

An isotope that changes to a more stable state by emitting radiation.

radiolabeled
radiolabeled (ra′de-o-la′bld)

See tag (1) .

radiolead
radiolead (ra′de-o-led′)

A radioactive isotope of lead, usually 210 Pb. See lead.

radiolesion
radiolesion (ra′de-o-le′zhun)

A lesion produced by ionizing radiation.

radioligand
radioligand (ra′de-o-lig′and)

A molecule with a radionuclide tracer attached; usually used for radioimmunoassay procedures. [radio- + L. ligandus, that which is to be bound, fr. ligo, to bind]

radiologic
radiologic, radiological (ra-de-o-log′ik, -loj′i-kal)

Pertaining to radiology.

radiologist
radiologist (ra-de-ol′o-jist)

A physician trained in the diagnostic and/or therapeutic use of x-rays and radionuclides, radiation physics and biology; a diagnostic r. would also be trained in diagnostic ultrasound and magnetic resonance imaging and applicable physics.

radiology
radiology (ra-de-ol′o-je)

1. The science of high-energy radiation and of the sources and the chemical, physical, and biologic effects of such radiation; the term usually refers to the diagnosis and treatment of disease. 2. The scientific discipline of medical imaging using ionizing radiation, radionuclides, nuclear magnetic resonance, and ultrasound. SYN: diagnostic r.. [radio- + G. logos, study]
cardiovascular r. the clinical subspecialty of r. concerned with diagnosis and treatment of diseases of the vascular system.
chest r. the clinical subspecialty concerned with the diagnostic r. of diseases of the thorax, especially of the heart and lungs.
diagnostic r. SYN: r. (2) .
interventional r. the clinical subspecialty that uses fluoroscopy, CT, and ultrasound to guide percutaneous procedures such as performing biopsies, draining fluids, inserting catheters, or dilating or stenting narrowed ducts or vessels.
pediatric r. the clinical subspecialty concerned with the radiologic manifestations of diseases of children.
therapeutic r. SYN: radiation oncology.

radiolucency
radiolucency (ra-de-o-loo′sen-se)

A region of a radiograph showing increased exposure, either because of greater transradiancy of the corresponding portion of the subject or because of inhomogeneity in the source of radiation, such as off-center positioning.

radiolucent
radiolucent (ra-de-o-loo′sent)

Relatively penetrable by x-rays or other forms of radiation. Cf.:radiopaque. [radio- + L. lucens, shining]

radiolus
radiolus (ra-de′o-lus)

A probe or sound. [L. dim. of radius, spoke]

radiometer
radiometer (ra-de-om′e-ter)

A device for determining the penetrative power of x-rays. SYN: roentgenometer. [radio- + G. metron, measure]

radiomicrometer
radiomicrometer (ra′de-o-mi-krom′e-ter)

A sensitive thermopile designed for the measurement of minute changes in radiant energy.

radiomimetic
radiomimetic (ra′de-o-mi-met′ik)

Imitating the biologic effects of radiation, as in the case of chemicals such as nitrogen mustards. [radio- + G. mimetikos, imitative]

radiomuscular
radiomuscular (ra′de-o-mus′ku-lar)

Relating to the radius and the neighboring muscles; denoting certain nerves and muscular branches of the radial artery.

radionecrosis
radionecrosis (ra′de-o-ne-kro′sis)

Necrosis due to radiation; e.g., after excessive exposure to x- or gamma rays. See radiation burn.

radioneuritis
radioneuritis (ra′de-o-noo-ri′tis)

Neuritis caused by prolonged or repeated exposure to x-rays or radium.

radionitrogen
radionitrogen (ra′de-o-ni′tro-jen)

A radioactive isotope of nitrogen; e.g., ¹³N.

radionuclide
radionuclide (ra′de-o-noo′klid)

An isotope of artificial or natural origin that exhibits radioactivity.

radiopacity
radiopacity (ra′de-o-pas′i-te)

The x-ray shadow of a radiopaque object. SYN: radiodensity.

radiopalmar
radiopalmar (ra′de-o-pal′mar)

Relating to the radial or lateral side of the palm.

radiopaque
radiopaque (ra-de-o-pak′)

Exhibiting relative opacity to, or impenetrability by, x-rays or any other form of radiation. Cf.:radiolucent. SYN: radiodense. [radio- + Fr. opaque fr. L. opacus, shady]

radiopathology
radiopathology (ra′de-o-path-ol′o-je)

A branch of radiology or pathology concerned with the effects of radiation on cells and tissues. Cf.:radiobiology.

radiopelvimetry
radiopelvimetry (ra′de-o-pel-vim′e-tre)

Radiographic measurement of the pelvis. See pelvimetry.

radiopharmaceutical
radiopharmaceutical (ra′de-o-far-ma-soo′ti-kal)

A radioactive chemical or pharmaceutic preparation, labeled with a radionuclide in tracer or therapeutic concentration, used as a diagnostic or therapeutic agent.

radiophobia
radiophobia (ra′de-o-fo′be-a)

Morbid fear of radiation, as from x-rays or nuclear energy. [radio- + G. phobos, fear]

radiophosphorus
radiophosphorus (ra′de-o-fos′for-us)

A radioactive isotope of phosphorus; e.g., ³²P.

radiopill
radiopill (ra′de-o-pil)

SYN: radiotelemetering capsule.

radiopotassium
radiopotassium (ra′de-o-po-tas′e-um)

A radioactive isotope of potassium; e.g., ⁴⁰K.

radioprotectant
radioprotectant (ra′de-o-pro-tek′tant)

Substance that prevents or lessens the effects of radiation.

radioreceptor
radioreceptor (ra′de-o-re-sep′ter)

1. A receptor that normally responds to radiant energy such as light or heat. 2. A receptor used as a binding agent for unlabeled and radiolabeled analyte in a type of competitive binding assay called r. assay.

radioresistant
radioresistant (ra′de-o-re-zis′tant)

Indicates cells or tissues that are less affected than average mammalian cells on exposure to radiation; when applied to neoplasms, indicates less susceptibility to damage from therapeutic radiation than the surrounding host tissues.

radioscopy
radioscopy (ra′de-os′ko-pe)

Obsolete term for fluoroscopy. [radio- + G. skopeo, to view]

radiosensitive
radiosensitive (ra′de-o-sen′si-tiv)

Readily affected by radiation. Cf.:radioresistant.

radiosensitivity
radiosensitivity (ra′de-o-sen-si-tiv′i-te)

The condition of being readily affected by radiant energy.

radiosensitization
radiosensitization (ra′de-o-sen-si-ti-za′shun)

The use of chemotherapy or other agents that increase the sensitivity of tissue to the effects or radiation therapy, usually by inhibiting cellular repair or increasing the percentage of cells in mitotic phases of the growth cycle.

radiosensitizer
radiosensitizer (ra′de-o-sen-si-ti′zer)

A chemical substance that increases the radiosensitivity of tissues; restoring normal tissue oxygen tension to an anoxic region is also an effective r..

radiosodium
radiosodium (ra′de-o-so′de-um)

A radioactive isotope of sodium; e.g., ²⁴Na.

radiostereoscopy
radiostereoscopy (ra′de-o-ster-e-os′ko-pe)

Simultaneous viewing of two radiographs made in slightly different projections, usually with a device that reflects the image of one on each eye, allowing three-dimensional visualization of an object in relation to others. See stereoradiography, stereoscope. [radio- + G. stereos, solid, + skopeo, to view]

radiostrontium
radiostrontium (ra′de-o-stron′te-um)

A radioactive isotope of strontium; e.g., ⁹⁰Sr.

radiosulfur
radiosulfur (ra′de-o-sul′fur)

A radioactive isotope of sulfur; e.g., ³⁵S.

radiosurgery
radiosurgery (ra′de-o-sur-ge-re)

Radiotherapy with a sharply delimited field, optimistically considered to be equivalent to resecting the irradiated region.

radiotelemetry
radiotelemetry (ra′de-o-te-lem′e-tre)

See telemetry, biotelemetry.

radiotherapeutic
radiotherapeutic (ra′de-o-thar-a-pu′tik)

Relating to radiotherapy or to radiotherapeutics.

radiotherapeutics
radiotherapeutics (ra′de-o-thar-a-pu′tiks)

The study and use of radiotherapeutic agents.

radiotherapist
radiotherapist (ra′de-o-thar′a-pist)

One who practices radiotherapy or is versed in radiotherapeutics. SYN: radiation oncologist.

radiotherapy
radiotherapy (ra′de-o-thar′a-pe)

SYN: radiation oncology.
mantle r. r. with shielding of uninvolved radiosensitive structures or organs.

radiothermy
radiothermy (ra′de-o-ther′me)

Diathermy effected by heat from radiant sources. [radio- + G. therme, heat]

radiothyroidectomy
radiothyroidectomy (ra′de-o-thi′roy-dek′-to-me)

The destruction of thyroid tissue by administration of radioactive iodine.

radiothyroxin
radiothyroxin (ra′de-o-thi-rok′sin)

SYN: radioactive thyroxine.

radiotoxemia
radiotoxemia (ra′de-o-tok-se′me-a)

Radiation sickness caused by the products of disintegration produced by the action of x-rays or other forms of radioactivity and by the depletion of certain cells and enzyme systems from the organism. [radio- + G. toxikon, poison, + haima, blood]

radiotracer
radiotracer (ra′de-o-tra′ser)

A radionuclide or radiolabeled chemical; a radioactive tracer.

radiotransparent
radiotransparent (ra′de-o-trans-par′ent)

Allowing relatively free transmission of radiant energy. Cf.:radiolucent.

radiotropic
radiotropic (ra′de-o-trop′ik)

Affected by radiation. [radio- + G. trope, a turning]

radioulnar
radioulnar (ra′de-o-ul′nar)

Relating to both radius and ulna.

radisectomy
radisectomy (ra-de-sek′to-me)

SYN: root amputation. [L. radix, root, + G. ektome, excision]

radium
radium (Ra) (ra′de-um)

A metallic element, atomic no. 88, extracted in very minute quantities from pitchblende; ²²⁶Ra, its longest-lived isotope, is produced as an intermediate in the uranium series by the emission of an α particle from thorium-230 (ionium); ²²⁶Ra emits α particles and gamma rays with a half-life of 1,599 years breaking down to ²²²Rn; chemically, it is an alkaline earth metal with properties similar to those of barium. Its therapeutic action is similar to that of x-rays, since the α emission is filtered out. [L. radius, ray]

radius
radius, gen. and pl. radii (ra′de-us, ra′de-i) [TA]

1. [NA] The lateral and shorter of the two bones of the forearm. 2. A straight line passing from the center to the periphery of a circle. SYN: radio- (3) . [L. spoke of a wheel, rod, ray]
r. fixus a line passing from the hormion to the inion.
radii of lens [TA] 9–12 faint lines on the anterior and posterior surfaces of the lens that radiate from the poles toward the equator; they mark the lines along which the ends of lens fibers abut. SYN: radii lentis [TA] , lens stars (1) , lens sutures.
radii lentis [TA] SYN: radii of lens.

radix
radix, gen. radicis, pl .radices (ra′diks, ra-di′sis, ra′di-sez or ra-di′sez) [TA]

1. SYN: root (1) . 2. SYN: root of tooth. 3. The hypothetical size of the birth cohort in a life table, commonly 1,000 or 100,000. [L.]
r. accessoria [TA] SYN: accessory root of tooth.
r. anterior nervi spinalis [TA] SYN: anterior root of spinal nerve.
r. arcus vertebrae SYN: pedicle of arch of vertebra.
r. brevis ganglii ciliaris SYN: parasympathetic root of ciliary ganglion.
r. buccalis [TA] SYN: buccal root of tooth.
r. clinica dentis [TA] SYN: clinical root of tooth.
r. cranialis nervi accessorii [TA] SYN: cranial root of accessory nerve.
r. dentis [TA] SYN: root of tooth.
r. dorsalis nervi spinalis SYN: posterior root of spinal nerve.
r. facialis SYN: nerve of pterygoid canal.
r. inferior ansae cervicalis [TA] SYN: inferior root of ansa cervicalis.
r. inferior nervi vestibulocochlearis SYN: cochlear root of VIII nerve.
r. lateralis nervi mediani [TA] SYN: lateral root of median nerve.
r. lateralis tractus optici [TA] SYN: lateral root of optic tract.
r. linguae [TA] SYN: root of tongue.
r. longa ganglii ciliaris SYN: sensory root of ciliary ganglion.
r. medialis nervi mediani [TA] SYN: medial root of median nerve.
r. medialis tractus optici [TA] SYN: medial root of optic tract.
r. mesenterii [TA] SYN: root of mesentery.
r. motoria nervi spinalis anterior root of spinal nerve.
r. motoria nervi trigemini [TA] SYN: motor root of trigeminal nerve.
r. nasi [TA] SYN: root of nose.
r. nasociliaris ganglii ciliaris sensory root of ciliary ganglion.
r. nervi facialis SYN: root of facial nerve.
r. nervi oculomotorii ad ganglion ciliare parasympathetic root of ciliary ganglion.
radices nervi trigemini SYN: roots of trigeminal nerve, under root.
r. oculomotoria ganglii ciliaris parasympathetic root of ciliary ganglion.
r. parasympathica ganglii submandibularis SYN: chorda tympani.
radices parasympathicae gangliorum pelvicorum pelvic splanchnic nerves, under nerve.
r. parasympathica ganglii ciliaris [TA] SYN: parasympathetic root of ciliary ganglion.
r. parasympathica ganglii otici lesser petrosal nerve.
r. penis [TA] SYN: root of penis.
r. pili SYN: hair root.
r. posterior nervi spinalis [TA] SYN: posterior root of spinal nerve.
r. pulmonis [TA] SYN: root of lung.
r. sensoria ganglii ciliaris [TA] SYN: sensory root of ciliary ganglion.
r. sensoria ganglii pterygopalatini [TA] SYN: sensory root of pterygopalatine ganglion.
r. sensoria ganglii sublingualis [TA] SYN: sensory root of sublingual ganglion.
r. sensoria ganglii submandibularis [TA] SYN: sensory root of submandibular ganglion.
r. sensoria nervi spinalis posterior root of spinal nerve.
r. sensoria nervi trigemini [TA] SYN: sensory root of trigeminal nerve.
r. spinalis nervi accessorii [TA] SYN: spinal root of accessory nerve.
r. superior ansae cervicalis [TA] SYN: superior root of ansa cervicalis.
r. superior nervi vestibulocochlearis SYN: vestibular root.
r. sympathica ganglii ciliaris [TA] SYN: sympathetic root of ciliary ganglion.
r. sympathica ganglii otici [TA] SYN: sympathetic root of otic ganglion.
r. sympathica ganglii pterygopalatini deep petrosal nerve.
r. sympathica ganglii sublingualis [TA] SYN: sympathetic root of sublingual ganglion.
r. sympathica ganglii submandibularis [TA] SYN: sympathetic root of submandibular ganglion.
r. unguis SYN: root of nail.
r. ventralis nervi spinalis SYN: anterior root of spinal nerve.
r. vestibularis SYN: vestibular root.

radon
radon (Rn) (ra′don)

A gaseous radioactive element, atomic no. 86, resulting from the breakdown of radium; of the isotopes with mass numbers between 198 and 228, only ²²²Rn is medically significant as an alpha-emitter, with a half-life of 3.8235 days; it is used in the treatment of certain malignancies. Poorly ventilated homes in some parts of the country accumulate a dangerous amount of naturally occurring r. gas. [from radium]

Raeder
Raeder

Georg Johann, Norwegian ophthalmologist, 1889–1956. See R. paratrigeminal syndrome.

raffinose
raffinose (raf′i-nos)

A dextrorotatory trisaccharide, occurring in cotton seed and in the molasses of beet root, composed of d-galactose, d-glucose, and d-fructose and formed by transfer of d-galactose from UDP-d-galactose to sucrose; many seeds are rich in r.. SYN: gossypose, melitose, melitriose.

rage
rage (raj)

Violent anger; a total discharge of the sympathetic portion of the autonomic nervous system. [Fr., fr. L. rabies, violent anger, fr. rabo, to rave]
sham r. a quasiemotional state, characterized by manifestations of fear and anger upon trifling provocation; produced in animals by the removal of the cerebral cortex (decortication).

Rahe
Rahe

Richard H., U.S. psychiatrist, *1936. See Holmes-R. questionnaire.

Rahn
Rahn

Hermann, U.S. respiratory physiologist, 1912–1990. See R.-Otis sample.

Raillietina
Raillietina (ri-li-e-te′na)

A genus of tapeworms (family Davaineidae, order Cyclophyllidea), three species of which, R. madagascariensis or R. demerariensis, R. asiatica, and R. formsana, have been found in humans. However, the identification of many of these worms found in humans has been questioned.

raillietiniasis
raillietiniasis (ri′li-e-ti-ni′a-sis)

Infection of rodents and monkeys, and occasionally humans, with tapeworms of the genus Raillietina.

Rainey
Rainey

George, English anatomist, 1801–1884. See R. corpuscles, under corpuscle.

rale
rale (rahl)

Ambiguous term for an added sound heard on auscultation of breath sounds; used by some to denote rhonchus and by others for crepitation. SYN: crackle. [Fr. rattle]
amphoric r. sound heard through the stethoscope associated with the movement of fluid in a lung cavity communicating with a bronchus.
atelectatic r. transitory light crackling sound that disappears after deep breathing or coughing.
bubbling r. moist sound heard through the stethoscope as a result of air entering portions of lung tissue containing exudate and thus creating bubbles; sometimes associated with resolving pneumonia or small lung cavities.
cavernous r. a resonating, bubbling sound caused by air entering a cavity partly filled with fluid. SYN: cavernous rhonchus.
clicking r. short, sticking sound usually associated with opening of small bronchi on deep breathing, sometimes heard in early pulmonary tuberculosis.
consonating r. a resonant r. produced in a bronchial tube and heard through consolidated lung tissue.
crackling r. (krak′ling) very fine sounds produced by fluid in very small airways in pneumonia or congestive heart failure.
crepitant r. a fine bubbling or crackling sound produced by air mixing with very thin secretions in the smaller bronchial tubes. SYN: vesicular r..
dry r. a harsh or musical breath sound produced by a constriction in a bronchial tube or the presence of a viscid secretion narrowing the lumen.
gurgling r. coarse sound heard over large cavities or over trachea nearly filled with secretions.
guttural r. sound heard over the lung but resulting from upper airway obstruction.
metallic r. a r. of metallic quality caused by resonance in a large cavity.
moist r. a bubbling r. caused by air mixing with a fluid exudate in the bronchial tubes or a cavity.
mucous r. a bubbling r. heard on auscultation over bronchial tubes containing mucus.
palpable r. a vibration that can be felt accompanying a low-pitched, hard, musical, or sonorous r..
pleural r. SYN: pleural rub.
sibilant r. a whistling sound caused by air moving through a viscid secretion narrowing the lumen of a bronchus. SYN: whistling r..
Skoda r. a r. in a bronchus heard through an area of consolidated tissue in pneumonia.
sonorous r. a cooing or snoring sound often produced by the vibration of a projecting mass of viscid secretion in a large bronchus.
subcrepitant r. a very fine crepitant r..
vesicular r. SYN: crepitant r..
whistling r. SYN: sibilant r..

raloxifene raloxifene (ral-ox′i-fen)

A selective estrogen receptor modulator (SERM) that has estrogen-agonistic effects on bone and lipid metabolism but estrogen-antagonistic effects on breast and uterus; used in the prophylaxis of osteoporosis after menopause.R. is a benzothiophene derivative that binds to estrogen receptor sites. Besides conferring protection against osteoporosis after menopause, it has been shown to improve bone mineral density and reduce the risk of fractures in established osteoporosis. The reduction in fracture risk is greater than would be expected from the increase in bone density. Unlike tamoxifen, which also reduces osteoporosis risk, r. does not heighten the risk of endometrial cancer. Although r. increases bone mineral density to a lesser degree than estrogen, it reduces the risk of breast cancer rather than increasing it as estrogen may perhaps do. Hence it may be preferred for women who fear breast cancer or are at high risk for it. Like hormone replacement therapy with estrogen-progestogen, r. decreases LDL cholesterol, fibrinogen, and lipoprotein(a), increasing HDL cholesterol without raising triglycerides. It does not relieve hot flashes; in fact, it causes them in 25% of patients. Like estrogen replacement therapy, it is contraindicated in pregnancy and in women with a history of thromboembolism. Whether it protects against cardiovascular disease and Alzheimer dementia as estrogen does has not yet been determined.

ramal
ramal (ra′mal)

Relating to a ramus.

Raman
Raman

Sir Chandrasekhara V., Indian physicist and Nobel laureate, 1888–1970. See R. effect, R. spectrum.

Rambourg stains
Rambourg stains

See Rambourg chromic acid-phosphotungstic acid stain, Rambourg periodic acid-chromic methenamine-silver stain.

rami
rami (ra′mi)

Plural of ramus. [L.]

ramicotomy
ramicotomy (ram-i-kot′o-me)

SYN: ramisection. [L. ramus, branch, + G. tome, incision]

ramification
ramification (ram′i-fi-ka′shun)

The process of dividing into a branchlike pattern.

ramify
ramify (ram′i-fi)

To split into a branchlike pattern. [L. ramus, branch, + facio, to make]

ramisection
ramisection (ram-i-sek′shun)

Section of the rami communicantes of the sympathetic nervous system. SYN: ramicotomy. [L. ramus, branch, + L. sectio, section]

ramitis
ramitis (ram-i′tis)

Inflammation of a ramus. [L. ramus, branch, + G. -itis, inflammation]

Ramón y Cajal
Ramón y Cajal

See Cajal.

ramose
ramose, ramous (ra′mos, ra′mus)

SYN: branching. [L. ramosus, fr. ramus, a branch]

ramp
ramp

In electrical recording, a uniformly rising voltage or current. If reset to zero at regular intervals, it forms a sawtooth pattern used to provide the time sweep of a cathode ray oscilloscope beam; if reset to zero by a periodic event ( e.g., heart beats), the recorded height of the ramps represents time between events.

Ramsay Hunt Ramsay Hunt

See Hunt.

Ramsden
Ramsden

Jesse, English optician, 1735–1800. See R. ocular.

Ramstedt
Ramstedt

Conrad, German surgeon, 1867–1962. See R. operation, Fredet-R. operation.

ramulus
ramulus, pl .ramuli (ram′u-lus, -li)

A small branch or twig; one of the terminal divisions of a ramus. [L. dim. of ramus, a branch]

ramus
ramus, pl .rami (ra′mus, ra′mi) [TA]

1. SYN: branch. 2. One of the primary divisions of a nerve or blood vessel. Arterial and nerve branches are also given under the major nerve or artery. See artery, nerve. 3. A part of an irregularly shaped bone (less slender than a “process”) that forms an angle with the main body ( e.g., r. of mandible). 4. One of the primary divisions of a cerebral sulcus. [L.]
r. accessorius arteriae meningeae mediae [TA] SYN: accessory branch of middle meningeal artery.
r. acetabularis [TA] SYN: acetabular branch.
r. acromialis arteriae suprascapularis [TA] SYN: acromial branch of suprascapular artery.
r. acromialis arteriae thoracoacromialis [TA] SYN: acromial branch of thoracoacromial artery.
rami ad pontem SYN: pontine arteries, under artery.
rami alveolares superiores anteriores nervi infraorbitalis SYN: anterior superior alveolar nerves, under nerve.
rami alveolares superiores posteriores nervi maxillaris [TA] SYN: posterior superior alveolar branches of maxillary nerve, under branch.
r. alveolaris superior medius nervi infraorbitalis [TA] SYN: middle superior alveolar branch of infraorbital nerve.
r. anastomoticus [TA] SYN: anastomotic branch. SEE ALSO: communicating branch.
r. anastomoticus arteriae meningeae mediae cum arteriae lacrimali [TA] SYN: anastomotic branch of middle meningeal artery with lacrimal artery.
r. anterior [TA] SYN: anterior branch.
r. anterior arteriae renalis [TA] See segmental arteries of kidney, under artery.
anterior rami of cervical nerves [TA] See anterior r. of spinal nerve. SYN: rami anteriores nervorum cervicalium [TA] , ventral rami of cervical nerves&star, rami ventrales nervorum cervicalium, ventral primary rami of cervical spinal nerves.
r. anterior descendens SYN: descending branch of anterior segmental artery of left and right lungs.
rami anteriores nervorum cervicalium [TA] SYN: anterior rami of cervical nerves.
rami anteriores nervorum lumbalium [TA] SYN: anterior rami of lumbar nerves.
rami anteriores nervorum sacralium [TA] SYN: anterior rami of sacral nerves.
rami anteriores nervorum thoracis [TA] SYN: anterior rami of thoracic nerves.
r. anterior lateralis the lateral anterior branch, the former name for the ascending anterior branch of the left pulmonary artery.
anterior r. of lateral sulcus of cerebrum [TA] SYN: r. anterior sulci lateralis cerebri [TA] .
anterior rami of lumbar nerves [TA] See anterior r. of spinal nerve. SYN: rami anteriores nervorum lumbalium [TA] , ventral rami of lumbar nerves&star, rami ventrales nervorum lumbalium, ventral primary rami of lumbar spinal nerves.
r. anterior nervi spinalis [TA] SYN: anterior r. of spinal nerve.
anterior rami of sacral nerves [TA] See anterior r. of spinal nerve. SYN: rami anteriores nervorum sacralium [TA] , ventral rami of sacral nerves&star, rami ventrales nervorum sacralium, ventral primary rami of sacral spinal nerves.
anterior r. of spinal nerve [TA] the larger, anterolaterally directed major terminal branch (with the posterior r.) of all 31 pairs of mixed spinal nerves, formed at the intervertebral foramen. Most anterior rami, especially those involved in the innervation of the limbs, participate in the formation of the major nerve plexuses (cervical, brachial, and lumbosacral) and lose their identities. Most in the thoracic region, however, remain separate from adjacent rami to become the intercostal and subcostal nerves. Anterior rami provide innervation to the anterolateral body wall and trunk. Terminologia Anatomica lists anterior rami for each group of spinal nerves: 1) cervical (nervorum cervicalium [TA]), 2) thoracic (nervorum thoracicorum [TA]), 3) lumbar (nervorum lumbalium [TA]), 4) sacral (nervorum sacralium [TA]), and 5) coccygeal (nervi coccygei [TA]). SYN: r. anterior nervi spinalis [TA] , r. ventralis nervi spinalis&star, ventral r. of spinal nerve&star, anterior primary division, ventral primary r. of spinal nerve.
r. anterior sulci lateralis cerebri [TA] SYN: anterior r. of lateral sulcus of cerebrum.
anterior rami of thoracic nerves [TA] See anterior r. of spinal nerve. SYN: rami anteriores nervorum thoracis [TA] , rami ventrales nervorum thoracis&star, ventral rami of thoracic nerves&star, ventral primary rami of thoracic spinal nerves.
r. apicalis lobi inferioris arteriae pulmonalis dextrae apical segmental artery of superior lobar artery of right lung.
r. apicalis venae pulmonalis dextrae superioris apical vein.
r. apicoposterior venae pulmonalis sinistrae superioris apicoposterior vein.
rami articulares [TA] SYN: articular branches, under branch.
rami articulares arteriae descendentis genicularis articular branches, under branch.
r. ascendens [TA] SYN: ascending branch.
r. ascendens arteriae superficialis cervicalis [TA] SYN: ascending branch of superficial cervical artery.
r. ascendens sulci lateralis cerebri [TA] SYN: ascending r. of lateral sulcus of cerebrum.
ascending r. of lateral sulcus of cerebrum [TA] SYN: r. ascendens sulci lateralis cerebri [TA] .
rami atriales [TA] SYN: atrial branches, under branch.
r. atrialis anastomoticus r. circumflexus arteriae coronariae sinistrae [TA] SYN: atrial anastomotic branch of circumflex branch of left coronary artery.
r. atrialis intermedius arteriae coronariae dextrae [TA] SYN: intermediate atrial branch of right coronary artery.
rami auriculares anteriores arteriae temporalis superficialis [TA] SYN: anterior auricular branches of superficial temporal artery, under branch.
r. auricularis arteriae auricularis posterioris [TA] SYN: auricular branch of posterior auricular artery.
r. auricularis arteriae occipitalis [TA] SYN: auricular branch of occipital artery.
r. auricularis nervi vagi SYN: auricular branch of vagus nerve.
r. basalis anterior SYN: anterior basal segmental artery.
r. basalis anterior venae basalis superioris anterior basal vein.
r. basalis lateralis SYN: lateral basal segmental artery.
r. basalis medialis SYN: medial basal segmental artery.
r. basalis posterior SYN: posterior basal segmental artery of left / right lung.
r. basalis tentorii arteriae carotidis internae [TA] SYN: tentorial basal branch of internal carotid artery.
rami bronchiales SYN: bronchial branches of thoracic aorta, under branch.
rami bronchiales segmentorum SYN: intrasegmental bronchi, under bronchus.
rami buccales nervi facialis [TA] SYN: buccal branches of facial nerve, under branch.
rami calcanei [TA] SYN: calcaneal branches, under branch.
rami calcanei laterales nervi suralis [TA] SYN: lateral calcaneal branches of sural nerve, under branch.
rami calcanei mediales nervi tibialis [TA] SYN: medial calcaneal branches of tibial nerve, under branch.
r. calcarinus arteriae occipitalis medialis [TA] SYN: calcarine branch of medial occipital artery.
rami capsulae internae the internal capsular branches, the branches of the anterior choroid artery to the internal capsule. SYN: branches to internal capsule, genu [TA] , branches to internal capsule, posterior limb [TA] , rami cruris posterioris capsulae internae [TA] , rami genus capsulae internae [TA] , rami partis retrolentiformis capsulae internae [TA] , branches to internal capsule, retrolentiform limb.
rami capsulares arteriorum intrarenalium [TA] SYN: capsular branches of intrarenal arteries, under branch.
rami capsulares arteriae renalis [TA] SYN: capsular branches of renal artery, under branch.
rami cardiaci cervicales inferiores nervi vagi [TA] SYN: inferior cervical cardiac branches of vagus nerve, under branch.
rami cardiaci cervicales superiores nervi vagi [TA] SYN: superior cervical cardiac branches of vagus nerve, under branch.
rami cardiaci thoracici gangliorum thoracicorum [TA] SYN: thoracic cardiac branches of thoracic ganglia, under branch.
rami cardiaci thoracici nervi vagi [TA] SYN: thoracic cardiac branches of vagus nerve, under branch.
r. cardiacus obsolete term for medial basal branch of pulmonary artery.
rami caroticotympanici SYN: caroticotympanic arteries (of internal carotid artery), under artery.
r. carpalis dorsalis arteriae radialis [TA] SYN: dorsal carpal branch of radial artery.
r. carpalis dorsalis arteriae ulnaris [TA] SYN: dorsal carpal branch of ulnar artery.
r. carpalis palmaris arteriae radialis [TA] SYN: palmar carpal branch of radial artery.
r. carpalis palmaris arteriae ulnaris [TA] SYN: palmar carpal branch of ulnar artery.
r. carpeus dorsalis arteriae radialis SYN: dorsal carpal branch of radial artery.
r. carpeus dorsalis arteriae ulnaris SYN: dorsal carpal branch of ulnar artery.
r. carpeus palmaris arteriae radialis SYN: palmar carpal branch of radial artery.
r. carpeus palmaris arteriae ulnaris SYN: palmar carpal branch of ulnar artery.
rami caudae nuclei caudati [TA] branches to the tail of the caudate nucleus. 1. branches from either the anterior choroid or the posterior communicating artery, or both, to supply the tail of the caudate nucleus; 2. a branch from the middle cerebral artery to the tail of the caudate nucleus.
rami celiaci nervi vagi SYN: celiac branches of posterior vagal trunk, under branch.
rami celiaci trunci vagi posterioris [TA] SYN: celiac branches of posterior vagal trunk, under branch.
rami centrales anteromediales [TA] SYN: anteromedial central branches, under branch.
cephalic arterial rami parietal branches of the sympathetic trunks conveying postsynaptic sympathetic fibers from the superior cervical ganglion to the carotid arteries for distribution within the head.
r. cervicalis nervi facialis cervical branch of facial nerve.
r. chiasmaticus [TA] the chiasmatic branch, a branch of the anterior cerebral artery to the optic chiasm.
rami choroidei SYN: choroid branches, under branch.
rami choroidei posteriores arteriae cerebri posteriores laterales et mediales [TA] SYN: lateral and medial posterior choroidal branches of posterior cerebral artery, under branch.
r. choroidei posteriores laterales [TA] posterior lateral choroid branches [TA] of posterior cerebral artery. See choroid branches, under branch.
r. choroidei posteriores mediales [TA] posterior medial choroid branches [TA] of posterior cerebral artery. See choroid branches, under branch.
r. choroidei ventriculi lateralis [TA] choroidal branches to lateral ventricle [TA] of anterior choroid artery. See choroid branches, under branch.
r. choroidei ventriculi tertii third ventricle choroid branch of anterior artery. See choroid branches, under branch.
r. choroideus ventriculi quarti [TA] choroidal branch to fourth ventricle [TA] of posterior inferior cerebellar artery. See choroid branches, under branch.
r. cingularis [TA] cingular branch [TA], a branch of the callosomarginal artery supplying the gyrus cinguli.
r. cingularis arteriae callosomarginalis [TA] SYN: cingular branch of callosomarginal artery.
r. circumflexus arteriae coronariae sinistrae [TA] SYN: circumflex branch of left coronary artery.
r. circumflexus fibularis arteriae tibialis posterioris [TA] SYN: circumflex fibular branch (of posterior tibial artery).
r. circumflexus peronealis arteriae tibialis posterioris circumflex fibular branch (of posterior tibial artery).
r. clavicularis arteriae thoracoacromialis [TA] SYN: clavicular branch of thoracoacromial artery.
rami clivales [TA] clivus branches [TA], the branch to the clivus, a branch of the cerebral part of the internal carotid artery supplying the clivus.
rami clivales partis cerebralis arteriae carotidis internae [TA] SYN: clivus branches of cerebral part of internal carotid artery, under branch.
r. cochlearis arteriae labyrinthi SYN: cochlear branch of vestibulocochlear artery.
r. cochlearis arteriae vestibulocochlearis [TA] SYN: cochlear branch of vestibulocochlear artery.
r. colicus arteriae ileocolicae [TA] SYN: colic branch of ileocolic artery.
r. collateralis arteriarum intercostalium posteriorum III–XI [TA] SYN: collateral branches of posterior intercostal arteries 3–11, under branch.
r. collateralis nervorum intercostalium [TA] SYN: collateral branch of intercostal nerves.
r. colli nervi facialis [TA] SYN: cervical branch of facial nerve.
r. communicans, pl .rami communicantes [TA] SYN: communicating branch.
r. communicans arteriae fibularis [TA] SYN: communicating branch of fibular artery.
r. communicans arteriae peroneae communicating branch of fibular artery.
r. communicans cum chorda tympani [TA] 1. SYN: communicating branch of chorda tympani with lingual nerve. 2. SYN: communicating branch of otic ganglion with chorda tympani.
r. communicans cum nervo glossopharyngeo 1. SYN: communicating branch of facial nerve with glossopharyngeal nerve. 2. SYN: communicating branch of tympanic plexus with auricular branch of vagus nerve.
r. communicans fibularis nervi fibularis communis [TA] SYN: sural communicating branch of common fibular nerve.
r. communicans ganglii otici cum chorda tympani SYN: communicating branch of otic ganglion with chorda tympani.
r. communicans ganglii otici cum nervo auriculotemporali SYN: communicating branch of otic ganglion to auriculotemporal nerve.
r. communicans ganglii otici cum nervo pterygoideo mediali SYN: communicating branch of otic ganglion with medial pterygoid nerve.
r. communicans ganglii otici cum ramo meningeo nervi mandibularis SYN: communicating branch of otic ganglion with meningeal branch of mandibular nerve.
rami communicantes nervi auriculotemporalis cum nervo faciali [TA] SYN: communicating branches of auriculotemporal nerve with facial nerve, under branch.
r. communicans nervi facialis cum nervo glossopharyngeo [TA] SYN: communicating branch of facial nerve with glossopharyngeal nerve.
r. communicans nervi facialis cum plexu tympanico SYN: communicating branch of intermediate nerve with tympanic plexus.
r. communicans nervi fibularis communis cum nervo cutaneo surae mediali sural communicating branch of common fibular nerve.
r. communicans nervi glossopharyngei cum ramo auriculari nervi vagi SYN: communicating branch of tympanic plexus with auricular branch of vagus nerve.
r. communicans nervi intermedii cum plexu tympanico [TA] SYN: communicating branch of intermediate nerve with tympanic plexus.
r. communicans nervi interossei antebrachii anterioris cum nervi ulnari [TA] SYN: communicating branch of anterior interosseous nerve with ulnar nerve.
r. communicans nervi lacrimalis cum nervo zygomatico [TA] SYN: communicating branch of lacrimal nerve with zygomatic nerve.
r. communicans nervi laryngei interni cum nervo laryngeo recurrente [TA] SYN: communicating branch of internal laryngeal nerve with recurrent laryngeal nerve.
r. communicans nervi laryngei recurrentis cum ramo laryngeo interno SYN: communicating branch of internal laryngeal nerve with recurrent laryngeal nerve.
r. communicans nervi laryngei superioris cum nervo laryngeo recurrenti SYN: communicating branch of internal laryngeal nerve with recurrent laryngeal nerve.
r. communicans nervi lingualis cum chorda tympani SYN: communicating branch of chorda tympani with lingual nerve.
rami communicantes nervi lingualis cum nervo hypoglosso [TA] SYN: communicating branches of lingual nerve with hypoglossal nerve, under branch.
r. communicans nervi mediani cum nervo ulnari SYN: communicating branch of median nerve with ulnar nerve.
r. communicans nervi nasociliaris cum ganglio ciliari sensory root of ciliary ganglion.
r. communicans nervi peronei communis cum nervo cutaneo surae mediali sural communicating branch of common fibular nerve.
r. communicans nervi radialis cum nervi ulnari [TA] SYN: communicating branch of radial nerve with ulnar nerve.
rami communicantes nervorum spinalium SYN: white rami communicantes.
r. communicans peroneus nervi peronei communis sural communicating branch of common fibular nerve.
r. communicans plexus tympanici cum ramo auriculari nervi vagi [TA] SYN: communicating branch of tympanic plexus with auricular branch of vagus nerve.
r. communicans ulnaris nervi radialis SYN: communicating branch of superficial radial nerve with ulnar nerve.
rami communicantes albi [TA] SYN: white rami communicantes.
rami communicantes ganglii sublingualis cum nervo linguali sensory root of sublingual ganglion.
rami communicantes grisei [TA] SYN: gray rami communicantes.
rami communicantes of sympathetic part of autonomic division of nervous system the communicating branches of the spinal nerves and sympathetic trunk, small bundles of nerve fibers connecting spinal nerves with sympathetic ganglia; the fibers passing from the ganglion to the spinal nerve are nonmyelinated and are called gray rami communicantes, those passing in the reverse direction are myelinated and are called white rami communicantes.
communicating rami of sympathetic trunk SYN: gray rami communicantes.
rami corporis amygdaloidei [TA] branches to amygdaloid body [TA], branches of the anterior choroid artery to the amygdaloid body.
r. corporis callosi dorsalis [TA] dorsal branch to corpus callosum [TA], branches of the medial occipital artery to the dorsum of the corpus callosum.
rami corporis geniculati lateralis [TA] branches to lateral geniculate body [TA] branches, branches of the anterior choroid artery to the lateral geniculate body.
r. costalis lateralis arteriae thoracicae internae [TA] SYN: lateral costal branch of internal thoracic artery.
r. cricothyroideus (arteriae thyroideae superioris) SYN: cricothyroid branch of superior thyroid artery.
rami cruris posterioris capsulae internae [TA] SYN: rami capsulae internae.
rami cutanei anteriores nervi femoralis [TA] SYN: anterior cutaneous branches of femoral nerve, under branch.
rami cutanei anteriores pectoralis et abdominalis nervorum intercostalium SYN: thoracoabdominal nerves, under nerve.
rami cutanei cruris mediales nervi sapheni [TA] SYN: medial cutaneous nerve of leg.
r. cutaneus anterior abdominalis nervi intercostalis [TA] SYN: anterior abdominal cutaneous branch of intercostal nerve.
r. cutaneus anterior pectoralis nervi intercostalis [TA] SYN: anterior pectoral cutaneous branch of intercostal nerves.
r. cutaneus anterior nervi iliohypogastrici [TA] SYN: anterior cutaneous branch of iliohypogastric nerve.
r. cutaneus anterior (pectoralis et abdominalis) nervorum thoracicorum SYN: thoracoabdominal nerves, under nerve.
r. cutaneus lateralis [TA] SYN: lateral cutaneous branch.
r. cutaneus lateralis abdominalis/pectoralis nervorum intercostalium SYN: lateral abdominal/pectoral cutaneous branches of intercostal nerves, under branch.
r. cutaneus lateralis nervi iliohypogastrici lateral cutaneous branch of iliohypogastric nerve. See lateral cutaneous branch.
r. cutaneus lateralis ramorum posteriorum arteriae intercostalium lateral cutaneous branch of dorsal branch of posterior intercostal arteries. See lateral cutaneous branch.
r. cutaneus medialis rami dorsalis arteriarum intercostalium posteriorum III–XI SYN: medial cutaneous branch of dorsal branch of posterior intercostal arteries. See medial cutaneous branch of dorsal branch of posterior intercostal arteries.
r. cutaneus medialis ramorum dorsalium nervorum thoracicorum medial cutaneous branch of dorsal branch of thoracic nerves. See medial cutaneous branch of dorsal branch of posterior intercostal arteries.
r. cutaneus nervi mixti [TA] SYN: cutaneous branch of mixed nerve.
r. cutaneus rami anterioris nervi obturatorii [TA] SYN: cutaneous branch of anterior branch of obturator nerve.
r. deltoideus [TA] SYN: deltoid branch.
r. deltoideus arteriae profundae brachii [TA] SYN: profunda brachii artery.
r. deltoideus arteriae thoracoacromialis [TA] SYN: thoracoacromial artery.
dental rami SYN: dental branches, under branch.
rami dentales [TA] SYN: dental branches, under branch.
rami dentales arteriae alveolaris inferioris dental branches of inferior alveolar artery. See dental branches, under branch.
rami dentales arteriae alveolaris superioris posterioris dental branch of the posterior superior alveolar artery. See dental branches, under branch.
rami dentales inferiores [TA] SYN: inferior dental branches of inferior dental plexus, under branch. See dental branches, under branch.
rami dentales inferiores plexus dentalis inferioris [TA] SYN: inferior dental branches of inferior dental plexus, under branch.
rami dentales superiores [TA] SYN: superior dental branches of superior dental plexus, under branch.
rami dentales superiores plexus dentalis superioris [TA] SYN: superior dental branches of superior dental plexus, under branch.
r. descendens [TA] SYN: descending branch.
r. descendens arteriae circumflexae femoris lateralis [TA] SYN: descending branch of lateral circumflex femoral artery.
r. descendens arteriae circumflexae femoris medialis [TA] SYN: descending branch of medial circumflex femoral artery.
r. descendens arteriae occipitalis [TA] SYN: descending branch of occipital artery.
r. descendens arteriae segmentalis anterioris pulmonis dextri et sinistri [TA] SYN: descending branch of anterior segmental artery of left and right lungs.
r. descendens arteriae segmentalis posterioris pulmonis dextri et sinistri [TA] SYN: descending branch of posterior segmental artery of left and right lungs.
r. descendens rami superficialis arteriae transversae cervicis [TA] SYN: descending branch of superficial cervical artery.
r. dexter [TA] SYN: right branch.
r. dexter arteriae hepaticae propriae [TA] SYN: right branch of hepatic artery proper.
r. dexter venae portae hepatis [TA] SYN: right branch of portal vein.
r. digastricus nervi facialis [TA] SYN: digastric branch of facial nerve.
rami dorsales arteriarum intercostalium posteriorum primae et secundae [TA] SYN: dorsal branches of first and second posterior intercostal artery, under branch.
rami dorsales arteriae intercostalis supremae SYN: dorsal branches of first and second posterior intercostal artery, under branch.
rami dorsales arteriae subcostalis SYN: dorsal branch of the subcostal artery.
r. dorsales arteriae subcostalis [TA] SYN: dorsal branch of the subcostal artery.
rami dorsales linguae arteriae lingualis [TA] SYN: dorsal lingual branches of lingual artery, under branch.
rami dorsales nervi ulnaris [TA] SYN: dorsal branch of the ulnar nerve.
r. dorsalis SYN: posterior r. of spinal nerve.
r. dorsalis arteriae lumbalis [TA] SYN: dorsal branch of the lumbar artery.
r. dorsalis arteriarum intercostalium posteriorum III–XI [TA] SYN: dorsal branch of the posterior intercostal arteries 3–11.
r. dorsalis nervi spinalis posterior r. of spinal nerve.
r. dorsalis venarum intercostalium posteriorum IV–XI [TA] SYN: dorsal branch of the posterior intercostal veins 4–11.
dorsal primary r. of spinal nerve posterior r. of spinal nerve.
rami duodenales arteriae pancreaticoduodenalis superioris anterioris [TA] SYN: duodenal branches of anterior superior pancreaticoduodenal artery, under branch.
rami epiploicae SYN: omental branches, under branch.
rami esophageales esophageal branches, under branch.
rami esophageales aortae thoracicae esophageal branches of the thoracic aorta, under branch.
rami esophageales arteriae gastricae sinistrae [TA] SYN: esophageal branches of the left gastric artery, under branch.
rami esophageales arteriae thyroideae inferioris [TA] SYN: esophageal branches of the inferior thyroid artery, under branch.
rami esophageales gangliorum thoracicorum [TA] SYN: esophageal branches of thoracic ganglia, under branch.
rami esophageales partis thoracicae aortae [TA] SYN: esophageal branches of the thoracic aorta, under branch.
rami esophagei [TA] SYN: esophageal branches, under branch.
rami esophagei nervi laryngei recurrentis [TA] SYN: esophageal branches of the recurrent laryngeal nerve, under branch.
rami esophagei nervi vagi SYN: esophageal branches of the vagus nerve, under branch.
r. externus nervi laryngei superioris [TA] SYN: external branch of superior laryngeal nerve.
r. externus trunci nervi accessorii [TA] SYN: external branch of trunk of accessory nerve.
rami fauciales nervi lingualis SYN: branches of lingual nerve to isthmus of fauces, under branch.
r. femoralis nervi genitofemoralis [TA] SYN: femoral branch of genitofemoral nerve.
r. frontalis anteromedialis [TA] anteromedial frontal branch [TA] of the callosomarginal artery.
r. frontalis anteromedialis arteriae callosomarginalis [TA] SYN: anteromedial frontal branch of callosomarginal artery.
r. frontalis arteriae meningeae mediae [TA] SYN: frontal branch of middle meningeal artery.
r. frontalis arteriae temporalis superficialis [TA] SYN: frontal branch of superficial temporal artery.
r. frontalis intermediomedialis [TA] intermediomedial frontal branch [TA] of the callosomarginal artery.
r. frontalis intermediomedialis arteriae callosomarginalis [TA] SYN: intermediomedial frontal branch of callosomarginal artery.
r. frontalis posteromedialis [TA] posteromedial frontal branch [TA] of the callosomarginal artery.
r. frontalis posteromedialis arteriae callosomarginalis [TA] SYN: posteromedial frontal branch of callosomarginal artery.
rami ganglii submandibularis SYN: glandular branches of submandibular ganglion, under branch.
rami communicantes ganglii submandibularis cum nervo linguali sensory root of submandibular ganglion.
r. ganglii trigeminalis SYN: branches of internal carotid artery to trigeminal ganglion, under branch.
rami ganglionares SYN: sensory root of pterygopalatine ganglion.
r. ganglionares trigeminales arteriae carotidis internae [TA] SYN: branches of internal carotid artery to trigeminal ganglion, under branch.
rami ganglionici nervi maxillaris sensory root of pterygopalatine ganglion.
rami gastrici anteriores nervi vagi SYN: anterior gastric branches of anterior vagal trunk, under branch.
rami gastrici anteriores trunci vagalis anterioris [TA] SYN: anterior gastric branches of anterior vagal trunk, under branch.
rami gastrici posteriores nervi vagi SYN: gastric branches of posterior vagal trunk, under branch.
rami gastrici posteriores trunci vagalis posterioris [TA] SYN: posterior gastric branches of posterior vagal trunk, under branch.
r. genitalis nervi genitofemoralis [TA] SYN: genital branch of genitofemoral nerve.
rami genus capsulae internae [TA] SYN: rami capsulae internae.
rami gingivales inferiores plexus dentalis inferioris [TA] SYN: inferior gingival branches of inferior dental plexus, under branch.
rami gingivales superiores plexus dentalis superioris [TA] SYN: superior gingival branches of superior dental plexus, under branch.
rami glandulares [TA] SYN: glandular branches, under branch.
r. glandulares anterior/lateralis/posterior arteriae thyroideae superioris SYN: anterior/lateral/posterior glandular branches of superior thyroid artery, under branch.
rami glandulares arteriae facialis [TA] SYN: glandular branches of facial artery, under branch.
rami glandulares arteriae thyroideae inferioris [TA] SYN: glandular branches of inferior thyroid artery, under branch.
rami glandulares ganglii submandibularis SYN: glandular branches of submandibular ganglion, under branch.
r. glandularis anterior arteriae thyroideae superioris [TA] SYN: anterior glandular branch of superior thyroid artery.
r. glandularis posterior arteriae thyroideae superioris [TA] SYN: posterior glandular branch of superior thyroid artery.
rami globi pallidi [TA] branches to globus pallidus [TA], branches of the anterior choroid artery to the globus pallidus.
gray rami communicantes [TA] short nerves arising from the lateral aspect of the sympathetic trunk conducting nonmyelinated postsynaptic sympathetic nerve fibers from the sympathetic trunk to the initial portions of all 31 pairs of ventral primary rami of spinal nerves for distribution by all parts (including the dorsal primary r.) of the spinal nerve. The gray rami are the parietal branches of the sympathetic trunks since all postsynaptic fibers to be distributed to the body wall (including limbs) must pass through them. SYN: rami communicantes grisei [TA] , communicating branches of sympathetic trunk, communicating rami of sympathetic trunk.
rami hepatici nervi vagi SYN: hepatic branches of anterior vagal trunk, under branch.
rami hepatici trunci vagi anterior [TA] SYN: hepatic branches of anterior vagal trunk, under branch.
r. hypothalamicus [TA] the hypothalamic branch, a branch of the anterior cerebral artery to the hypothalamus.
r. iliacus arteriae iliolumbalis [TA] SYN: iliacus branch of iliolumbar artery.
r. inferior [TA] SYN: inferior branch.
r. inferior arteriae gluteae superioris [TA] SYN: inferior branch of superior gluteal artery.
inferior dental rami SYN: inferior dental branches of inferior dental plexus, under branch.
rami inferiores nervi transversi cervicalis [colli] SYN: inferior branches of transverse cervical nerve, under branch.
rami inferiores nervi transversi colli inferior branches of transverse cervical nerve, under branch.
r. inferior nervi oculomotorii [TA] SYN: inferior branch of oculomotor nerve.
r. inferior ossis pubis [TA] SYN: inferior pubic r..
inferior pubic r. [TA] inferior extension from body of pubic bone that meets with the r. of the ischium to form the ischiopubic r.. SYN: r. inferior ossis pubis [TA] .
r. infrahyoideus arteriae thyroideae superioris [TA] SYN: infrahyoid branch of superior thyroid artery.
r. infrapatellaris nervi sapheni [TA] SYN: infrapatellar branch of saphenous nerve.
rami inguinales arteriarum pudendarum externarum profundarum [TA] SYN: inguinal branches of deep external pudendal arteries, under branch.
rami intercostales anteriores SYN: anterior intercostal branches of internal thoracic artery, under branch.
rami intercostales anteriores arteriae thoracicae internae [TA] SYN: anterior intercostal branches of internal thoracic artery, under branch.
rami interganglionares trunci sympathici [TA] SYN: interganglionic branches of sympathetic trunk, under branch.
r. intermedius arteriae hepaticae propriae [TA] SYN: intermediate branch of hepatic artery proper.
internal r. of accessory nerve SYN: internal branch of trunk of accessory nerve. SEE ALSO: accessory nerve [CN XI].
r. internus trunci nervi accessorii [TA] SYN: internal branch of trunk of accessory nerve. SEE ALSO: accessory nerve [CN XI].
r. internus nervi laryngei superioris [TA] SYN: internal branch of superior laryngeal nerve.
rami interventriculares septales SYN: interventricular septal branches of left/right coronary artery, under branch.
rami interventriculares septales arteriae coronariae sinistrae/dextrae SYN: interventricular septal branches of left/right coronary artery, under branch.
r. interventricularis anterior arteriae coronariae sinistrae [TA] SYN: anterior interventricular branch of left coronary artery.
r. interventricularis posterior arteriae coronariae dextrae [TA] SYN: posterior interventricular branch of right coronary artery.
ischial r. SYN: r. of ischium.
ischiopubic r. the inferior r. of the pubis and the r. of the ischium continuous with it, forming the inferomedial boundary of the obturator foramen.
r. of ischium [TA] the branch of the ischial bone, formerly called inferior branch of the ischium; the portion of the bone that passes forward from the ischial tuberosity to join the inferior r. of the pubic bone, thus forming the ischiopubic r.. SYN: r. ossis ischii [TA] , ischial r..
rami isthmi faucium nervi lingualis [TA] SYN: branches of lingual nerve to isthmus of fauces, under branch.
rami labiales anteriores arteriae pudendae externae profundae [TA] SYN: anterior labial branches of deep external pudendal artery, under branch.
rami labiales inferiores nervi mentalis SYN: labial branches of mental nerve, under branch.
rami labiales nervi mentalis [TA] SYN: labial branches of mental nerve, under branch.
rami labiales posteriores arteriae perinealis [TA] SYN: posterior labial branches of internal perineal artery.
rami labiales posteriores arteriae pudendae internae SYN: posterior labial branches of internal perineal artery.
rami labiales superiores nervi infraorbitalis [TA] SYN: superior labial branches of infraorbital nerve, under branch.
r. labialis inferior arteriae facialis SYN: inferior labial branch of facial artery.
r. labialis superior arteriae facialis SYN: superior labial branch of facial artery.
rami laryngopharyngei ganglii cervicalis superioris [TA] SYN: laryngopharyngeal branches of superior cervical ganglion, under branch.
rami laterales [TA] SYN: lateral branches, under branch.
rami laterales arteriae pontis [TA] SYN: lateral branches of pontine arteries, under branch.
rami laterales arteriarum centralium anterolateralium lateral branch of anterolateral central arteries.
rami laterales arteriarum tuberis cinerei [TA] SYN: lateral branches of artery of tuber cinereum, under branch.
rami laterales rami sinistri venae portae hepatis lateral branch of left branch of portal vein. See lateral branches, under branch.
rami laterales ramorum dorsalium nervorum spinalis lateral branch of dorsal primary rami of spinal nerves. See lateral branches, under branch.
r. lateralis ductus hepatici sinistri lateral branch left hepatic duct. See lateral branches, under branch.
r. lateralis interventricularis anterioris arteriae coronariae sinistrae lateral branch of anterior interventricular artery. See lateral branches, under branch.
r. lateralis nasi arteriae facialis [TA] SYN: lateral nasal branch of facial artery.
r. lateralis nervi supraorbitalis lateral branch of supraorbital nerve. See lateral branches, under branch.
r. lateralis ramorum dorsalium nervorum thoracicorum lateral cutaneous branch of dorsal branch of thoracic nerves.
r. lateralis rami lobaris medii arteriae pulmonalis dextrae lateral branch of middle lobe branch of right pulmonary artery. See lateral branches, under branch.
rami lienales arteriae lienalis splenic branches of splenic artery, under branch.
rami linguales nervi glossopharyngei lingual branch of glossopharyngeal nerve. See lingual branches, under branch.
rami linguales nervi hypoglossi lingual branch of hypoglossal nerve. See lingual branches, under branch.
rami linguales nervi lingualis lingual branch of lingual nerve. See lingual branches, under branch.
rami linguales SYN: lingual branches, under branch.
r. lingualis nervi facialis SYN: lingual branch of facial nerve.
r. lingularis inferior SYN: inferior lingular artery.
r. lingularis superior SYN: superior lingular artery.
r. lingularis venae pulmonis sinistrae superioris lingular vein.
rami lobi caudati rami sinistri venae portae hepatis [TA] SYN: caudate branches of left branch of portal vein, under branch.
r. lobi medii arteriae pulmonalis dextrae middle lobe branch of right pulmonary artery. See middle lobe vein.
r. lobi medii venae pulmonalis dextrae superioris SYN: middle lobe vein. See middle lobe vein.
r. lumbalis arteriae iliolumbalis [TA] SYN: lumbar branch of iliolumbar artery.
rami malleolares laterales arteriae fibularis (peronei) [TA] SYN: lateral malleolar branch (of fibular peroneal artery).
rami malleolares mediales arteriae tibialis posterioris [TA] SYN: medial malleolar branches (of posterior tibial artery), under branch.
rami mammarii See lateral mammary branches, under branch, medial mammary branches, under branch.
rami mammarii laterales SYN: lateral mammary branches, under branch.
rami mammarii laterales arteriae thoracicae lateralis [TA] SYN: lateral mammary branches of lateral thoracic artery, under branch.
rami mammarii laterales ramorum cutaneorum lateralium nervorum intercostalium SYN: lateral mammary branches of lateral cutaneous branches of thoracic spinal nerves, under branch.
rami mammarii laterales ramorum cutaneorum lateralis nervorum thoracicorum SYN: lateral mammary branches of lateral cutaneous branches of thoracic spinal nerves, under branch.
rami mammarii mediales SYN: medial mammary branches, under branch.
rami mammarii mediales ramorum cutaneorum anteriorum nervorum intercostalium medial mammary branches of anterior cutaneous branches of ventral primary rami of thoracic spinal nerves. See medial mammary branches, under branch.
rami mammarii mediales rami cutanei anterioris ramorum ventralium nervorum thoracicorum medial mammary branches of anterior cutaneous branches of ventral primary rami of thoracic spinal nerves. See medial mammary branches, under branch.
rami mammarii mediales ramorum perforantium arteriae thoracicae internae medial mammary branches of perforating branches of internal thoracic artery. See medial mammary branches, under branch.
r. of mandible [TA] the upturned perpendicular extremity of the mandible on either side; it gives attachment on its lateral surface to the masseter muscle. SYN: r. mandibulae [TA] .
r. mandibulae [TA] SYN: r. of mandible.
r. marginalis [TA] SYN: marginal sulcus.
r. marginalis dexter (arteriae coronariae dextrae) [TA] SYN: right marginal branch (of right coronary artery).
r. marginalis mandibulae nervi facialis [TA] SYN: marginal mandibular branch of facial nerve.
r. marginalis sinister arteriae coronariae sinistrae [TA] SYN: left marginal artery.
r. marginalis sulci cinguli [TA] SYN: marginal branch of cingulate sulcus.
r. marginalis sulci parietooccipitalis [TA] SYN: marginal branch of parietooccipital sulcus.
r. marginalis tentorii arteriae carotidis internae SYN: tentorial marginal branch of cavernous part of internal carotid artery.
r. marginalis tentorii partis cavernosae arteriae carotidis internae [TA] SYN: tentorial marginal branch of cavernous part of internal carotid artery.
rami mastoidei arteriae auricularis posterioris SYN: mastoid branches of posterior tympanic artery, under branch.
rami mastoidei arteriae tympanicae posterioris [TA] SYN: mastoid branches of posterior tympanic artery, under branch.
r. mastoideus arteriae occipitalis [TA] SYN: mastoid branch of occipital artery.
r. meatus acustici interni SYN: labyrinthine artery.
rami mediales [TA] SYN: medial branches, under branch.
rami mediales arteriae pontis [TA] SYN: medial branches of pontine arteries, under branch.
rami mediales arteriarum centralium anterolateralium medial branch of anterolateral central arteries. See medial branches, under branch.
rami mediales arteriarum tuberis cinerei [TA] SYN: medial branches of artery of tuber cinereum, under branch.
r. medialis ductus hepatici sinistri medial branch of left hepatic duct. See medial branches, under branch.
r. medialis nervi supraorbitalis medial branch of supraorbital nerve. See medial branches, under branch.
r. medialis rami lobaris medii arteriae pulmonalis dextrae medial branch of middle lobar branch of right pulmonary artery. See medial branches, under branch.
rami mediales rami sinistri venae portae hepatis medial branch of left branch of portal vein. See medial branches, under branch.
r. medialis ramorum dorsalium nervorum spinalis SYN: medial branch of posterior rami of spinal nerves. See medial branches, under branch.
rami mediastinales [TA] SYN: mediastinal branches, under branch.
rami mediastinales aortae thoracicae [TA] SYN: mediastinal branches of thoracic aorta, under branch.
rami mediastinales arteriae thoracicae internae [TA] SYN: mediastinal branches of internal thoracic artery, under branch.
rami medullares laterales lateral medullary branches [TA], branches of the posterior inferior cerebellar artery to the lateral part of the medulla oblongata.
rami medullares laterales (partis intracranialis) arteriae vertebralis [TA] SYN: lateral medullary branches of (intracranial part of) vertebral artery, under branch.
rami medullares mediales medial medullary branches [TA], branches of the posterior inferior cerebellar artery to the medial part of the medulla oblongata.
rami medullares mediales arteriae vertebralis [TA] SYN: medial medullary branches of vertebral artery, under branch.
rami membranae tympani nervi auriculotemporalis [TA] SYN: branches of auriculotemporal nerve to tympanic membrane, under branch.
rami meningei [TA] SYN: meningeal branches, under branch.
r. meningeus accessorius SYN: pterygomeningeal artery.
r. meningeus accessorius arteriae meningeae mediae SYN: accessory branch of middle meningeal artery.
r. meningeus anterior arteriae ethmoidalis anterioris [TA] SYN: anterior meningeal branch (of anterior ethmoidal artery).
r. meningeus anterior arteriae vertebralis meningeal branch of the vertebral artery.
r. meningeus arteriae carotidis internae SYN: meningeal branch of cavernous part of internal carotid artery.
r. meningeus arteriae occipitalis [TA] SYN: meningeal branch of occipital artery.
r. meningeus medius nervi maxillaris SYN: meningeal branch of maxillary nerve.
r. meningeus nervi mandibularis [TA] SYN: meningeal branch of mandibular nerve.
r. meningeus nervi maxillaris [TA] SYN: meningeal branch of maxillary nerve.
r. meningeus nervi vagi [TA] SYN: meningeal branch of vagus nerve.
r. meningeus nervorum spinalium [TA] SYN: meningeal branch of spinal nerves.
r. meningeus partis cavernosae arteriae carotidis internae [TA] SYN: meningeal branch of cavernous part of internal carotid artery.
r. meningeus partis cerebralis arteriae carotidis internae [TA] SYN: meningeal branch of cerebral part of internal carotid artery.
r. meningeus (partis intracranialis) arteriae vertebralis [TA] SYN: meningeal branch of (intracranial part of) vertebral artery.
r. meningeus posterior the posterior meningeal branch of the vertebral artery.
r. meningeus recurrens nervi ophthalmici [TA] SYN: tentorial nerve.
rami mentales nervi mentalis [TA] SYN: mental branches of mental nerve, under branch.
r. mentalis arteriae alveolaris inferioris [TA] SYN: mental branch (of inferior alveolar artery).
rami musculares [TA] SYN: muscular branches, under branch.
rami musculares arteriae vertebralis [TA] See muscular branches, under branch.
rami musculares nervi accessorii [TA] See muscular branches, under branch.
rami musculares nervi axillaris [TA] See muscular branches, under branch.
rami musculares nervi fibularis profundi [TA] See muscular branches, under branch.
rami musculares nervi fibularis superficialis [TA] See muscular branches, under branch.
rami musculares nervi interossei antebrachii anterior [TA] See muscular branches, under branch.
rami musculares nervi mediani [TA] See muscular branches, under branch.
rami musculares nervi musculocutanei [TA] See muscular branches, under branch.
rami musculares nervi radialis [TA] See muscular branches, under branch.
rami musculares nervi tibialis [TA] See muscular branches, under branch.
rami musculares nervi ulnaris [TA] See muscular branches, under branch.
rami musculares nervorum intercostalium [TA] See muscular branches, under branch.
rami musculares nervorum perinealium [TA] See muscular branches, under branch.
rami musculares nervorum spinalium [TA] See muscular branches, under branch.
rami musculares partis supraclavicularis plexus brachialis [TA] See muscular branches, under branch.
rami musculares rami anterioris nervi obturatorii [TA] See muscular branches, under branch.
rami musculares rami posterioris nervi obturatorii [TA] See muscular branches, under branch.
r. musculi stylopharyngei nervi glossopharyngei [TA] SYN: stylopharyngeal branch of glossopharyngeal nerve.
r. mylohyoideus arteriae alveolaris inferioris [TA] SYN: mylohyoid branch (of inferior alveolar artery).
rami nasales anteriores laterales arteriae ethmoidalis anterioris [TA] SYN: anterior lateral nasal branches of anterior ethmoidal artery, under branch.
rami nasales externi nervi ethmoidalis anterioris external nasal branch of nasociliary nerve; See external nasal branches of infraorbital nerve, under branch.
rami nasales externi nervi infraorbitalis SYN: external nasal branches of infraorbital nerve, under branch. See external nasal branches of infraorbital nerve, under branch.
rami nasales interni [TA] SYN: internal nasal branches, under branch.
rami nasales interni nervi ethmoidalis anterioris internal nasal branch of nasociliary nerve. See internal nasal branches, under branch.
rami nasales interni nervi infraorbitalis internal nasal branch of infraorbital nerve. See internal nasal branches, under branch.
rami nasales laterales nervi ethmoidalis anterioris [TA] SYN: lateral nasal branches of anterior ethmoidal nerve, under branch.
rami nasales mediales nervi ethmoidalis anterioris [TA] SYN: medial nasal branches of anterior ethmoidal nerve, under branch.
rami nasales posteriores inferiores nervi palatini majoris [TA] SYN: posterior inferior nasal nerves, under nerve.
rami nasales posteriores superiores laterales ganglii pterygopalatini SYN: posterior superior lateral nasal branches of maxillary nerve, under branch.
rami nasales posteriores superiores laterales nervi maxillaris SYN: posterior superior lateral nasal branches of maxillary nerve, under branch.
rami nasales posteriores superiores mediales ganglii pterygopalatini SYN: posterior superior medial nasal branches of maxillary nerve, under branch.
rami nasales posteriores superiores mediales nervi maxillaris [TA] SYN: posterior superior medial nasal branches of maxillary nerve, under branch.
r. nervi oculomotorii arteriae communicantis posterioris the branch to the oculomotor nerve, a branch of the posterior communicating artery to the oculomotor nerve.
r. nodi atrioventricularis [TA] SYN: atrioventricular nodal branch.
r. nodi sinuatrialis arteriae coronariae dextrae [TA] SYN: sinuatrial (S-A) nodal branch of right coronary artery.
rami nucleorum hypothalamicorum [TA] branches to hypothalamic nuclei [TA], branches of the anterior choroid artery to the nuclei of the hypothalamus.
r. obturatorius arteriae epigastricae inferioris SYN: accessory obturator artery.
r. obturatorius rami pubici arteriae epigastricae inferioris [TA] SYN: obturator branch of pubic branch of inferior epigastric vein.
rami occipitales arteriae auricularis posterioris occipital branch of posterior auricular artery. See occipital branch.
rami occipitales arteriae occipitis occipital branch of occipital artery. See occipital branch.
rami occipitales nervi auricularis posterioris occipital branch posterior auricular nerve. See occipital branch.
r. occipitalis [TA] SYN: occipital branch.
r. occipitotemporalis [TA] occipitotemporal branch [TA], a branch of the medial occipital artery to the occipital and temporal regions of the cerebral cortex.
rami omentales [TA] SYN: omental branches, under branch.
rami orbitales nervi maxillaris [TA] SYN: orbital branches of maxillary nerve, under branch.
r. orbitalis arteriae meningeae mediae [TA] SYN: orbital branch of middle meningeal artery.
r. orbitalis ganglii pterygopalatini SYN: orbital branches of maxillary nerve, under branch.
r. ossis ischii [TA] SYN: r. of ischium.
rami ovarici arteriae uterinae [TA] SYN: ovarian branches of uterine artery, under branch.
r. palmaris nervi interossei antebrachii anterioris [TA] SYN: palmar branch of anterior interosseous nerve.
r. palmaris nervi mediani SYN: palmar branch of anterior interosseous nerve.
r. palmaris nervi ulnaris [TA] SYN: palmar branch of ulnar nerve.
r. palmaris profundus arteriae ulnaris [TA] SYN: deep palmar branch of ulnar artery.
r. palmaris superficialis arteriae radialis [TA] SYN: superficial palmar branch of radial artery.
rami palpebrales nervi infratrochlearis [TA] SYN: palpebral branches of infratrochlear nerve, under branch.
rami pancreatici [TA] SYN: pancreatic branches, under branch.
rami pancreatici arteriae pancreaticoduodenalis superioris pancreatic branch of superior pancreaticoduodenal arteries. See pancreatic branches, under branch.
rami pancreatici arteriae splenicae pancreatic branch splenic artery. See pancreatic branches, under branch.
r. paracentrales [TA] SYN: paracentral branches (of pericallosal artery), under branch.
rami paracentrales arteriae callosomarginalis [TA] SYN: paracentral branches of callosomarginal artery, under branch.
rami parietales [TA] SYN: parietal branch.
r. parietalis arteriae meningeae mediae [TA] SYN: parietal branch of middle meningeal artery.
r. parietalis arteriae occipitalis medialis [TA] SYN: parietal branch of medial occipital artery.
r. parietalis arteriae temporalis superficialis [TA] SYN: parietal branch of superficial temporal artery.
r. parieto-occipitalis [TA] parieto-occipital branch [TA] of medial occipital artery.
r. parieto-occipitalis arteriae occipitalis medialis [TA] SYN: parieto-occipital branch (of posterior cerebral artery).
rami parotidei [TA] SYN: parotid branches, under branch.
r. parotidei arteriae temporalis superficialis parotid branch of superficial temporal artery. See parotid branches, under branch.
rami parotidei nervi auriculotemporalis parotid branch of auriculotemporal nerve. See parotid branches, under branch.
rami parotidei venae facialis parotid branch of facial vein. See parotid branches, under branch.
rami partis retrolentiformis capsulae internae [TA] SYN: rami capsulae internae.
rami pectorales arteriae thoracoacromialis [TA] SYN: pectoral branch of thoracoacromial artery, under branch.
rami pedunculares [TA] peduncular branches [TA], branches of the posterior cerebral artery to the cerebral peduncles.
r. perforans [TA] SYN: perforating branches, under branch.
r. perforans arteriae fibularis [TA] SYN: perforating branch of fibular artery.
r. perforans arteriae interossei anterioris [TA] SYN: perforating branch of anterior interosseous artery.
rami perforantes arcus palmaris profundi [TA] SYN: perforating branches of deep palmar arch.
rami perforantes arteriae thoracicae internae [TA] SYN: perforating branches of internal thoracic artery, under branch.
rami perforantes arteriarum metacarpalium palmarium See perforating branches of deep palmar arch.
rami perforantes arteriarum metatarsearum plantarium [TA] SYN: perforating branches (of plantar metatarsal arteries), under branch.
rami pericardiaci aortae thoracicae [TA] SYN: pericardial branch of thoracic aorta, under branch.
r. pericardiacus nervi phrenici [TA] SYN: pericardial branch of phrenic nerve.
rami perineales nervi cutanei femoris posterioris [TA] SYN: perineal branches of posterior cutaneous nerve of thigh, under branch.
peroneal anastomotic r. SYN: sural communicating branch of common fibular nerve.
r. petrosus arteriae meningeae mediae [TA] SYN: petrosal branch of middle meningeal artery.
rami pharyngeales pharyngeal branches, under branch.
rami pharyngeales arteriae pharyngeae ascendentis [TA] SYN: pharyngeal branch of the ascending pharyngeal artery.
rami pharyngeales arteriae thyroideae inferioris [TA] SYN: pharyngeal branch of inferior thyroid artery.
rami pharyngei [TA] SYN: pharyngeal branches, under branch.
rami pharyngei nervi glossopharyngei [TA] SYN: pharyngeal branch of glossopharyngeal nerve.
rami pharyngei nervi laryngei recurrentis [TA] SYN: pharyngeal branches of recurrent laryngeal nerve, under branch.
rami pharyngei nervi vagi [TA] SYN: pharyngeal branch of vagus nerve.
r. pharyngeus arteriae canalis pterygoidei [TA] SYN: pharyngeal branch of the artery of pterygoid canal.
r. pharyngeus arteriae palatinae descendentis [TA] SYN: pharyngeal branch of descending palatine artery.
r. pharyngeus ganglii pterygopalatini SYN: pharyngeal nerve.
rami phrenicoabdominales nervi phrenici SYN: phrenicoabdominal branches of phrenic nerve, under branch.
r. plantaris profundus arteriae dorsalis pedis SYN: deep plantar artery.
r. posterior arteriae obturatoriae [TA] SYN: posterior branch of obturator artery.
r. posterior arteriae pancreaticoduodenalis inferioris [TA] SYN: posterior branch of inferior pancreaticoduodenal artery.
r. posterior arteriae recurrentis ulnaris [TA] SYN: posterior branch of ulnar recurrent artery.
r. posterior arteriae renalis [TA] SYN: posterior branch of renal artery. See segmental arteries of kidney, under artery.
r. posterior arteriae thyroideae superioris SYN: posterior glandular branch of superior thyroid artery.
r. posterior descendens SYN: descending branch of posterior segmental artery of left and right lungs.
r. posterior ductus hepatici dextri [TA] SYN: posterior branch of right hepatic duct.
rami posteriores [TA] SYN: posterior branches, under branch.
r. posterior nervi spinalis [TA] SYN: posterior r. of spinal nerve.
posterior r. of lateral cerebral sulcus [TA] the long, posteriorly-directed continuation of the lateral cerebral sulcus which extends between the temporal lobe inferiorly and the parietal lobe superiorly, its termination surrounded by the supramarginal gyrus. SYN: posterior branch of lateral cerebral sulcus, r. posterior sulci lateralis cerebri.
posterior r. of lateral sulcus of cerebrum [TA] SYN: r. posterior sulcus lateralis cerebri [TA] .
r. posterior nervi auricularis magni [TA] SYN: posterior branch of great auricular nerve.
r. posterior nervi cutanei antebrachii medialis [TA] SYN: posterior branch of medial cutaneous nerve of forearm.
r. posterior nervi obturatorii [TA] SYN: posterior branch of obturator nerve.
r. posterior rami dextri venae portae hepatis [TA] SYN: posterior branch of right branch of portal vein.
posterior r. of spinal nerve [TA] the smaller, posteriorly directed major terminal branch (with the anterior r.) of all 31 pairs of mixed spinal nerves, formed at the intervertebral foramen and turning abruptly posteriorly to divide into lateral and medial branches, both of which will supply the deep (true) muscles of the back. The medial branch (rami medialis [TA]) of the dorsal primary r. also supplies articular branches to the zygapophyseal joints and the periosteum of the vertebral arch. In the neck and upper back, the medial branch continues through the deep and superficial back muscles to supply overlying skin; in the lower back, the lateral branch does this. Terminologia Anatomica lists posterior rami (rami dorsales) for each group of spinal nerves: 1) cervical (nervorum cervicalium [TA]), 2) thoracic (nervorum thoracicorum [TA]), 3) lumbar (nervorum lumbalium [TA]), 4) sacral (nervorum sacralium [TA]), and 5) coccygeal (nervi coccygei [TA]). SYN: r. posterior nervi spinalis [TA] , dorsal primary r. of spinal nerve&star, r. dorsalis nervi spinalis&star, dorsal branch (1) , posterior primary division, r. dorsalis.
r. posterior sulci lateralis cerebri SYN: posterior r. of lateral cerebral sulcus.
r. posterior sulcus lateralis cerebri [TA] SYN: posterior r. of lateral sulcus of cerebrum.
r. posterior venae pulmonalis dextrae superioris [TA] SYN: posterior branch of right superior pulmonary vein.
rami precuneales arteriae cerebri anterioris [TA] SYN: precuneal branches (of anterior cerebral artery), under branch.
r. prelaminaris rami spinalis rami dorsalis arteriae intercostalis posterioris [TA] SYN: prelaminar branch of spinal branch of dorsal branch of posterior intercostal artery.
rami profundi arteriae transversae cervicis [TA] SYN: dorsal scapular artery.
r. profundus [TA] SYN: deep branch.
r. profundus arteriae circumflexae femoris medialis [TA] SYN: deep branch of the medial circumflex femoral artery.
r. profundus arteriae gluteae superioris [TA] SYN: deep branch of the superior gluteal artery.
r. profundus arteriae plantaris medialis [TA] SYN: deep branch of the medial plantar artery.
r. profundus arteriae scapularis descendentis SYN: dorsal scapular artery.
r. profundus arteriae transversae colli [TA] SYN: dorsal scapular artery.
r. profundus nervi plantaris lateralis [TA] SYN: deep branch of the lateral plantar nerve.
r. profundus nervi radialis [TA] SYN: deep branch of radial nerve.
r. profundus nervi ulnaris [TA] SYN: deep branch of the ulnar nerve.
rami prostatici arteriae rectalis mediae [TA] SYN: prostatic branches of middle rectal artery, under branch.
rami prostatici arteriae vesicalis inferioris [TA] SYN: prostatic branches of inferior vesical artery, under branch.
rami pterygoidei arteriae maxillaris SYN: pterygoid branch of posterior deep temporal artery.
r. pterygoideus arteriae temporalis profundae posterioris [TA] SYN: pterygoid branch of posterior deep temporal artery.
pubic rami pubic hair.
r. pubicus arteriae epigastricae inferioris [TA] SYN: pubic branch of inferior epigastric artery.
r. pubicus arteriae obturatoriae [TA] SYN: pubic branch of obturator artery.
r. pubicus venae epigastricae inferioris [TA] SYN: pubic branch of inferior epigastric vein.
rami pulmonales plexi nervosi pulmonalis [TA] SYN: pulmonary branches of pulmonary nerve plexus, under branch.
rami pulmonales systematis autonomici SYN: pulmonary branch of autonomic nervous system, under branch.
rami pulmonales thoracici gangliorum thoracicorum [TA] SYN: thoracic pulmonary branches of thoracic ganglia, under branch.
r. pyloricus trunci vagalis anterioris [TA] SYN: pyloric branch of anterior vagal trunk.
rami radiculares SYN: spinal arteries, under artery.
r. atrialis intermedius arteriae coronariae sinistrae [TA] SYN: intermediate atrial branch of left coronary artery.
rami renales nervi vagi [TA] SYN: renal branch of vagus nerve, under branch.
r. renalis nervi splanchnici minoris [TA] SYN: renal branch of lesser splanchnic nerve.
rami sacrales laterales arteriae sacralis medianae [TA] SYN: lateral sacral branches of median sacral artery, under branch.
r. saphenus arteriae descendentis genicularis [TA] SYN: saphenous branch of descending genicular artery.
rami scrotales anteriores arteriae pudendae externae profundae [TA] SYN: anterior scrotal branch of deep external pudendal artery.
rami scrotales posteriores arteriae perinealis [TA] SYN: posterior scrotal branches of perineal artery, under branch.
rami scrotales posteriores arteriae pudendae internae SYN: posterior scrotal branches of perineal artery, under branch.
rami septales rami interventricularis septales.
rami septales anteriores arteriae ethmoidalis anterioris [TA] SYN: anterior septal branches of anterior ethmoidal artery, under branch.
r. septi nasi arteriae labialis superioris [TA] SYN: nasal septal branch of superior labial branch of facial artery.
r. septi posterioris nasalis [TA] SYN: posterior septal branch of nose.
r. sinister [TA] SYN: left branch.
r. sinister arteriae hepaticae propriae [TA] SYN: left branch of hepatic artery proper.
r. sinister venae portae hepatis left branch of hepatic portal vein.
r. sinus carotici [TA] SYN: carotid branch of glossopharyngeal nerve (CN IX).
r. sinus carotici nervi glossopharyngei CN IX [TA] SYN: carotid branch of glossopharyngeal nerve (CN IX).
r. sinus cavernosi the cavernous sinus branch, a branch of the cavernous part of the internal carotid artery supplying the walls of the cavernous sinus.
r. sinus cavernosi arteriae carotidis arteriae SYN: cavernous branch of cavernous part of internal carotid artery.
r. sinus cavernosi arteriae carotidis internae SYN: cavernous branch of cavernous part of internal carotid artery.
r. sinus cavernosi partis cavernosae arteriae carotidis internae [TA] SYN: cavernous branch of cavernous part of internal carotid artery.
rami spinales [TA] spinal branches 1. SYN: spinal branches, under branch. 2. veins draining the meninges and spinal cord, tributaries of the intervertebral veins.
rami splenici arteriae splenicae [TA] SYN: splenic branches of splenic artery, under branch.
r. stapedius arteriae stylomastoideae SYN: stapedial branch of posterior tympanic artery.
r. stapedius arteriae tympanicae posterioris [TA] SYN: stapedial branch of posterior tympanic artery.
rami sternales arteriae thoracicae internae [TA] SYN: sternal branches of internal thoracic artery, under branch.
rami sternocleidomastoidei arteriae occipitalis SYN: sternocleidomastoid branches of occipital artery, under branch.
r. sternocleidomastoideus arteriae thyroideae superioris [TA] SYN: sternocleidomastoid branch of superior thyroid artery.
r. stylohyoideus nervi facialis [TA] SYN: stylohyoid branch of facial nerve.
rami subendocardiales fasciculi atrioventricularis [TA] SYN: subendocardial branches of atrioventricular bundles, under branch.
rami subscapulares arteriae axillaris [TA] SYN: subscapular branches of axillary artery, under branch.
rami substantiae nigrae [TA] branches to substantia nigra [TA], the branches of the anterior choroid artery to the substantia nigra.
r. superficialis [TA] SYN: superficial branch.
r. superficialis arteriae circumflexae femoris medialis [TA] SYN: superficial branch of medial circumflex femoral artery.
r. superficialis arteriae gluteae superioris [TA] SYN: superficial branch of the superior gluteal artery.
r. superficialis arteriae plantaris medialis [TA] SYN: superficial branch of the medial plantar artery.
r. superficialis arteriae transversae cervicis [TA] SYN: superficial cervical artery.
r. superficialis arteriae transversae colli [TA] SYN: superficial branch of the transverse cervical artery.
r. superficialis nervi plantaris lateralis [TA] SYN: superficial branch of the lateral plantar nerve.
r. superficialis nervi radialis [TA] SYN: superficial branch of the radial nerve.
r. superficialis nervi ulnaris [TA] SYN: superficial branch of the ulnar nerve.
r. superior [TA] SYN: superior branch.
r. superior arteriae gluteae superioris [TA] SYN: superior branch of the superior gluteal artery.
superior dental rami SYN: superior dental branches of superior dental plexus, under branch.
r. superior nervi oculomotorii [TA] SYN: superior branch of the oculomotor nerve.
r. superior nervi transversalis cervicalis (colli) [TA] SYN: superior branch of the transverse cervical nerve.
r. superior ossis pubis [TA] SYN: superior pubic r..
superior pubic r. [TA] a bar of bone, triangular in section, which extends posterosuperiorly from the body of the pubis to form the superior boundary of the obturator foramen; developmentally, it contributes about one-fifth of the articular surface of the acetabulum. SYN: r. superior ossis pubis [TA] , superior branch of the pubic bone.
r. superior venae pulmonalis dextrae/sinistrae inferioris SYN: superior branch of the right and left inferior pulmonary veins.
r. suprahyoideus arteriae lingualis [TA] SYN: suprahyoid branch of lingual artery.
r. sympathicus (sympatheticus) ad ganglion submandibulare SYN: sympathetic root of submandibular ganglion.
rami temporales anteriores [TA] anterior temporal branches [TA] of lateral occipital artery, giving arterial supply to the cortex of the anterior part of the temporal lobe of the brain.
rami temporales intermedii [TA] intermediate temporal branches [TA] of lateral occipital artery, giving arterial supply to the cortex of the intermediate and medial part of the temporal lobe of the brain.
rami temporales intermedii arteriae occipitalis lateralis [TA] SYN: intermediate temporal branches of lateral occipital artery, under branch.
rami temporales medii arteriae occipitalis lateralis intermediate temporal branches of lateral occipital artery, under branch.
rami temporales nervi facialis [TA] SYN: temporal branch of facial nerve, under branch.
rami temporales posteriores [TA] posterior temporal branches [TA] of lateral occipital artery giving arterial supply to the cortex of the posterior part of the temporal lobe of the brain.
rami temporales superficiales nervi auriculotemporalis [TA] SYN: superficial temporal branch of auriculotemporal nerve, under branch.
r. temporalis anterior [TA] SYN: anterior temporal branch.
r. temporalis medius partis insularis arteriae cerebrae mediae [TA] SYN: middle temporal branch of insular part of middle cerebral artery.
r. temporalis posterior arteriae cerebri mediae [TA] SYN: posterior temporal branch of middle cerebral artery.
r. tentorii tentorial nerve.
rami terminales arteriae cerebri medii [TA] SYN: terminal branches of middle cerebral artery, under branch.
rami thalamici branches of the posterior cerebral artery to the thalamus, such as the thalamoperforating and thalamogeniculate arteries.
r. thalamicus a branch of the middle cerebral artery to the thalamus.
rami thymici SYN: mediastinal branches of internal thoracic artery, under branch.
rami thymici arteriae thoracicae internae [TA] SYN: thymic branches of internal thoracic artery, under branch.
r. thyrohyoideus ansae cervicalis [TA] SYN: thyrohyoid branch of ansa cervicalis.
r. tonsillae cerebellae [TA] cerebellar tonsillar branch [TA], the branch to the cerebellar tonsil, a branch from the posterior inferior cerebellar artery supplying the tonsil of the cerebellum.
rami tonsillares nervi glossopharyngei SYN: tonsillar branches of glossopharyngeal nerve, under branch.
rami tonsillares nervi palatini minores [TA] SYN: tonsillar branches of lesser palatine nerves, under branch.
r. tonsillaris arteriae facialis [TA] SYN: tonsillar branch of the facial artery.
rami tracheales [TA] SYN: tracheal branches, under branch.
rami tracheales arteriae thyroideae inferioris tracheal branches of inferior thyroid artery. See tracheal branches, under branch.
rami tracheales nervi laryngei recurrentis tracheal branches of recurrent laryngeal nerve. See tracheal branches, under branch.
rami tractus optici [TA] branches to optic tract [TA] branches, branches of the anterior choroid artery to the optic tract.
r. transversus arteriae circumflexae femoris lateralis [TA] SYN: transverse branch of lateral femoral circumflex artery.
r. transversus arteriae circumflexae femoris medialis transverse branches of medial femoral circumflex artery.
r. tubarius [TA] SYN: tubal branch.
r. tubarius arteriae ovaricae [TA] SYN: tubal branch of ovarian artery.
r. tubarius arteriae uterinae [TA] SYN: tubal branch of the uterine artery.
r. tubarius plexus tympanici [TA] SYN: tubal branch of the tympanic plexus.
rami tuberis cinerei [TA] branches to tuber cinereum [TA], the branches of the anterior choroid artery to the tuber cinereum.
r. ulnaris nervi cutanei antebrachii medialis SYN: posterior branch of medial cutaneous nerve of forearm.
rami ureterici [TA] SYN: ureteric branches, under branch.
rami ureterici arteriae ovaricae [TA] SYN: ureteric branches of the ovarian artery, under branch.
rami ureterici arteriae renalis SYN: ureteric branches of the renal artery, under branch.
rami ureterici arteriae suprarenalis inferioris [TA] SYN: ureteric branches of the inferior suprarenal artery, under branch.
rami ureterici arteriae testicularis [TA] SYN: ureteric branches of the testicular artery, under branch.
rami ureterici partis patentis arteriae umbilicalis [TA] SYN: ureteric branches of the patent part of umbilical artery, under branch.
ventral rami of cervical nerves anterior rami of cervical nerves.
rami ventrales nervorum thoracis anterior rami of thoracic nerves.
rami ventrales nervorum cervicalium SYN: anterior rami of cervical nerves. See anterior r. of spinal nerve.
rami ventrales nervorum lumbalium SYN: anterior rami of lumbar nerves. See anterior r. of spinal nerve.
rami ventrales nervorum sacralium SYN: anterior rami of sacral nerves. See anterior r. of spinal nerve.
r. ventralis SYN: ventral branch.
r. ventralis nervi spinalis anterior r. of spinal nerve.
ventral rami of lumbar nerves anterior rami of lumbar nerves.
ventral primary rami of cervical spinal nerves SYN: anterior rami of cervical nerves.
ventral primary rami of lumbar spinal nerves SYN: anterior rami of lumbar nerves.
ventral primary rami of sacral spinal nerves SYN: anterior rami of sacral nerves. See anterior r. of spinal nerve.
ventral primary r. of spinal nerve SYN: anterior r. of spinal nerve.
ventral primary rami of thoracic spinal nerves SYN: anterior rami of thoracic nerves.
ventral rami of sacral nerves anterior rami of sacral nerves.
ventral r. of spinal nerve anterior r. of spinal nerve.
ventral rami of thoracic nerves anterior rami of thoracic nerves.
r. vermis superior [TA] SYN: superior vermian branch (of superior cerebellar artery).
rami vestibulares arteriae labyrinthi vestibular branches of labyrinthine artery.
r. vestibularis posterior arteriae vestibulocochlearis [TA] SYN: posterior vestibular branch of vestibulocochlear artery.
white rami communicantes [TA] short nerves arising from the initial portion of the ventral primary rami of the thoracic and upper lumbar spinal nerves through which all presynaptic sympathetic nerve fibers must pass to reach the sympathetic trunks; also conveyed by the white rami communicans are visceral afferent (sensory) fibers that were conveyed to the sympathetic trunks in splanchnic nerves. Most fibers conveyed by the white rami communicantes are myelinated. SYN: rami communicantes albi [TA] , communicating branches of spinal nerves, rami communicantes nervorum spinalium.
rami zygomatici nervi facialis SYN: zygomatic branches of facial nerve, under branch.
r. zygomaticofacialis nervi zygomatici [TA] SYN: zygomaticofacial branch of zygomatic nerve.
r. zygomaticotemporalis nervi zygomatici [TA] SYN: zygomaticotemporal branch of zygomatic nerve.

ramycin
ramycin (ra-mi′sin)

SYN: fusidic acid.

rancid
rancid (ran′sid)

Having a disagreeable odor and taste, usually characterizing fat undergoing oxidation or bacterial decomposition to more volatile odoriferous substances. [L. rancidus, stinking, rank]

rancidify
rancidify (ran-sid′i-fi)

To make or become rancid.

rancidity
rancidity (ran-sid′i-te)

The state of being rancid.

Rand
Rand

Gertrude, U.S. visual psychologist, 1886–1970. See Hardy-R.-Ritter test.

Rand
Rand

M.J., 20th century pharmacologist. See Burn and R. theory.

Randall
Randall

Alexander, U.S. urologist, *1883. See R. stone forceps.

random
random (ran′dom)

Governed by chance; used of a process in which the outcome is indeterminate but may assume any of a set of values (the domain) with probabilities specifiable in advance. While the r. process is widely used in probability theory, empiric justification for the term is more complicated. The minimum requirement is that repeated realization of the process will settle down to a stable distribution or, if not metrical, a stable set of frequencies if the trait is classifiable only. See r. mechanism. [M.E. randon, speed, errancy, fr. O. Fr. randir, to run, fr. Germanic]

randomization
randomization

Allocation of individuals to groups, e.g., for experimental and control regimens, by chance.

Raney Nickel
Raney Nickel

Proprietary name for a finely powdered nickel catalyst made from Raney alloy by dissolving out the aluminum with alkali; used in the hydrogenation of organic substances. SYN: Raney catalyst.

range
range (ranj)

A statistical measure of the dispersion or variation of values determined by the endpoint values themselves or the difference between them; e.g., in a group of children aged 6, 8, 9, 10, 13, and 16, the r. would be from 6 to 16 or, alternately, 10 (16 minus 6). [O.Fr. rang, line fr. Germanic]
therapeutic r. refers to either the dosage r. or blood plasma or serum concentration usually expected to achieve desired therapeutic effects. Some patients will require doses (or concentrations) above or below this r.. Some patients will experience drug toxicity within this r..

ranine
ranine (ra′nin)

1. Relating to the frog. 2. Relating to the undersurface of the tongue. [L. rana, a frog]

ranitidine
ranitidine (ra-ni′ti-den)

A histamine H₂ antagonist used in the treatment of duodenal and gastric ulcers and gastroesophageal reflux, where it reduces hydrochloric acid secretion.

rank
rank

1. The ordinal position of an observation in the set of observations of which it is a member. 2. To order a set of observations according to their r..

Ranke
Ranke

Karl E. von, German chemist, 1870–1926. See R. formula.

Ranke
Ranke

Johannes, German anthropologist and physician, 1836–1916. See R. angle.

Rankin
Rankin

Fred Wharton, U.S. surgeon, 1886–1954. See R. clamp.

Rankine
Rankine

William J. McQ., Scottish physicist, 1820–1870. See R. scale.

Ransohoff
Ransohoff

Joseph, U.S. surgeon, 1853–1921. See R. sign.

RANTES
RANTES

A member of the interleukin-8 superfamily of cytokines. This cytokine is an 8-kD protein that is a selective chemoattractant for memory T lymphocytes and monocytes. [Regulated on activation, normal T expressed and secreted]

ranula
ranula (ran′u-la)

1. Hypoglottis. 2. Obsolete term for any cystic tumor of the undersurface of the tongue or floor of the mouth, especially one of the floor of the mouth due to obstruction of the duct of the sublingual glands. SYN: ptyalocele, ranine tumor, sialocele, sublingual cyst. [L. tadpole, dim. of rana, frog]

ranular
ranular (ran′u-lar)

Relating to a ranula.

Ranvier
Ranvier

Louis A., French pathologist, 1835–1922. See R. crosses, under cross, R. disks, under disk, node of R., R. plexus, R. segment.

RAO
RAO

Abbreviation for right anterior oblique, a radiographic projection.

Raoult
Raoult

François, M., French physicist, 1830–1899. See R. law.

RAPD
RAPD

Abbreviation for rapid analysis of polymorphic DNA.

rape
rape (rap)

1. Sexual intercourse by force, duress, intimidation, or without legal consent (as with a minor). 2. The performance of such an act. [L. rapio, to seize, to drag away]

rapeseed oil
rapeseed oil (rap′sed)

The compressed oil from the seeds of Brassica campestris (family Cruciferae); used in the manufacture of soaps, margarine, and lubricants. [L. rapa, turnip]

raphania
raphania (ra-fa′ne-a)

A spasmodic disease supposed to be due to poisoning by the seeds of Rhaphanus rhaphanistrum, the wild radish. SYN: rhaphania.

raphe
raphe (ra′fe) [TA]

The line of union of two contiguous, bilaterally symmetrical structures. SYN: rhaphe. [G. rhaphe, suture, seam]
amnionic r. the line of fusion of the amnionic folds over the embryo in reptiles, birds, and certain mammals.
r. anococcygea SYN: anococcygeal ligament.
anogenital r. in the male embryo the line of closure of the genital folds and swellings extending from the anus to the glans of the penis; it is differentiated in the adult into three regions: perineal r., scrotal r., and penile r..
r. corporis callosi a slight anteroposterior furrow on the median line of the upper surface of the corpus callosum.
iliococcygeal r. [TA] portion of anococcygeal body formed by the attachment of the right and left halves of the iliococcygeus (muscle) to each other in the midline, posterior to the anal canal. SYN: r. musculi iliococcygeus [TA] .
lateral palpebral r. a narrow fibrous band in the lateral part of the orbicularis oculi muscle formed by the interlacing of fibers passing through the upper and lower eyelids. SYN: palpebral r., r. palpebralis lateralis.
r. linguae SYN: median sulcus of tongue.
median longitudinal r. of tongue SYN: median sulcus of tongue.
r. of medulla oblongata SYN: r. medullae oblongatae.
r. medullae oblongatae [TA] the seamlike median zone of the medulla oblongata, marked by intercrossing fiber bundles among which lie scattered neuronal cell bodies. SYN: r. of medulla oblongata.
r. musculi iliococcygeus [TA] SYN: iliococcygeal r..
r. palati [TA] SYN: palatine r..
palatine r. [TA] a rather narrow, low elevation in the center of the hard palate that extends from the incisive papilla posteriorly over the entire length of the mucosa of the hard palate. SYN: r. palati [TA] , palatine ridge.
palpebral r. SYN: lateral palpebral r..
r. palpebralis lateralis SYN: lateral palpebral r..
penile r. SYN: r. of penis.
r. penis [TA] SYN: r. of penis.
r. of penis [TA] the continuation of the r. of the scrotum onto the underside of the penis. SYN: r. penis [TA] , penile r..
perineal r. [TA] the central anteroposterior line of the perineum, most marked in the male, being continuous with the r. of the scrotum. SYN: r. perinei [TA] .
r. perinei [TA] SYN: perineal r..
pharyngeal r. [TA] the central line of the pharynx posteriorly where the muscular fibers meet and partly interlace. SYN: r. pharyngis [TA] .
r. pharyngis [TA] SYN: pharyngeal r..
r. of pons SYN: r. pontis.
r. pontis [TA] the continuation of the r. medullae oblongatae into the pars dorsalis (or tegmentum) pontis. SYN: r. of pons.
pterygomandibular r. [TA] a tendinous thickening of the buccopharyngeal fascia, separating and giving origin to the buccinator muscle anteriorly and the superior constrictor of the pharynx posteriorly. SYN: r. pterygomandibularis [TA] , pterygomandibular ligament.
r. pterygomandibularis [TA] SYN: pterygomandibular r..
r. retinae the horizontal line separating the superior and inferior portions of the temporal retina over which the retinal nerve fibers do not course.
scrotal r. SYN: r. of scrotum.
r. scroti [TA] SYN: r. of scrotum.
r. of scrotum [TA] a central line, like a cord, running over the scrotum from the anus to the root of the penis; it marks the position of the septum scroti. SYN: r. scroti [TA] , scrotal r., Vesling line.
Stilling r. the transverse interdigitations of fiber bundles across the anterior median fissure of the medulla oblongata at the decussation of the pyramidal tracts.

Rapoport
Rapoport

Samuel Mitja, Russian biochemist, 1912–1977. See R.-Luebering shunt.

Rapoport
Rapoport

Abraham, Canadian urologist, *1926. See R. test.

Rappaport
Rappaport

Henry, U.S. pathologist, *1913. See R. classification.

rapport
rapport (rap-or′)

1. A feeling of relationship, especially when characterized by emotional affinity. 2. A conscious feeling of harmonious accord, trust, empathy, and mutual responsiveness between two or more persons ( e.g., physician and patient) that fosters the therapeutic process. [Fr.]

rapture of the deep
rapture of the deep (rap′choor)

SYN: nitrogen narcosis (2) .

rarefaction
rarefaction (rar-e-fak′shun)

1. The process of becoming light or less dense; the condition of being light; opposed to condensation. 2. In vascular physiology, the process that results in a reduction in the density of capillaries in a tissue. [L. rarus, thin, scanty + facio, to make]

rarefy
rarefy (rar′e-fi)

To become light or less dense.

RAS
RAS

Abbreviation for reticular activating system.

rasceta
rasceta (ra-se′ta)

The transverse wrinkling on the anterior surface of the wrist. [Mod. L. raseta, fr. Ar. rahah, the palm of the hand]

rash
rash

Lay term for a cutaneous eruption. [O. Fr. rasche, skin eruption, fr. L. rado, pp. rasus, to scratch, scrape]
antitoxin r. a cutaneous manifestation of serum sickness.
black currant r. the cutaneous eruption of lentigines seen in xeroderma pigmentosum.
butterfly r. SYN: butterfly (2) .
caterpillar r. SYN: caterpillar dermatitis.
crystal r. SYN: miliaria crystallina.
diaper r. SYN: diaper dermatitis.
heat r. SYN: miliaria rubra.
hydatid r. a toxic eruption occasionally following the rupture of a hydatid cyst.
Murray Valley r. SYN: epidemic polyarthritis.
serum r. a cutaneous manifestation of serum sickness.
summer r. SYN: miliaria rubra.
wildfire r. SYN: miliaria rubra.

rasion
rasion (ra′zhun)

The subdivision of a crude drug by a rasp to prepare it for extraction. [L. rasio, a scraping, fr. rado, pp. rasus, to scrape, shave]

Rasmussen
Rasmussen

Grant L., American neuroanatomist, *1904. See bundle of R., r. encephalitis, R. syndrome.

Rasmussen
Rasmussen

Fritz W., Danish physician, 1834–1881. See R. aneurysm.

raspatory
raspatory (ras′pa-tor-e)

A surgical instrument used to smooth the edges of a divided bone. [L. raspatorium]

RAST
RAST

Acronym for radioallergosorbent test.

Rastelli
Rastelli

Gian C. See R. operation.

rat
rat

A rodent of the genus Rattus (family Muridae), involved in the spread of some diseases, including bubonic plague.
albino rats rats with white fur and pink eyes; used extensively in laboratory experiments.
Wistar rats an inbred strain of rats, homozygous at most loci, produced by strict brother-sister inbreeding over many generations to develop animals for research with the same general genetic composition. [Wistar Institute]

rate
rate (rat)

1. A record of the measurement of an event or process in terms of its relation to some fixed standard; measurement is expressed as the ratio of one quantity to another ( e.g., velocity, distance per unit time). 2. A measure of the frequency of an event in a defined population; the components of a r. are: the numerator (number of events); the denominator (population at risk of experiencing the event); and the specified time in which the events occur. [L. ratum, a reckoning (see ratio)]
abortion r. 1. the number of induced abortions per 1000 preganancies that resulted in a livebirth, stillbirth, or induced termination. 2. the number of terminations ×1000 ÷ the female population ages 15–44 years.
age-specific r. a r. for a specified age group, in which the numerator and denominator refer to the same age group.
attack r. a cumulative incidence r. used for particular groups observed for limited periods under special circumstances, such as during an epidemic.
average flow r. the flow r. determined by dividing the total volume of urine passed by the time of voiding.
basal metabolic r. (BMR) SYN: basal metabolism.
baseline fetal heart r. the average heart r. for a particular fetus during the diastolic phase of uterine contractions.
birth r. a summary r. based on the number of live births in a population over a given period, usually 1 year; the numerator is the number of live births, the denominator is the midyear population.
case fatality r. the proportion of individuals contracting a disease that die of that disease.
concordance r. the proportion of a random sample of pairs that are concordant for a trait of interest. A high r. of concordance may be generated in several ways, many of which may result from irrelevant bias; but broadly it is taken as evidence of causal connection ( e.g., in the case of identical twins, a genetic component or in spouses of assortative mating).
critical r. a heart r. at which aberration or incomplete block will occur; a result of shortening of cycle length so that it barely includes the refractory period.
death r. an estimate of the proportion of the population that dies during a specified period, usually a year; the numerator is the number of people dying, the denominator is the number in the population, usually an estimate of the number at the midperiod. SYN: crude death r., lethality r., mortality r., mortality (2) .
erythrocyte sedimentation r. (ESR) the r. of settling of red blood cells in anticoagulated blood; increased rates are often associated with anemia or inflammatory states.
fatality r. the death r. observed in a designated series of persons affected by a simultaneous event such as a disaster.
fetal death r. the number of fetal deaths divided by the sum of live births and fetal deaths occurring in the same population during the same time period. SYN: stillbirth r..
fetal heart r. in the fetus, the number of heart beats per minute, normally 120–160.
five-year survival r. the proportion of patients still alive five years after a diagnosis or form of treatment is completed. Usually applied to statistics of survival of cancer patients, since, after five years, recurrences are much less likely to occur.
general fertility r. a refined measure of fertility in a population; the numerator is the number of live births in a year, the denominator is the number of females of child-bearing age, usually defined as ages 15–44 (but increasingly recognized as extending to age 49).
glomerular filtration r. (GFR) the volume of water filtered out of the plasma through glomerular capillary walls into Bowman capsules per unit time; it is considered to be equivalent to inulin clearance.
gross reproduction r. the average number of female children a woman would have if she survived to the end of her childbearing years and if, throughout that period, she were subject to a given set of age-specific fertility rates and a given sex ratio at birth; this r. provides a measure of the replacement fertility of a population in the absence of mortality.
growth r. absolute or relative growth increase, expressed per unit of time.
growth r. of population a measure of population change in the absence of migration, comprising addition of newborns and subtraction of deaths; the result is known as the natural r. of increase of the population; it is the difference between the crude birth r. and the crude death r..
hazard r. theoretical measure of the risk of occurrence of an event, e.g., death, new disease, at a point in time.
heart r. r. of the heart's beat, recorded as the number of beats per minute.
inception r. the r. at which new spells of illness or cases of a condition occur in a population.
incidence r. the r. at which new events occur in a population. The numerator is the number of new events occurring in a defined period; the denominator is the population at risk of experiencing the event during this period.
infant mortality r. a measure of the r. of deaths of liveborn infants before their first birthday; the numerator is the number of infants under one year of age born alive in a defined region during a calendar year who die before they are one year old; the denominator is the total number of live births; often quoted as a useful indicator of the level of health in a community.
initial r. SYN: initial velocity.
lethality r. SYN: death r..
maternal death r. the number of maternal deaths that occur as the direct result of the reproductive process per 100,000 live births. See r.. SEE ALSO: maternal death. SYN: maternal mortality ratio.
mitotic r. the proportion of cells in a tissue that are undergoing mitosis, expressed as a mitotic index or, roughly, as the number of cells in mitosis in each microscopic high-power field in tissue sections.
morbidity r. the proportion of patients with a particular disease during a given year per given unit of population.
mortality r. SYN: death r..
mucociliary clearance r. velocity of movement of the mucus blanket over respiratory epithelium, usually expressed in mm/hour.
mutation r. the probability (or proportion) of progeny genes with a particular component of the genome not present in either biologic parent; usually expressed as the number of mutants per generation occurring at one gene or locus.
neonatal mortality r. the number of deaths in the first 28 days of life divided by the number of live births occurring in the same population during the same period of time.
peak flow r. maximum urinary flow r. during voiding as measured by a uroflowmeter.
perinatal mortality r. the number of stillborn infants of 24 completed weeks or more plus the number of deaths occurring under 28 days of life divided by the number of stillborn infants of 24 weeks or more gestation plus all liveborn infants in the same population, regardless of the period of gestation.
pulse r. r. of the pulse as observed in an artery; recorded as beats per minute.
recurrence r. in genetic counseling, the risk that a future offspring will be affected given some specific set of relatives of whom at least one is already affected.
repetition r. the number of pulses per minute, describing an energy output, e.g., ultrasound pulses in echocardiography rather than vascular pulses.
respiratory r. frequency of breathing, recorded as the number of breaths per minute.
sedimentation r. the r. at which a sediment is deposited from a solution. SEE ALSO: erythrocyte sedimentation r..
shear r. the change in velocity of parallel planes in a flowing fluid separated by unit distance; its units expressed in seconds⁻¹.
slew r. in electronic pacemaker function, the maximum r. of change of an amplifier output voltage; important variable affecting heart function as controlled by an electronic pacemaker. Sensing circuits in the pacemaker often respond to the slew r. rather than to the absolute amplitude of the voltage pulse.
steady-state r. SYN: steady-state velocity.
steroid metabolic clearance r. (MCR) a measure of the r. of metabolism of a given steroid within the body, usually expressed as liters of body fluid that contain the amount of steroid metabolized per day.
steroid production r. the total quantity of a given steroid formed in the body, usually expressed as milligrams per day; represents the sum of the glandular secretion of the steroid and extraglandular formation of it from various steroid precursors.
steroid secretory r. the r. of glandular secretion of a given steroid, usually expressed as milligrams per day; does not include any amount of the steroid that might be formed extraglandularly.
stillbirth r. SYN: fetal death r..
voiding flow r. urinary flow as a function of time during micturition, as graphically recorded by a flow meter.

Rathke
Rathke

Martin H., German anatomist, physiologist, and pathologist, 1793–1860. See R. bundles, under bundle, R. cleft cyst, R. diverticulum, R. pocket, R. pouch, R. pouch tumor.

rating of perceived exertion
rating of perceived exertion

Subjective numerical rating (range 6–19) of exercise intensity based on how an individual feels in relation to level of physiologic stress. An RPE of 13 or 14 (exercise that feels “somewhat hard”) coincides with an exercise heart rate of about 70% maximum.

ratio
ratio (ra′she-o)

An expression of the relation of one quantity to another ( e.g., of a proportion or rate). SEE ALSO: index (2) , quotient. [L. r. (ration-) a reckoning, reason, fr. reor, pp. ratus, to reckon, compute]
absolute terminal innervation r. the number of motor endplates divided by the number of terminal axons related to them.
accommodative convergence-accommodation r. (AC/A) the amount of convergence (measured in prism diopters of convergence) divided by the amount of accommodation (measured in diopters) required to direct both eyes upon an object.
A/G r. abbreviation for albumin-globulin r..
albumin-globulin r. (A/G r.) the r. of albumin to globulin in the serum or in the urine in kidney disease; the normal r. in the serum is approximately 1.55.
ALT:AST r. the r. of serum alanine aminotransferase to serum aspartate aminotransferase; elevated serum levels of both enzymes characterize hepatic disease; when both levels are abnormally elevated and the ALT:AST r. is greater than 1.0, severe hepatic necrosis or alcoholic hepatic disease is likely; when the r. is less than 1.0, an acute nonalcoholic hepatic condition is favored.
amylase-creatinine clearance r. a test for the diagnosis of acute pancreatitis; it is determined by measuring amylase and creatinine in serum and urine; in apparently healthy individuals the renal clearance of amylase is less than 5% that of creatinine; in acute pancreatitis the r. is said to be greater than 5%.
body-weight r. body weight (in grams) divided by stature (in centimeters).
cardiothoracic r. the r. of the horizontal diameter of the heart to the inner diameter of the rib cage at its widest point as determined on a chest roentgenogram.
case fatality r. the mortality rate of a disease, usually expressed per 100 cases.
r. of decayed and filled surfaces (RDFS) an index of decayed and filled permanent surfaces per person, per full complement of 122 tooth surfaces.
r. of decayed and filled teeth (RDFT) an index of decayed and filled permanent teeth per person, per full complement of 28 teeth.
extraction r. (E) the fraction of a substance removed from the blood flowing through the kidney; it is calculated from the formula (A —V)/A, where A and V, respectively, are the concentrations of the substance in arterial and renal venous plasma.
fertility r. a measure of the fertility of a population based on the female population in the child-bearing age group, defined as ages 15–49 years.
flux r. the r. of the two unidirectional fluxes through a particular boundary layer or membrane.
functional terminal innervation r. the number of muscle fibers divided by the number of axons that innervate them.
grid r. in a radiographic scatter-absorbing grid, the r. of the height to the width of the gaps between lead strips; a higher grid r. removes more scattered radiation but requires more careful x-ray tube positioning to avoid grid cutoff of the primary radiation beam.
gyromagnetic r. in nuclear magnetic resonance, the r. of the magnetic dipole moment of the nucleus to the nuclear spin angular momentum; the gyromagnetic r. is a unique value for each type of nucleus. SYN: magnetogyric r..
hand r. the r. of the length of the hand (measured on the dorsum from the styloid process of the ulna to the tip of the third finger) to the width across the knuckles.
international normalized r. (INR) the prothrombin time r. that would have been obtained if a standard reagent had been used in a prothrombin time determination; the prothrombin time r. is expressed as the patient prothrombin time divided by the mean of the prothrombin time reference interval; the prothrombin time r. is obtained for a working reagent in the laboratory through use of a parameter designated the international sensitivity index. SEE ALSO: international sensitivity index.
IRI/G r. the r. of immunoreactive insulin to serum or plasma glucose; in hypoglycemic states a r. of less than 0.3 is usual, with the exception of the hypoglycemia due to insulinoma, where the r. is often higher than 0.3.
K:A r. abbreviation for ketogenic-antiketogenic r..
ketogenic-antiketogenic r. (K:A r.) the proportion between substances that form ketones in the body and those that form d-glucose.
lecithin/sphingomyelin r. (L/S r.) a r. used to determine fetal pulmonary maturity, found by testing the amniotic fluid; when the lungs are mature, lecithin exceeds sphingomyelin by 2 to 1.
L/S r. abbreviation for lecithin/sphingomyelin r..
magnetogyric r. (mag′ne-to-gy-rik) SYN: gyromagnetic r..
mass-action r. the r. of the product of all of the product concentrations divided by the product of all of the reactant concentrations of a particular reaction; when the reaction has been completed ( i.e., t = ∞), then this r. is equal to the equilibrium constant.
maternal mortality r. SYN: maternal death rate.
M:E r. the r. of myeloid to erythroid precursors in bone marrow; normally it varies from 2:1 to 4:1; an increased r. is found in infections, chronic myelogenous leukemia, or erythroid hypoplasia; a decreased r. may mean a depression of leukopoiesis or normoblastic hyperplasia depending on the overall cellularity of the bone marrow.
mendelian r. the r. of progeny with particular phenotypes or genotypes expected in accordance with Mendel law among the offspring of matings specified as to genotype or phenotype.
molecular weight r. (M_r) SYN: molecular weight.
nuclear-cytoplasmic r. r. of volume of nucleus to volume of cytoplasm, fairly constant for a particular cell type and usually increased in malignant neoplasms.
nucleolar-nuclear r. r. of volume of nucleolus to volume of nucleus, usually increased in malignant neoplasms.
P/O r. a measure of oxidative phosphorylation; the r. of phosphate radicals esterified (forming adenosine 5′-triphosphate from adenosine 5′-diphosphate) to atoms of oxygen consumed by mitochondria; normally, the r. is 3 (starting from NADH). SYN: P/O quotient.
respiratory exchange r. the r. of the net output of carbon dioxide to the simultaneous net uptake of oxygen at a given site, both expressed as moles or STPD volumes per unit time; in the steady state, respiratory exchange r. is equal to the respiratory quotient of metabolic processes.
segregation r. in genetics, the proportion of progeny of a particular genotype or phenotype from actual matings of specified genotypes. The test of a mendelian hypothesis is the comparison of the segregation rate with the mendelian rate.
sex r. 1. the r. of male to female progeny at some specified stage of the life cycle, notably at conception (primary), at birth (secondary), or at any stage between birth and death (tertiary); 2. the r. of the numbers of males to females affected by a particular disease or trait.
signal-to-noise r. the relative intensity of a signal to the random variation in signal intensity, or noise; used to evaluate many imaging techniques and electronic systems.
standardized mortality r. the r. of the number of events observed in a population to the number that would be expected if the population had the same distribution as a standard or reference population.
systolic/diastolic r. a calculation from pulsed Doppler ultrasound determinations of blood flow velocities that reflects intrinsic resistance in an arterial blood vessel.
therapeutic r. the r. of the maximally tolerated dose of a drug to the minimal curative or effective dose; LD₅₀ divided by ED₅₀.
variance r. (F) the distribution of the r. of two independent estimates of the same variance from a gaussian distribution based on samples of sizes (n + 1) and (m + 1), respectively. Estimates are usually based on one such sample analyzed in such a way as to make them independent, e.g., analysis of variance, and F may be used to test a null hypothesis that the observed differences among sample means is no greater than could readily be accounted for by chance.
ventilation/perfusion r. (Va/Q) the r. of alveolar ventilation to simultaneous alveolar capillary blood flow in any part of the lung; because both ventilation and perfusion are expressed per unit volume of tissue and per unit time, which cancel, the units become liters of gas per liter of blood.
waist-hip r. r. of the abdominal circumference at the navel to maximum hip and buttocks circumference.
zeta sedimentation r. (ZSR) the r. of the zetacrit to the hematocrit, normally 0.41–0.54 (41–54%); it is a sensitive indicator of the erythrocyte sedimentation rate (ESR) and, unlike the latter, is unaffected by anemia, which tends to elevate the ESR.

rational
rational (rash′un-al)

1. Pertaining to reasoning or to the higher thought processes; based on objective or scientific knowledge, in contrast to empiric (1). 2. Influenced by reasoning rather than by emotion. 3. Having the reasoning faculties; not delirious or comatose. [L. rationalis, fr. ratio, reason]

rationalization
rationalization (ra-shun-al-i-za′shun)

A postulated psychoanalytic defense mechanism through which irrational behavior, motives, or feelings are made to appear reasonable. [L. ratio, reason]

Ratner Ratner

See Kurzrok-R. test.

ratsbane
ratsbane (rats′ban)

SYN: arsenic.

rattlesnake
rattlesnake (rat′l-snak)

A member of the crotalid genera Crotalus and Sistrurus, characterized by possession of cuticular warning rattles at the tip of the tail.

Rattus
Rattus (rat′us)

The rats, a genus of rodents, family Muridae. R. r., the black r., is the species most commonly responsible for transmitting plague to humans by means of the flea, Xenopsylla cheopis; it is smaller and darker than the Norwegian, sewer, or brown rat (R. norvegicus) and has longer ears and tail. See rat.

Rau
Rau, Ravius, Raw

Johann J., Dutch anatomist, 1668–1719. See R. process, processus ravii.

Rauber
Rauber

August A., German anatomist, 1841–1917. See R. layer.

Rauscher
Rauscher

Frank J., 20th century U.S. oncologist. See R. virus.

Rauwolfia
Rauwolfia (row-wool′fe-a, raw-, rah-)

A genus of tropical trees and shrubs (family Apocynaceae). The powdered whole root of R. serpentina contains alkaloids that produce a sedative-antihypertensive-bradycardiac action; approximately 50% of the total activity is due to reserpine. [L. Rauwolf, German botanist, 16th century]

RAV
RAV

Abbreviation for Rous-associated virus.

Ravius
Ravius

See Rau.

ray
ray (ra)

1. A beam of light, heat, or other form of radiation. The rays from radium and other radioactive substances are produced by a spontaneous disintegration of the atom; they are electrically charged particles or electromagnetic waves of extremely short wavelength. 2. A part or branch that extends radially from a structure. [L. radius]
actinic r. a light r. toward and beyond the violet end of the spectrum that acts upon a photographic plate and produces other chemical effects. SYN: chemical r..
alpha r. SYN: alpha particle.
anode rays those originating in a gas discharge tube and moving in a direction opposite to that of cathode rays; made up of positively charged ions. SYN: positive rays.
Becquerel rays obsolete term for radiation given off by uranium and other radioactive substances; these include α, β, and γ rays.
beta r. SYN: beta particle.
cathode rays a stream of electrons emitted from the negative electrode (cathode) in a Crookes tube; their bombardment of the anode or the glass wall of the tube gives rise to x-rays.
chemical r. SYN: actinic r..
cosmic rays high-velocity particles of enormous energies, bombarding earth from outer space; the “primary radiation” consists of protons and more complex atomic nuclei that, on striking the atmosphere, give rise to neutrons, mesons, and other less energetic “secondary radiation.”
direct rays SYN: primary rays (2) .
gamma rays electromagnetic radiation emitted from radioactive substances; they are high-energy x-rays but originate from the nucleus rather than the orbital shell and are not deflected by a magnet.
glass rays those formed by cathode rays striking the wall of an x-r. tube; a special case of indirect rays and soft x-rays. Obsolete.
grenz r. (grents) very soft x-rays, closely allied to the ultraviolet rays in their wavelength ( i.e., relatively long) and in their biologic action upon tissues; they are produced by a specially built vacuum tube with a hot cathode operating from a transformer delivering not more than 8 kw. [Ger. Grenze, borderline, boundary]
H rays a stream of hydrogen nuclei; i.e., protons.
hard rays rays of short wavelength and great penetrability.
incident r. the r. that strikes the surface before reflection.
indirect rays x-rays generated at a surface other than the anode target.
infrared r. infrared.
intermediate rays those between ultraviolet and x-rays. SYN: W rays.
marginal rays in geometric optics, those rays originating from the periphery.
medullary r. the center of the renal lobule, which has the shape of a small, steep pyramid, consisting of straight tubular parts; these may be either ascending or descending limbs of the nephronic loop or collecting tubules. SYN: Ferrein pyramid, pars radiata lobuli corticalis renis, processus ferreini.
Niewenglowski rays radiation emitted from a phosphorescent body after exposure to sunlight.
parallel rays rays parallel to the axis of an optical system.
paraxial rays in geometric optics, those rays focused at the principal point.
positive rays SYN: anode rays.
primary rays 1. cosmic rays in the form in which they first strike the atmosphere; 2. x-rays generated at the focal spot of the tube. SYN: direct rays.
reflected r. a r. of light or other form of radiant energy which is thrown back from a nonpermeable or nonabsorbing surface; the r. which strikes the surface before reflection is the incident r..
roentgen r. SYN: x-r. (1) .
secondary rays x-rays generated when primary x-r.'s impinge upon matter; scattered radiation.
soft rays x-rays of relatively long wavelength and slight penetrability.
supersonic rays rays with a wavelength higher than that perceptible to the human ear, above 20,000 Hz.
ultrasonic rays ultrasonic.
ultraviolet rays ultraviolet.
W rays SYN: intermediate rays.
x-r. x-r..

Rayer
Rayer

Pierre F., French physician, 1793–1867. See R. disease.

rayl
rayl (ral)

Unit of acoustic impedance. 1 r. = 1 kg × m⁻² × sec⁻¹. [Baron Rayleigh (John W. Strutt), Eng. physicist]

Rayleigh
Rayleigh

Lord John William Strutt, British physicist and Nobel laureate, 1842–1919. See R. equation, R. test.

Raynaud
Raynaud

Maurice, French physician, 1834–1881. See R. syndrome, R. disease, R. phenomenon, R. sign.

Rb
Rb

Symbol for rubidium.

R-banding
R-banding

See R-banding stain.

rbc
rbc, RBC

Abbreviation for red blood cell; red blood count.

RBE
RBE

Abbreviation used in radiation protection for relative biologic effectiveness; Cf. quality factor, QF.

RBF
RBF

Abbreviation for renal blood flow. See effective renal blood flow.

R.C.P.
R.C.P.

Abbreviation for Royal College of Physicians (of England).

R.C.P.(E)
R.C.P.(E), R.C.P.(Edin)

1. Abbreviation for Royal College of Physicians (Edinburgh). 2. Symbol for reactivity.

R.C.P.(I)
R.C.P.(I)

Abbreviation for Royal College of Physicians (Ireland).

R.C.P.S.C.
R.C.P.S.C.

Abbreviation for Royal Colleges of Physicians and Surgeons of Canada.

R.C.S.
R.C.S.

Abbreviation for Royal College of Surgeons (England).

R.C.S.(E)
R.C.S.(E), R.C.S.(Edin)

Abbreviation for Royal College of Surgeons (Edinburgh).

R.C.S.(I)
R.C.S.(I)

Abbreviation for Royal College of Surgeons (Ireland).

RCT
RCT

Abbreviation for randomized controlled trial.

R.D.
R.D.

Abbreviation for registered dietician.

RDA
RDA

Abbreviation for recommended daily allowance.

RDFS
RDFS

Abbreviation for ratio of decayed and filled surfaces.

RDFT
RDFT

Abbreviation for ratio of decayed and filled teeth.

R.D.H.
R.D.H.

Abbreviation for Registered Dental Hygienist.

RDPA
RDPA

Abbreviation for right descending pulmonary artery.

R.E.
R.E.

Abbreviation for right eye.

Re
Re

Symbol for rhenium.

re- re-

Prefix meaning again or backward. [L.]

react
react (re-akt′)

To take part in or to undergo a chemical reaction. [Mod. L. reactus]

reactance
reactance (X) (re-ak′tans)

The weakening of an alternating electric current by passage through a coil of wire or a condenser. SYN: inductive resistance.

reactant
reactant (re-ak′tant)

A substance taking part in a chemical reaction.
acute phase reactants a group of proteins that are produced and/or released in increased concentrations during the acute phase reaction, including fibrinogen; C-reactive protein; complement proteins B, C3, C4; α₂-acid glycoprotein, serum amyloid A, proteinase inhibitors, etc.

reaction
reaction (re-ak′shun)

1. The response of a muscle or other living tissue or organism to a stimulus. 2. The color change effected in litmus and certain other organic pigments by contact with substances such as acids or alkalies; also the property that such substances possess of producing this change. 3. In chemistry, the intermolecular action of two or more substances upon each other, whereby these substances are caused to disappear, new ones being formed in their place (chemical r.). 4. In immunology, in vivo or in vitro action of an antibody on a specific antigen, with or without the involvement of a complement or other components of the immunologic system. [L. re-, again, backward, + actio, action]
accelerated r. a response occurring in a shorter time than expected; the cutaneous manifestations occurring during the period between the second and tenth day following smallpox vaccination; because it is intermediate between a primary r. and an immediate r., it is regarded as evidence of some degree of resistance. SYN: vaccinoid r..
acid r. 1. any test by which an acid r. is recognized, such as the change of blue litmus paper to red; 2. an excess of hydrogen ions over hydroxide ions in aqueous solution indicated by a pH value less than 7 (at 22°C). Cf.:dissociation constant of water.
acute phase r. refers to the changes in synthesis of certain proteins within the serum during an inflammatory response; this response provides rapid protection for the host against microorganisms via nonspecific defense mechanisms. SYN: acute phase response.
acute situational r. SYN: stress r..
acute stress r. SYN: anxiety r..
adverse r. any undesirable or unwanted consequence of a preventive, diagnostic, or therapeutic procedure or regimen.
alarm r. the various phenomena, e.g., stimulated endocrine activity, which the body exhibits as an adaptive response to injury or stress; first phase of the general adaptation syndrome.
aldehyde r. the r. of the indole derivatives with aromatic aldehydes; e.g., tryptophan and p-dimethylaminobenzaldehyde in H₂SO₄ give a red-violet color useful in assaying proteins for tryptophan content. SYN: Ehrlich r..
alkaline r. 1. any test by which an alkaline r. is recognized, such as the change of red litmus paper to blue; 2. an excess of hydroxide ions over hydrogen ions in aqueous solution as indicated by a pH value >7 (at 22°C). Cf.:dissociation constant of water. SYN: basic r..
allergic r. a local or general r. of an organism following contact with a specific allergen to which it has been previously exposed and sensitized; immunologic interaction of endogenous or exogenous antigen with antibody or sensitized lymphocytes gives rise to inflammation or tissue damage. Allergic reactions are classified into four major types: type I, anaphylactic and IgE dependent; type II, cytotoxic; type III, immune-complex mediated; type IV, cell mediated (delayed). SYN: hypersensitivity r..
amphoteric r. a double r. possessed by certain fluids that have a combination of acid and alkaline properties.
anamnestic r. augmented production of an antibody due to previous exposure of the subject to the same antigen.
anaphylactic r. (an′a-fi-lak′tik) SYN: anaphylaxis.
anaplerotic r. anaplerotic.
antigen-antibody r. (AAR) the reversible phenomenon, occurring in vitro or in vivo, of an antibody combining with an antigen of the type that stimulated the formation of the antibody, thereby resulting in agglutination, precipitation, complement fixation, greater susceptibility to ingestion and destruction by phagocytes, or neutralization of exotoxin. SEE ALSO: skin test.
anxiety r. a psychologic r. or experience involving the apprehension of danger accompanied by a feeling of dread and such physical symptoms as an increase in the rate of breathing, sweating, and tachycardia, in the absence of a clearly identifiable fear stimulus; when chronic, it is called generalized anxiety disorder. SEE ALSO: panic attack. SYN: acute stress r..
Arias-Stella r. SYN: Arias-Stella phenomenon.
arousal r. change in pattern of the brain waves when the subject is suddenly awakened and becomes alert.
Arthus r. 1. SYN: Arthus phenomenon. 2. Arthus-type r.; r. in humans and other species that results from the same basic immunologic (allergic) mechanism that evokes, in the rabbit, the typical Arthus phenomenon. SEE ALSO: immune complex disease.
Ascoli r. a method for confirming the diagnosis of anthrax by means of a precipitin r., which indicates the presence of heat-stable Bacillus anthracis antigen in the extracted tissue.
associative r. a secondary or side r..
basic r. SYN: alkaline r..
Bence Jones r. the classic means of identifying Bence Jones protein, which precipitates when urine (from patients with this type of proteinuria) is gradually warmed to 45–70°C and redissolves as the urine is heated to near boiling; as the specimen cools, the Bence Jones protein precipitates in the indicated range of temperature and redissolves as the temperature of the specimen becomes less than 30–35°C.
Berthelot r. the r. of ammonia with phenol-hypochlorite to give indophenol; the principle is used to analyze ammonia concentration in body fluids.
bi bi r. a r. catalyzed by a single enzyme in which two substrates and two products are involved; the ping-pong mechanism may be involved in such a r.. Cf.:mechanism.
Bittorf r. in cases of renal colic, pain radiating to the kidney upon squeezing the testicle or pressing the ovary.
biuret r. the formation of biuret that gives a violet color as a result of the r. of a polypeptide of more than three aminoacyl residues with CuSO₄ in strongly alkaline solution; dipeptides and amino acids (except histidine, serine, and threonine) do not so react; used for the detection and quantification of polypeptides, or proteins, in biologic fluids.
Bloch r. SYN: dopa r..
Bordet and Gengou r. See complement fixation.
Brunn r. the increased absorption of water through the skin of the frog when the animal is injected with pituitrin and immersed in water; one of the physiologic reactions used to study and classify posterior pituitary polypeptides and their analogues.
Burchard-Liebermann r. a blue-green color produced by acetic anhydride with cholesterol (and other sterols) dissolved in chloroform, when a few drops of concentrated sulfuric acid are added. See Liebermann-Burchard test.
Cannizzaro r. formation of an acid and an alcohol by the simultaneous oxidation of one aldehyde molecule and reduction of another; a dismutation: 2RCHO → RCOOH + RCH₂OH; when the aldehydes are not identical, this is referred to as a crossed Cannizzaro r..
capsular precipitation r. SYN: quellung r. (2) .
Carr-Price r. the r. of antimony trichloride with vitamin A to yield a brilliant blue color; this r. forms the basis of several quantitative techniques for the determination of vitamin A.
catalatic r. decomposition of H₂O₂ to O₂ and H₂O, as in the action of catalase; analogous to peroxidase r..
catastrophic r. the disorganized behavior that is the response to a severe shock or threatening situation with which the person cannot cope.
cell-mediated r. immunologic r. of the delayed type, involving chiefly T lymphocytes, important in host defense against infection, in autoimmune diseases, and in transplant rejection. SEE ALSO: skin test.
chain r. a self-perpetuating r. in which a product of one step in the r. itself serves to bring about the next step in the r.. Cf.:autocatalysis.
Chantemesse r. a conjunctival r., especially as applied to typhoid.
cholera-red r. a test for cholera vibrio whereby the addition of 3 or 4 drops of sulfuric acid (concentrated, chemically pure) to an 18-hour-old bouillon or peptone culture of the organism produces a color from rose-pink to claret.
chromaffin r. production of a yellow-brown to brown coloration in normal and abnormal cells containing epinephrine and norepinephrine, when fresh tissue slices are placed in a dichromate-chromate mixture overnight; useful for detection of pheochromocytoma (adrenal medulla) and other tumors which produce catecholamines.
circular r. in sensorimotor theory, the tendency of an organism to repeat novel experiences.
cocarde r., cockade r. Römer test.
colloidal gold r. a test (now obsolete) based on precipitation of cerebrospinal fluid protein when mixed with colloidal gold. Abnormalities in this r. were observed in patients with syphilis, multiple sclerosis, poliomyelitis, and encephalitis.
complement-fixation r. complement fixation.
consensual r. contraction of the pupil of the fellow eye in consensus with the pupil of the illuminated eye. SYN: consensual light reflex, indirect pupillary r..
constitutional r. a generalized r. in contrast to a focal or local r.; in allergy the immediate or delayed response, following the introduction of an allergen, occurring at sites remote from that of injection.
conversion r. SYN: conversion hysteria.
cross-r. a specific r. between an antiserum and an antigen complex other than the antigen complex that evoked the various specific antibodies of the antiserum. It is due to at least one antigenic determinant that is included among the determinants of the other complex.
cutaneous graft versus host r. an acute erythematous maculopapular r. with bulla formation in the most severe cases; chronic changes may resemble lichen planus or scleroderma.
cytotoxic r. an immunologic (allergic) r. in which noncytotropic IgG or IgM antibody combines with specific antigen on cell surfaces; the resulting complex initiates the activation of complement which causes cell lysis or other damage, or which, in the absence of complement, may lead to phagocytosis or enhance T lymphocyte involvement leading to cellular cytotoxicity.
Dale r. Schultz-Dale r..
dark r. in photosynthesis, the fixation of CO₂ into carbohydrate, which is independent in place and time of the absorption of light.
decidual r. the cellular and vascular changes occurring in the endometrium at the time of implantation.
delayed r. a local or generalized response that begins 24–48 hours after exposure to an antigen involving T cells. See cell-mediated r.. SYN: contact hypersensitivity (2) , delayed hypersensitivity (2) , late r., tuberculin-type hypersensitivity.
depot r. reddening of the skin at the point where the needle entered, in the subcutaneous tuberculin test.
depressive r. SYN: depression (4) .
dermotuberculin r. SYN: Pirquet test.
diazo r. the r. of diazotized sulfanilic acid with bilirubin to form azobilirubin, which forms the basis of quantitating the amount of bilirubin in biologic fluids. See van den Bergh test. SYN: Ehrlich diazo r..
digitonin r. the r. of naturally occurring steroids with 3β-hydroxyl groups with digitonin, a steroid glycoside, resulting in the formation of an insoluble precipitate; useful in determining the presence of cholesterol and ergosterol.
Dische r. the assay of DNA by means of the blue color formed with diphenylamine in acid (Dische reagent).
dissociative r. r. characterized by such dissociative behavior as amnesia, fugues, sleepwalking, and dream states.
dopa r. a dark staining observed in fresh tissue sections to which a solution of dopa has been applied, presumably due to the presence of dopa oxidase in the protoplasm of certain cells. SYN: Bloch r..
dystonic r. a state of abnormal tension or muscle tone, similar to dystonia, produced as a side effect of certain antipsychotic medication; a severe form, in which the eyes appear to roll up into the head, is called oculogyric crisis.
early r. SYN: immediate r..
echo r. SYN: echolalia.
Ehrlich r. SYN: aldehyde r..
Ehrlich benzaldehyde r. a test for urobilinogen in the urine, by dissolving 2 g of dimethyl-p-aminobenzaldehyde in 100 mL of 5% hydrochloric acid and adding this reagent to urine; a red color in the cold indicates the presence of an excessive amount of urobilinogen.
Ehrlich diazo r. SYN: diazo r..
eosinopenic r. reduction in the numbers of circulating eosinophils by ACTH or by adrenal corticoids.
error-prone polymerase chain r. use of PCR under conditions in which misincorporation of bases is favored, e.g., where random mutants are sought for a portion of amplified DNA.
eye-closure pupil r. a constriction of both pupils when an effort is made to close eyelids forcibly held apart; a variant of the pupil response to near vision. SYN: Galassi pupillary phenomenon, Gifford reflex, lid-closure r., orbicularis phenomenon, orbicularis pupillary reflex, Piltz sign, Westphal pupillary reflex, Westphal-Piltz phenomenon.
false-negative r. an erroneous or mistakenly negative response.
false-positive r. an erroneous or mistakenly positive response.
Fenton r. 1. the use of H₂O₂ and ferrous salts (Fenton reagent) to oxidize α-hydroxy acids to α-keto acids or to convert 1,2-glycols to α-hydroxy aldehydes; 2. the formation of OH&chmpnt;, OH⁻, and Fe³⁺ from the nonenzymatic r. of Fe²⁺ with H₂O₂; a r. of importance in the oxidative stress in blood cells and various tissues.
Fernandez r. a delayed hypersensitivity lepromin r., similar to a tuberculin r., at the site of intradermal injection of Dharmendra antigen in a lepromin test.
ferric chloride r. of epinephrine an intense emerald green color in a neutral or slightly acid solution of epinephrine when ferric chloride is added to it; a r. typical of catechols.
Feulgen r. Feulgen stain.
fight or flight r. the theory advanced by Walter Cannon, that in the autonomic nervous system and the effectors connected with it, the organism in situations of danger requiring either fight or flight is provided with a check-and-drive mechanism that puts it in readiness to meet emergencies with undivided energy output. Also known as the emergency theory.
first-order r. a r. the rate of which is proportional to the concentration of the single substance undergoing change; radioactive decay is a first-order process, defined by the equation dN/dt = kN, where N is the number of atoms subject to decay (r.), t is time, and k is the first-order decay (r.) constant, i.e., the fraction of all atoms decaying per unit of time. SEE ALSO: decay constant, order.
fixation r. complement fixation.
flocculation r. a form of precipitin r. in which precipitation occurs over a narrow range of antigen-antibody ratio, owing chiefly to peculiarities of the antibody (precipitin).
focal r. a r. that occurs at the point of entrance of an infecting organism or of an injection, as in the Arthus phenomenon. SYN: local r..
Folin r. the r. of amino acids in alkaline solution with 1,2-naphthoquinone-4-sulfonate (Folin reagent) to yield a red color; useful for quantitative assay. SYN: Folin reagent.
Forssman r. SYN: Forssman antigen-antibody r..
Forssman antigen-antibody r. the combination of Forssman antibody with heterogenetic antigen of the Forssman type, as in the agglutination of sheep erythrocytes (which contain Forssman antigen) by serum from a person with infectious mononucleosis that contains Forssman antibody. SYN: Forssman r..
fragment r. a r. used to assay the activity of peptidyl transferase.
Frei-Hoffmann r. SYN: Frei test.
fright r. after section and degeneration of the facial nerve of an animal, the denervated facial muscles contract if the animal is frightened or becomes angry; caused by the release of acetylcholine into the circulation.
fuchsinophil r. the property possessed by certain elements, when stained with acid fuchsin, of retaining the stain when treated with picric acid alcohol.
furfurol r. production of a red color on addition of furfurol to a solution of aniline.
galvanic skin r. SYN: galvanic skin response.
gel diffusion reactions SYN: gel diffusion precipitin tests, under test.
Gell and Coombs reactions allergic r..
gemistocytic r. a r. to injury resulting in the proliferation of reactive, protoplastic, or gemistocytic astrocytes.
general adaptation r. general adaptation syndrome.
Gerhardt r. SYN: Gerhardt test for acetoacetic acid.
graft versus host r. (GVHR) clinical and histologic changes of graft versus host disease occurring in a specific organ.
group r. a r. with an agglutinin or other antibody that is common (though usually in varying concentrations) to an entire group of related bacteria, e.g., the coli group.
Gruber r. SYN: Widal r..
Gruber-Widal r. SYN: Widal r..
Günning r. the formation of iodoform from acetone by iodine and ammonia in alcohol.
Haber-Weiss r. the r. of superoxide (O₂&chmpnt;⁻) with hydrogen peroxide to produce molecular oxygen (O₂), hydroxide radical (OH&chmpnt;), and OH⁻; often, iron-catalyzed; a source of oxidative stress in blood cells and various tissues.
harlequin r. sudden blanching of the lower half of the body of an infant lying on its side, leaving the remaining half of the body the normal color.
heel-tap r. heel tap.
hemoclastic r. hemolysis as observed in the laking of the blood.
Henle r. dark brown staining of the medullary cells of the adrenal bodies when treated with the salts of chromium, the cortical cells remaining unstained.
Herxheimer r. an inflammatory r. in syphilitic tissues (skin, mucous membrane, nervous system, or viscera) induced in certain cases by specific treatment with Salvarsan, mercury, or antibiotics; believed to be due to a rapid release of treponemal antigen with an associated allergic r. in the patient. SYN: Jarisch-Herxheimer r..
Hill r. that portion of the photosynthesis r. that involves the photolysis of water and the liberation of oxygen and does not include carbon dioxide fixation. It involves the addition of oxidants (quinones or ferricyanide) to chloroplasts; upon illumination, O₂ is evolved and the added oxidant is reduced.
homograft r. rejection of an allogenic graft by the host.
hunting r. an unusual r. of digital blood vessels exposed to cold; vasoconstriction is alternated with vasodilation in irregular repeated sequences, in an apparent hunting of equilibrium of skin temperature.
hypersensitivity r. SYN: allergic r..
id r. an allergic manifestation of candidiasis, the dermatophytoses, and other mycoses characterized by itching, vesicular lesions that appear in response to superficial infections that are distant from the id r. itself. SEE ALSO: dermatophytid, -id (1) .
r. of identity gel diffusion precipitin tests in two dimensions, under test.
immediate r. local or generalized response that begins within a few minutes to about an hour after exposure to an antigen to which the individual has been sensitized. SEE ALSO: skin test, wheal-and-erythema r.. SYN: early r..
immediate hypersensitivity r. an immune response mediated by antibody, usually IgE, which occurs within minutes after a second encounter with an antigen, resulting in the release of histamine and subsequent swelling and vasodilation.
immune r. antigen-antibody r. indicating a certain degree of resistance, usually in reference to the 36- to 48-hour r. in vaccination against smallpox; because the degree of resistance indicated by the r. is not true immunity and may disappear relatively rapidly there is a tendency to refer to the immune r. as an allergic r..
incompatible blood transfusion r. a syndrome due to intravascular hemolysis of transfused blood by serum antibodies of the recipient, which react with an antigen of the donor red cells; characterized by chills, fever, backache or muscle cramps, hemoglobinemia, hemoglobinuria, and oliguria, which may result in acute renal failure, DIC, and death.
indirect pupillary r. SYN: consensual r..
intracutaneous r., intradermal r. a r. following the injection of antigen into the skin of a sensitive subject, such as in the case of the tuberculin test.
iodate r. of epinephrine a r. dependent upon the oxidation of epinephrine by iodine liberated from iodate, which is decomposed by the hormone; a faint pink color results.
iodine r. of epinephrine a r. resulting from the oxidation of the hormone, a faint pink color appearing upon the addition of iodine.
irreversible r. a r. or response by the tissues to a pathogenic agent characterized by a permanent pathologic change.
Jaffe r. a bright orange-red complex resulting from the treatment of creatinine with alkaline picrate solution; the basis of most routine creatinine tests.
Jarisch-Herxheimer r. SYN: Herxheimer r..
Jolly r. rapid loss of response to faradic stimulation of a muscle with the galvanic response and the power of voluntary contraction retained; an obsolete method for detecting myasthenia gravis. SYN: myasthenic r..
Kiliani-Fischer r. Kiliani-Fischer synthesis.
late r. SYN: delayed r..
lengthening r. in the decerebrate animal, the rather sudden relaxation with lengthening of the extensor muscles when a limb is passively flexed; associated with clasp-knife spasticity.
lepromin r. a delayed hypersensitivity r. at the site of an intradermal injection of a lepromin, such as the Dharmendra antigen or Mitsuda antigen, in a lepromin test; the reactions, such as the Fernandez or Mitsuda r., are variable, occurring in 48 hours or 3–5 weeks, but are uniformly negative in lepromatous leprosy, borderline leprosy, and mid-borderline leprosy.
leukemoid r. leukemoid r..
lid-closure r. SYN: eye-closure pupil r..
Liebermann-Burchard r. Burchard-Liebermann r..
ligase chain r. a technique for target amplification of DNA in which DNA ligase is used to join two complementary oligonucleotide probes that have bound to a target sequence in vitro. The ligation product is used as a template for ligation of complementary oligonucleotides that, through repeated enzymatic processing, allow for logarithmic accumulation of products that can be used to determine the presence of the target of interest.
local r. SYN: focal r..
local anesthetic r. a toxic r. due to absorption of local anesthetic drug during regional anesthesia, ranging from drowsiness to convulsions and cardiovascular collapse.
Loewenthal r. the agglutinative r. in relapsing fever.
Lohmann r. the r. catalyzed by creatine kinase.
magnet r. a r. seen in an animal deprived of its cerebellum; when the animal is placed upon its back and the head strongly flexed, the four limbs become flexed in all their joints. Because of stimulation of receptors in the deep layers of the skin, light pressure made upon a toe-pad with the finger causes reflex contraction of the limb extensors; the limb is thus pressed gently against the finger, and when the finger is withdrawn slightly, the experimenter has the sensation that the finger is raising the limb or drawing it out as by a magnet.
Marchi r. failure of the myelin sheath of a nerve to blacken when submitted to the action of osmic acid.
Mazzotti r. SYN: Mazzotti test.
Millon r. the r. of phenolic compounds ( e.g., tyrosine in protein) with Hg(NO₃)₂ in HNO₃ (and a trace of HNO₂) to give a red color.
miostagmin r. a physiochemical immunity test, designed by Ascoli, consisting in determination of the surface tension of an immune serum to which its specific antigen has been added, before and after incubation at 37°C for 2 hours; in a positive r. the surface tension, as measured by the stalagmometer, is lowered.
Mitsuda r. a delayed hypersensitivity lepromin r., in the form of erythematous papular nodules, at the site of intradermal injection of Mitsuda antigen in a lepromin test.
mixed agglutination r. immune agglutination in which the aggregates contain cells of two different kinds but with common antigenic determinants; when used to identify isoantigens, the test cells are exposed to appropriate isoantibody, washed, and then mixed with indicator erythrocytes that combine with free sites on the test cell-attached isoantibody.
mixed lymphocyte culture r. mixed lymphocyte culture test.
monomolecular r. a r. involving a single molecule ( e.g., decomposition, intramolecular rearrangement, intramolecular oxidation or reduction), even if a catalytic agent, such as acid or alkali, is present in large excess, on a molecular basis, or is not rate-determining; such reactions are usually first-order reactions. Cf.:molecularity. SYN: unimolecular r..
myasthenic r. SYN: Jolly r..
Nadi r. SYN: peroxidase r..
near r. the pupillary constriction associated with a near vision effort, i.e., with accommodation and convergence.
nested polymerase chain r. use of the PCR in series such that a specified piece of DNA is amplified, then a portion contained within the first piece is amplified further; used where extremely low amounts of DNA are present, or where there are problems with background or contaminating DNA.
Neufeld r. SYN: Neufeld capsular swelling.
neurotonic r. muscular contraction continuing well after cessation of stimulation.
neutral r. pH of 7.00; H⁺ and OH⁻ ion concentrations equal at 10⁻⁷ mol/L at 22°C. Cf.:dissociation constant of water.
ninhydrin r. a test for proteins, peptones, peptides, and amino acids possessing free carboxyl and α-amino groups that is based upon the r. with triketohydrinene hydrate; a blue color r. is used to quantitate free amino acids ( e.g., after hydrolysis and separation of the amino acids of a protein). SYN: triketohydrindene r..
nitritoid r. a severe r. resembling that following the administration of nitrites, sometimes following intravenous administration of arsphenamine or other drugs; consists of flushing of the face, edema of the tongue and lips, vomiting, profuse sweating, a fall in blood pressure, and sometimes death.
r. of nonidentity gel diffusion precipitin tests in two dimensions, under test.
nuclear r. the interaction of two atomic nuclei or of one such with a subatomic particle, or of the subatomic particles within an atomic nucleus, resulting in a change in the nature of the nuclei concerned or in the energy content of the nuclei or both, usually manifested by transmutation (accompanied by emission of alpha-, beta-, and/or gamma-rays) or by fission or fusion of the nuclei.
oxidase r. 1. the formation of indol blue when a blood smear containing myeloid leukocytes is treated with a mixture of α-naphthol and p-dimethylaniline sulfate; the myeloid leukocytes contain an oxidase that catalyzes this r., and the lymphoid leukocytes do not; 2. in bacteriology, a r. that depends on the presence of certain oxidases in some bacteria that catalyze the transport of electrons between electron donors in the bacteria and an oxidation reduction dye, such as tetramethyl-p-phenylenediamine; the dye is reduced to a blue or black color.
oxidation-reduction r. oxidation-reduction.
pain r. dilation of the pupil or any other involuntary act occurring in response to a stimulus causing sharp pain anywhere.
Pandy r. a test to determine the presence of proteins (chiefly globulins) in the spinal fluid, by adding one drop of spinal fluid to 1 mL of solution ( e.g., carbolic acid crystals in distilled water, cresol, or pyrogallic acid); the r. varies from a faint turbidity to a dense “milky” precipitate according to the degree of protein content. SYN: Pandy test.
r. of partial identity gel diffusion precipitin tests in two dimensions, under test.
passive cutaneous anaphylactic r. passive cutaneous anaphylaxis.
Paul r. pus is rubbed into a scarification on a rabbit's eye; if the pus is from a variolous or vaccinal pustule a condition of epitheliosis develops in 36–48 hours; the sputum of a smallpox patient is said to cause the same r.. SYN: Paul test.
performic acid r. oxidative destruction of the ethylene double bond (–HC&dbond;CH–) which is converted to a Schiff-reactive double aldehyde; used to indicate the presence of unsaturated lipids, such as phospholipids and cerebrosides, as well as cystine-rich substances, such as keratin, in tissue sections.
periosteal r. radiographically detectable new subperiosteal bone formed as a r. to soft tissue or osseous disease.
peroxidase r. formation of indophenol blue by the action of an oxidizing enzyme present in certain cells and tissues when they are treated with a solution of α-naphthol and dimethylparaphenylenediamine; by this method, cells of the myelocyte series, which give a positive r., may be distinguished from those of the lymphocyte series, which give a negative r.. SYN: Nadi r..
phosphoroclastic r. cleavage of C–C bonds that involves phosphate transfer but not, as in phosphorolysis, directly to one of the products; e.g., the decomposition of pyruvate to acetate + CO₂, in which orthophosphate is added to ADP to form ATP.
Pirquet r. SYN: Pirquet test.
plasmal r. a histochemical technique that uses mercuric chloride to unmask the aldehyde group of acetalphosphatides and permit Schiff staining.
pleural r. thickening of the pleural stripe on chest radiographs, representing pleuritis, pleural effusion, or pleural fibrosis.
polymerase chain r. (PCR) (po-lim′er-as) an enzymatic method for the repeated copying of the two strands of DNA of a particular gene sequence. It is widely used to amplify minute quantities of biological material so as to provide adequate specimens for laboratory study.The replication of DNA in the living cell is facilitated by polymerases. The two DNA chains of the double helix first unzip from one another, and DNA polymerase then generates a copy of each strand by adding free nucleotides to form a sequence of base pairs complementary with the sequence in the strand. The laboratory technique known as polymerase chain r., for which the American biochemist Kary Mullis won a Nobel Prize in Chemistry in 1993, exploits the capacity of DNA polymerase to assemble new DNA. Taq polymerase, named for its source, Thermus aquaticus, a thermophilic bacterium, is added to a mixture of free nucleotides and primers. (Primers are specially prepared units containing both RNA and DNA with a free terminus where the polymerase will react.) The short sequence of DNA to be amplified is flanked by two primers. Once the r. begins, the polymerase generates numerous copies of the target sequence. The sequential phases of the r. are initiated simply by making a series of strategic changes in the temperature of the system. Millions of copies of the target sequence can be generated by cyclically repeating these temperature changes as many as 30 times, each DNA strand produced by one cycle giving rise to many more in the next. The technique is used to amplify specimens for diagnosis of both infectious and genetic diseases, to carry out DNA fingerprinting, and in genomic research.
Porter-Silber r. the basis of the 17-hydroxycorticosteroid test; C-21 adrenocorticosteroids, which contain a dihydroxyacetone group at carbons 19, 20, and 21, react with phenylhydrazine.
Prausnitz-Küstner r. a test for the presence of immediate hypersensitivity in humans; test serum from an atopic individual is injected intradermally into a normal subject; the normal subject is challenged 24–48 hours later with the antigen suspected of causing the immediate hypersensitivity r. in the atopic individual, usually in the form of a wheal flare. SYN: P-K test.
precipitin r. See precipitin, precipitin test.
primary r. SYN: vaccinia.
prozone r. prozone.
psychogalvanic r., psychogalvanic skin r. SYN: galvanic skin response.
quellung r. 1. SYN: Neufeld capsular swelling. 2. if pneumococcal organisms, India ink, and specific antisera are mixed, the antibodies present in the sera will bind to the polysaccharide antigens of the pneumococcal capsule and the capsule will appear more opaque and swollen. This test will identify the organism as being pneumococci as well as the specific capsular types. SYN: capsular precipitation r.. [Ger. Quellung, swelling]
reversed Prausnitz-Küstner r. the appearance of an urticarial r. at the site of injection when serum containing reaginic antibody is injected into the skin of a person in whom the allergen is already present.
reverse transcriptase polymerase chain r. (RT-PCR) a process for specific mRNA amplification wherein reverse transcriptase added to the in vitro r. uses mRNA as a template to produce one cDNA, which is then amplified by the usual PCR.
reversible r. a chemical r. that takes place in either direction, i.e., from the forward or reverse direction; ionization is such a r., as are reactions involving racemases, isomerases, mutases, transferases, etc.
Sakaguchi r. guanidines in alkaline solution develop an intense red color when treated with α-naphthol and sodium hypochlorite; a qualitative test for arginine, free or in a protein.
Schardinger r. the reduction of methylene blue to methylene white by formaldehyde is rapidly catalyzed by fresh milk but not by boiled milk, the catalyzing agent being xanthine oxidase (Schardinger enzyme); an example of oxidation in the absence of O₂ with an organic hydrogen acceptor (the dye).
Schultz r. Schultz stain.
Schultz-Charlton r. the specific blanching of a scarlatinal rash at the site of intracutaneous injection of scarlatina antiserum. SYN: Schultz-Charlton phenomenon.
Schultz-Dale r. the contraction of an excised intestinal loop (Schultz) or of an excised strip of virginal uterus (Dale) from a sensitized animal (guinea pig) that occurs when the tissue is exposed to the specific antigen.
serum r. SYN: serum sickness.
shortening r. the adaptive shortening of the extensor muscles of the limb of a decerebrate animal when the limb is extended after it has been flexed. Cf.:lengthening r..
Shwartzman r. SYN: Shwartzman phenomenon.
skin r. SYN: skin test.
specific r. the phenomena produced by an agent that is identical with or immunologically related to the one that has already caused an alteration in capacity of the tissue to react.
startle r. SYN: startle reflex.
Straus r. a diagnostic test for glanders. Male guinea pigs are inoculated intraperitoneally with suspected material; if the glanders organism is present, it will usually set up a necrotizing inflammation in the scrotal sac within a few days and the specific organism can be confirmed bacteriologically.
stress r. an acute emotional r. related to extreme environmental threat or challenge. SYN: acute situational r..
supporting reactions described by Magnus, who distinguished two types: positive supporting reactions, consisting of those reflex muscular contractions whereby the body is supported against gravity; seen in an exaggerated form in the decerebrate animal; negative supporting reactions, consisting of inhibition of the extensor muscles and unfixing of the joints that thus enable the limb to be flexed and moved into a new position. SYN: supporting reflexes.
symptomatic r. an allergic response similar to the original one, but occurring after the use of a test or therapeutic dose of an allergen or atopen.
thermoprecipitin r. the throwing down of a precipitate on the application of heat, as in the case of proteinaceous urine.
transcription-based chain r. a technique for target amplification of DNA or RNA in which reverse transcriptase is used to produce a single-stranded DNA molecule for each DNA or RNA target; this molecule is used as a template for further amplification.
Treponema pallidum immobilization r. SYN: Treponema pallidum immobilization test.
triketohydrindene r. SYN: ninhydrin r..
type III hypersensitivity r. SYN: immune complex disease.
unimolecular r. SYN: monomolecular r..
vaccinoid r. SYN: accelerated r..
Voges-Proskauer r. a chemical r. used in testing for the production of acetyl methyl carbinol by various bacteria; potassium hydroxide is added to a 24-hour culture in a suitable medium and thoroughly mixed; the treated culture is exposed to air and is observed at intervals of 2, 12, and 24 hours; a positive r. consists of the development of an eosin-like pink color, due to the production of acetylmethylcarbinol, which in the presence of alkali and oxygen is oxidized to diacetyl.
Wassermann r. (W.r.) SYN: Wassermann test.
Weidel r. a r. showing the presence of xanthine; a solution of the suspected substance in chlorine water with a little nitric acid is evaporated in a water bath, and then exposed to the vapor of ammonia; the presence of xanthine is indicated when a red or purple color develops.
Weil-Felix r. SYN: Weil-Felix test.
Weinberg r. a complement fixation test of the presence of hydatid disease.
Wernicke r. in hemianopia, a r. due to damage of the optic tract, consisting in loss of pupillary constriction when the light is directed to the blind side of the retina; pupillary constriction is maintained when light stimulates the normal side. This sign cannot be seen with a bright light because of intraocular scatter onto the seeing half of the retina. SYN: Wernicke sign.
wheal-and-erythema r. the characteristic immediate r. observed in the skin test; within 10–15 minutes after injection of antigen (allergen), an irregular, blanched, elevated wheal appears, surrounded by an area of erythema (flare). SYN: wheal-and-flare r..
wheal-and-flare r. SYN: wheal-and-erythema r..
white r. the response seen in many individuals after the skin is lightly stroked with a blunt instrument; it is attributed to capillary action.
whitegraft r. an immune r. to a incompatible tissue graft that results in failure of graft vascularization and ensuing rejection.
Widal r. agglutination r. as applied to the diagnosis of typhoid. SYN: Gruber r., Gruber-Widal r..
xanthoprotein r. a qualitative test for proteins; a yellow product is formed by reacting proteins with hot, concentrated nitric acid.
Yorke autolytic r. a test for paroxysmal hemoglobinuria; serum is placed in an ice chest and kept at 0°C for 5–7 minutes, then in an incubator at 37°C with erythrocytes for 1 hour, at which time, if the r. is positive, hemolysis occurs; if the serum is kept at 1°C for an hour and then placed in the incubator with erythrocytes there is little hemolysis.
zero-order r. a r. that proceeds at a particular rate independently of the concentration of the reactant or reactants.
Zimmermann r. a chemical r. between an alkaline solution of meta-dinitrobenzene and an active methylene group (carbon-16) of 17-ketosteroids; it is the basis of the 17-ketogenic steroid assay test; more generally, a r. between methylene ketones and aromatic polynitro compounds in alkaline solutions. SYN: Zimmermann test.

reactivate
reactivate (re-ak′ti-vat)

1. To render active again. 2. In particular, of an inactivated immune serum to which normal serum (complement) is added.

reactivation
reactivation (re′ak-ti-va′shun)

1. Restoration of the lytic activity of an inactivated serum by means of the addition of complement. 2. Restoration of activity in an inactivated enzyme.

reactivity
reactivity (re-ak-tiv′i-te)

1. The property of reacting, chemically or in any other sense. 2. The process of reacting.

reading
reading (red′ing)

1. The perception and understanding of the meaning of visual symbols ( e.g., letters or words) by the scanning of writing or print with the eyes. 2. Any of several alternative ways of interpreting symbols, such as Braille or the close observation of a speaker's facial movements.
lip r. SYN: speech r..
speech r. used by people with hearing impairment of nonauditory clues as to what is being said through observing the speaker's facial expressions, lip and jaw movements, and other gestures. SYN: lip r..

reading frame
reading frame

The grouping of nucleotides by threes into codons. See frame-shift mutation.
blocked r. a sequence of DNA that cannot be translated into a viable protein; usually due to the interruption by one or more termination codons. SYN: closed r..
closed r. SYN: blocked r..
open r. a gene presumed to code for a protein but for which no gene product has been identified; also known as unidentified r.. SYN: unidentified r..
unidentified r. (URF) SYN: open r..

readthrough
readthrough (red′throo)

In molecular biology, transcription of a nucleic acid sequence beyond its normal termination sequence.

reagent
reagent (re-a′jent)

Any substance added to a solution of another substance to participate in a chemical reaction. [Mod. L. reagens]
amino acid r. a r. used in the identification and quantification of amino acids.
Benedict-Hopkins-Cole r. magnesium glyoxalate, made from a mixture of oxalic acid and magnesium, used for testing proteins for the presence of tryptophan.
biuret r. an alkaline solution of copper sulfate.
Cleland r. SYN: dithiothreitol.
diazo r. two solutions, one of sodium nitrite, the other of acidified sulfanilic acid, used in bringing about diazotization. SYN: Ehrlich diazo r..
Dische r. Dische reaction.
Dische-Schwarz r. r. used in the colorimetric detection of RNA.
Drabkin r. a solution used in the cyanmethemoglobin method of measuring hemoglobin. It consists of sodium bicarbonate, potassium cyanide, and potassium ferricyanide.
Dragendorff r. a r. used in the detection of alkaloids.
Edlefsen r. an alkaline permanganate solution used in the determination of sugar in the urine.
Edman r. SYN: phenylisothiocyanate.
Ehrlich diazo r. SYN: diazo r..
Erdmann r. a mixture of sulfuric and nitric acids, used in testing alkaloids.
Esbach r. picric acid, citric acid, and water (in the proportions 1, 2, and 97) used for the detection of albumin in the urine.
Exton r. 50 g of sulfosalicylic acid and 200 g of Na₂SO₄&chmpnt;10H₂O in a liter of water, used as a test for albumin.
Fehling r. SYN: Fehling solution.
Folin r. SYN: Folin reaction.
Fouchet r. a 25% solution of trichloroacetic acid, containing 0.9% ferric chloride; a drop of the r. added at the surface line of barium chloride-impregnated filter paper that has been dipped in urine for 10 s will give a green color if bilirubin is present. SEE ALSO: Fouchet stain.
Froehde r. sodium molybdate in strong sulfuric acid; this r. gives various color reactions with alkaloids.
Frohn r. bismuth subnitrate (1.5) and water (20.0) heated to boiling, to which hydrochloric acid (10.0) and potassium iodide (7.0) are added; used to test for alkaloids and for sugar.
Girard r. the hydrazine of betaine chloride, used to extract ketonic steroids by forming water-soluble hydrazones with them.
Günzberg r. phloroglucin and vanillin used as a r. in Günzberg test.
Hahn oxine r. an alcoholic solution of 8-hydroxyquinoline used in the determination of zinc, aluminum, magnesium, and other minerals.
Hammarsten r. a mixture of 1 part 25% solution of nitric acid and 19 parts 25% solution of hydrochloric acid; the addition of a few drops to a mixture of 1 part of this r. and 4 parts alcohol will give a green color if bile is present.
Ilosvay r. sulfanilic acid 0.5, dissolved in dilute acetic acid 150, mixed with naphthylamine 1, and dissolved in boiling water 20; the blue sediment that forms is dissolved in dilute acetic acid 150; a few drops of this r. added to water, saliva, or other fluid to be tested will produce a red color if nitrites are present.
Kasten fluorescent Schiff reagents fluorescent analogs of Schiff r. that are fluorescent basic dyes lacking acidic side groups and containing one or more primary amine groups; used in cytochemical detection of DNA in Kasten fluorescent Feulgen stain, polysaccharides in Kasten fluorescent PAS stain, and proteins in the ninhydrin-Schiff stain; such analogs include acriflavine, auramine O, and flavophosphine N.
Lloyd r. precipitated aluminum silicate, used in the determination of alkaloids.
Mandelin r. a solution of ammonium vanadate in sulfuric acid, used in color tests for alkaloids.
Marme r. a solution of potassium iodide and cadmium iodide used in testing for alkaloids.
Marquis r. a solution of formaldehyde in sulfuric acid used in color tests for formaldehyde.
Mecke r. a solution of selenous acid in sulfuric acid, used for color tests of alkaloids.
Meyer r. a solution of phenolphthalein with sodium hydroxide, in water (glass-distilled); in the presence of minute traces of blood, the solution becomes purple or blue-red.
Millon r. mercuric nitrate and nitric acid as used in the Millon reaction.
Nessler r. a solution of potassium hydroxide, mercuric iodide, and potassium iodide; it yields a yellow color with ammonia (a brown precipitate with larger amounts) that can be used for quantitative assay.
Rosenthaler-Turk r. a solution of potassium arsenate in sulfuric acid used in obtaining color tests for various opium alkaloids.
Sanger r. SYN: fluoro-2,4-dinitrobenzene.
Schaer r. an alcoholic or aqueous solution of chloral hydrate used as an extraction medium in investigations of alkaloids.
Scheibler r. a solution of sodium tungstate in phosphoric acid used in tests for alkaloids.
Schiff r. an aqueous solution of basic fuchsin or pararosaniline that is decolorized by sulfur dioxide, commonly prepared by addition of hydrochloric acid to a dye solution containing a metabisulphite or bisulphite salt; used for aldehydes and in histochemistry to detect polysaccharides, DNA, and proteins. See Feulgen stain, periodic acid-Schiff stain, ninhydrin-Schiff stain for proteins.
Scott-Wilson r. an alkaline solution of mercuric cyanide and silver nitrate used in the detection of acetone.
sulfhydryl r. r. that reacts with thiol groups, particularly those in proteins.
Sulkowitch r. a r. for the detection of calcium in the urine, consisting of 2.5 g of oxalic acid, 2.5 g of ammonium oxalate, 5 mL of glacial acetic acid, and distilled water to make 150 mL; a milky precipitate of calcium oxalate is formed when the r. is added to urine that contains calcium.
Uffelmann r. a solution prepared by adding a 2% solution of phenol in water to aqueous ferric chloride until the solution becomes violet in color; this turns lemon yellow in the presence of lactic acid, assumes an opaline tint in butyric acid, and is decolorized by hydrochloric acid.
Wurster r. filter paper impregnated with tetramethyl-p-phenylenediamine, which turns blue in the presence of ozone or hydrogen peroxide.

reagin
reagin (re-a′jin)

1. Wolff-Eisner term for antibody. 2. Old term for the “Wassermann” antibody; not to be confused with the Prausnitz-Küstner antibody. 3. Antibodies that mediate immediate hypersensitivity reactions (IgE in humans). 4. SYN: homocytotropic antibody.
atopic r. SYN: Prausnitz-Küstner antibody.

reaginic
reaginic (re-a-jin′ik)

Pertaining to a reagin.

REAL
REAL

Abbreviation for Revised European-American Classification of Lymphoid Neoplasms. See R. classification .

reality
reality (re-al′i-te)

That which exists objectively and in fact, and can be consensually validated. [L. res, thing, fact]

reality awareness
reality awareness

The ability to distinguish external objects as being different from oneself.

reamer
reamer (re′mer)

A rotating finishing or drilling tool used to shape or enlarge a hole in bone or a tooth. [A.S. ryman, to widen]
engine r. an engine-mounted spirally bladed instrument, used for enlarging the root canals of teeth.
intramedullary r. a rasp used for shaping the intramedullary canal of a large bone before inserting an appliance or prosthesis.

rearrangement
rearrangement (re-a-ranj-ment)

A restructuring; E.G., in a molecule.
Amadori r. a r. that occurs in cross-linking reactions seen in collagen and in protein glycosylations; E.G., conversion of N-glycosides of aldoses to N-glycosides of the corresponding ketoses.

reassignment
reassignment

sex r. a process whereby the sex of an individual is changed by a combination of psychiatric, psychologic, pharmacologic, and surgical procedures, usually as a part of the treatment of hermaphroditism transexualism. SYN: sex reversal.

reattachment
reattachment (re-a-tach′ment)

New epithelial or connective tissue attachment to the surface of a tooth that was surgically detached and not exposed to oral environment.

Réaumur
Réaumur

René A.F. de, French physicist, 1683–1757. See R. scale.

rebase
rebase (re′bas)

In dentistry, to refit a denture by replacing the denture base material without changing the occlusal relationship of the teeth. SEE ALSO: reline.

rebreathing
rebreathing (re-bredh′ing)

Inhalation of part or all of gases previously exhaled.

Rebuck skin window technique
Rebuck skin window technique

See under technique.

RecA
RecA

An Escherichia coli protein that specifically recognizes single-stranded DNA and anneals it to a complementary sequence in a duplex that is homologous. This results in the displacement of the original complementary strand of the duplex.

recalcification
recalcification (re-kal′si-fi-ka′shun)

Restoration to the tissues of lost calcium salts.

recall
recall (re′kawl)

The process of remembering thoughts, words, and actions of a past event in an attempt to recapture actual happenings.

Récamier
Récamier

Joseph C.A., French gynecologist, 1774–1852. See R. operation.

recanalization
recanalization (re-kan′al-i-za′shun)

1. Restoration of a lumen in a blood vessel following thrombotic occlusion, by organization of the thrombus with formation of new channels. 2. Spontaneous restoration of the continuity of the lumen of any occluded duct or tube, as with postvasectomy r..

recapitulation
recapitulation (re′ka-pit′u-la′shun)

See r. theory.

receiver
receiver (re-se′ver)

In chemistry, a vessel attached to a condenser to receive the product of distillation. [L. receptor, fr. recipio, to receive]

receptaculum
receptaculum, pl .receptacula (re′sep-tak′u-lum, -la)

A receptacle. SYN: reservoir. [L. fr. re-cipio, pp. -ceptus, to receive, fr. capio, to take]
r. chyli SYN: cisterna chyli.
r. ganglii petrosi SYN: petrosal fossula.
r. pecqueti SYN: cisterna chyli.

receptive
receptive (re-sep′-tv)

Sensitive or responsive to stimulus.
r. field that part of the retina of which the photoreceptors (rods and cones) pertain to a single optic nerve fiber. The response of a neuron to stimulation of its r. field depends on the type of neuron and the part of the field that is illuminated; an “on-center” neuron is stimulated by light falling at the center of its r. field and inhibited by light falling at the periphery; an “off-center” neuron reacts in exactly the opposite fashion; that is, it is inhibited by light falling at the center of its r. field. In either case, the net response depends on a complex switching action in the retina. When an entire r. field is equally illuminated, the response of receptors at the center of the field predominates.

receptor
receptor (re-sep′tor, tor)

1. A structural protein molecule on the cell surface or within the cytoplasm that binds to a specific factor, such as a drug, hormone, antigen, or neurotransmitter. 2. C. Sherrington term for any one of the various sensory nerve endings in the skin, deep tissues, viscera, and special sense organs. [L. receiver, fr. recipio, to receive]
adrenergic receptors reactive components of effector tissues, most of which are innervated by adrenergic postganglionic fibers of the sympathetic nervous system. Such receptors can be activated by norepinephrine and/or epinephrine and by various adrenergic drugs; r. activation results in a change in effector tissue function, such as contraction of arteriolar muscles or relaxation of bronchial muscles; adrenergic receptors are divided into α-receptors and β-receptors, on the basis of their response to various adrenergic activating and blocking agents. SYN: adrenoceptor, adrenoreceptors.
α-adrenergic receptors adrenergic receptors in effector tissues capable of selective activation and blockade by drugs; conceptually derived from the ability of certain agents, such as phenoxybenzamine, to block only some adrenergic receptors and of other agents, such as methoxamine, to activate only the same adrenergic receptors. Such receptors are designated as α-receptors. Their activation results in physiologic responses such as increased peripheral vascular resistance, mydriasis, and contraction of pilomotor muscles.
β-adrenergic receptors adrenergic receptors in effector tissues capable of selective activation and blockade by drugs; conceptually derived from the ability of certain agents, such as propranolol, to block only some adrenergic receptors and of other agents, such as isoproterenol, to activate only the same adrenergic receptors. Such receptors are designated as β-receptors. Their activation results in physiologic responses such as increases in cardiac rate and force of contraction (β₁), and relaxation of bronchial and vascular smooth muscle (β₂) contained in skeletal muscle.
AMPA r. a type of glutamate r. that participates in excitatory neurotransmission and also binds α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid and acts as a cation channel. SYN: quisqualate r..
angiotensin r. cell-surface G-protein–coupled receptors that mediate the effects of angiotensin II. Two types are recognized: AT₁ and AT₂; the former mediates the powerful vascular smooth-muscle contraction responsible for the hypertensive response produced by angiotensin II; the latter is not sufficiently understood to be assigned any physiologic function.
ANP receptors cell surface receptors for atrial natriuretic peptide that have a single transmembrane spanning element; these have integral kinase and guanylate cyclase domains.
ANP clearance receptors cell surface proteins that bind atrial natriuretic peptide and ANP fragments without initiating biologic action.
asialoglycoprotein r. a surface r. found in hepatocytes that binds galactose-terminal glycoproteins; thus, this r. removes those proteins from circulation and they are in turn acted upon by hepatocyte lysosomes.
B cell receptors a complex comprising a membrane-bound immunoglobulin molecule and two associated signal-transducing α and β chains.
cholinergic receptors chemical sites in effector cells or at synapses through which acetylcholine exerts its action.
epidermal growth factor r. (EGFR) r. often upregulated in epithelial tumors.
estrogen r. r. for estrogens; its presence conveys a better prognosis for breast cancers.
Fas r. See Fas.
Fc r. receptors present on a variety of cells for the Fc fragment of immunoglobulins. These receptors recognize immunoglobulins of the IgG and IgE class.
kainate r. a type of glutamate r. that participates in excitatory neurotransmission and also binds kainate and acts as a cation channel; injection of kainate causes death of neurons but preserves glial cells and axons.
laminin r. a r. found in many cell types that binds laminin and has a role in cell attachment and neurite outgrowth.
L-AP₄ r. a type of glutamate r. that also binds a particular synthetic agonist and acts as a cation channel.
low-density lipoprotein receptors receptors on the surface of cells, especially liver cells, which bind to low-density lipoprotein and promote clearance of LDL from the plasma.
mannose-6-phosphate receptors (MPR) receptors in Golgi apparatus to which newly synthesized proteins that are destined to enter lysosomes bind.
metabotropic r. a type of r. that is linked to intracellular production of 1,2-diacylglycerol and inositol 1,4,5-trisphosphate. [metabolism + G. trope, turning, inclination, + -ic]
muscarinic receptors membrane-bound proteins whose extracellular domain contains a recognition site for acetylcholine (ACh); combination of Ach with the r. initiates a physiologic change (slowing of heart rate, increased glandular secretory activity, and stimulation of smooth muscle contractions); changes are observed after treatment with the mushroom alkaloid muscarine. Muscarinic receptors are to be distinguished from nicotinic receptors.
nicotinic receptors a class of cholinergic receptors on skeletal muscle cells that are linked to ion channels in the cell membrane.
nicotinic cholinergic r. a class of receptors responsive to acetylcholine that also are activated by nicotine; ganglionic (including the adrenal medulla) and neuromuscular receptors. Two classes exist: nicotinic-neuronal and nicotinic-muscular.
NMDA r. a type of glutamate r. that participates in excitatory neurotransmission and also binds N-methyl-d-aspartate; may be particularly involved in the cell damage observed in individuals with Huntington disease.
opiate receptors regions of the brain that have the capacity to bind morphine; some, along the aqueduct of Sylvius and in the center median, are in areas related to pain, but others, as in the striatum, are not related.
orphan r. a nuclear r. for which no ligand has yet been identified.
progesterone r. intracellular r. for progesterone; often over-expressed in breast cancer.
quisqualate r. SYN: AMPA r..
retinoic acid r. nuclear r. for retinoic acid.
retinoid X r. r. for retinoic acids; has less affinity for retinoic acid than the retinoic acid receptors; function is not yet well understood.
ryanodine r. r. associated with a calcium conductance channel in the sacroplasmic or endoplasmic reticulum of cells, which when bound to ryanodine, causes the channel to remain in a subconductive state, allowing slow continuing release of calcium ions from the sarcoplasmic reticulum into the cytoplasm. The channels are normally sensitive to calcium ions and not sensitive to inositol triphosphate.
scavenger r. a r. on macrophages that binds preferentially to oxidized LDL, causing macrophages to internalize the LDL.
sensory receptors peripheral endings of afferent neurons.
stretch receptors receptors that are sensitive to elongation, especially those in Golgi tendon organs and muscle spindles, but also those found in visceral organs such as the stomach, small intestine, and urinary bladder; these receptors have the function of detecting elongation, and this distinguishes them from baroreceptors, which actually are activated by stretching of the wall of the blood vessel but whose function is to elicit central reflex mechanism reducing the arterial blood pressure.
T cell antigen receptors receptors present on T cells that interact with both processed antigen and major histocompatibility antigens simultaneously; these are heterodimers, each consisting of either an α and β chain or a γ and δ chain.

receptosomes
receptosomes (re-sep′to-soms)

Vesicles that avoid lysosomes and deliver their contents to other intracellular sites.

recess
recess (re′ses) [TA]

A small hollow or indentation. SYN: recessus [TA] . [L. recessus]
anterior r. a circumscript deepening of the interpeduncular fossa in the direction of the mamillary bodies. SYN: recessus anterior [TA] .
anterior r. of tympanic membrane [TA] a slitlike space on the tympanic wall between the anterior malleolar fold and the tympanic membrane. SYN: recessus anterior membranae tympanicae [TA] , Tröltsch pockets, Tröltsch recesses.
azygoesophageal r. the region below the azygos vein arch in which the right lung intrudes into the mediastinum between the heart and vertebral column, bordered on the left by the esophagus.
cecal r. SYN: retrocecal r..
cerebellopontine r. cerebellopontine angle.
cochlear r. [TA] a small depression on the inner wall of the vestibule of the labyrinth at the portion of the pyramid of vestibule, between the two limbs into which the vestibular crest divides posteriorly; it is perforated by foramina giving passage to fibers that the cochlear branch of the vestibulocochlear nerve sends to the posterior extremity of the cochlear duct. SYN: recessus cochlearis [TA] , Reichert cochlear r..
costodiaphragmatic r. [TA] the cleftlike extension of the pleural cavity between the diaphragm and the rib cage; pleural effusions collect here when in the upright position, and since the lung only partially enters, this is the site of thoracocentesis. SYN: recessus costodiaphragmaticus [TA] , phrenicocostal sinus.
costomediastinal r. [TA] the r. of the pleural cavity between the costal cartilages and the mediastinum. SYN: recessus costomediastinalis [TA] , costomediastinal sinus.
duodenojejunal r. SYN: superior duodenal fossa.
elliptical r. of bony labyrinth [TA] an oval depression in the roof and inner wall of the vestibule of the labyrinth, lodging the utriculus. SYN: recessus ellipticus labyrinthi ossei [TA] , recessus utricularis labyrinthi ossei&star, utricular r. of bony labyrinth&star, fovea elliptica, fovea hemielliptica.
epitympanic r. [TA] the upper portion of the tympanic cavity above the tympanic membrane; it contains the head of the malleus and the body of the incus. SYN: recessus epitympanicus [TA] , attic, epitympanic space, epitympanum, Hyrtl epitympanic r., tympanic attic.
hepatoenteric r. a peritoneal r. at the caudal end of the embryonic pneumatoenteric r.; it separates the developing liver and stomach.
hepatorenal r. of subhepatic space [TA] the deep r. of the subhepatic space of the peritoneal cavity on the right side extending upward between the liver in front and the kidney and suprarenal behind; this is a gravity-dependent portion of the peritoneal cavity when in the supine position; fluids draining from the omental bursa drain here. SYN: recessus hepatorenalis recessus subhepatici [TA] , hepatorenal pouch, Morison pouch.
Hyrtl epitympanic r. SYN: epitympanic r..
inferior duodenal r. SYN: inferior duodenal fossa.
inferior ileocecal r. [TA] a deep fossa sometimes found between the ileocecal fold, the mesoappendix, and the cecum. SYN: recessus ileocecalis inferior [TA] .
inferior omental r. SYN: inferior r. of omental bursa.
inferior r. of omental bursa [TA] a r. of the omental bursa extending between anterior and posterior layers of the great omentum. SYN: recessus inferior omentalis [TA] , inferior omental r..
infundibular r. [TA] a funnel-shaped diverticulum leading from the anterior portion of the third ventricle down into the infundibulum of the hypophysis. SYN: aditus ad infundibulum [TA] , recessus infundibuli [TA] .
intersigmoid r. [TA] a triangular peritoneal r. posterior and inferior to the sigmoid colon created by the attachment of the sigmoid mesocolon ascending across the left psoas, then turning sharply to descend into the pelvis; the left ureter descends the posterior wall of this r.. SYN: recessus intersigmoideus [TA] .
Jacquemet r. a pouch of peritoneum between the gallbladder and the liver.
lateral r. of fourth ventricle [TA] the narrow r. of the ventricle that extends laterally over, and down along the side of, the inferior cerebellar peduncle and the overlying cochlear nuclei; at its tip it opens by way of Luschka foramen into the interopeduncular cistern of the subarachnoid space. By way of this r., part of the choroid plexus of the fourth ventricle protrudes into the subarachnoid space. SYN: recessus lateralis ventriculi quarti [TA] .
mesentericoparietal r. SYN: parajejunal fossa.
optic r. See supraoptic r..
pancreaticoenteric r. a r. of the embryonic peritoneal cavity that develops into the adult omental bursa.
paracolic recesses SYN: paracolic gutters, under gutter.
paraduodenal r. [TA] an occasional r. in the peritoneum to the left of the terminal portion of the duodenum located posterior to a fold containing the inferior mesenteric vein. SYN: recessus paraduodenalis [TA] , fossa venosa, paraduodenal fossa.
parotid r. SYN: parotid space.
pharyngeal r. [TA] a slitlike depression in the lateral membranous (nonmuscular) pharyngeal wall extending posterior to the opening of the pharyngotympanic (auditory) tube. SYN: recessus pharyngeus [TA] , recessus infundibuliformis, Rosenmüller fossa, Rosenmüller r..
phrenicomediastinal r. [TA] the r. of the pleural cavity between the diaphragm and the mediastinum. SYN: recessus phrenicomediastinalis [TA] .
pineal r. [TA] a diverticulum from the posterior part of the third ventricle extending back between the posterior commissure and the habenular commissure; sometimes extending into the stalk of the pineal. SYN: recessus pinealis [TA] .
piriform r. piriform fossa.
pleural recesses [TA] four recesses of the pleural cavity, one behind the sternum and costal cartilages (costomediastinal r.), one between the diaphragm and chest wall (costodiaphragmatic r.), one between the diaphragm and mediastinum (phrenicomediastinal r.), and one between the vertebral bodies and mediastinum (vertebromediastinal r.). SYN: recessus pleurales [TA] , pleural sinuses.
pneumatoenteric r., pneumoenteric r. a r. of the embryonic celom between the right lung bud and the gut; it is normally largely obliterated before birth, leaving only the superior r. of the vestibule of the lesser peritoneal sac as a vestige.
pontocerebellar r. SYN: cerebellopontine angle.
posterior r. [TA] a deepening of the interpeduncular fossa toward the pons. SYN: recessus posterior [TA] .
posterior r. of tympanic membrane [TA] a narrow pocket in the tympanic wall between the posterior malleolar fold and the tympanic membrane. SYN: recessus posterior membranae tympanicae [TA] , Tröltsch pockets, Tröltsch recesses.
Reichert cochlear r. SYN: cochlear r..
retrocecal r. [TA] one of several small pockets sometimes found extending alongside the right margin of the ascending colon near the cecum. SYN: recessus retrocecalis [TA] , cecal r..
retroduodenal r. [TA] a peritoneal r. occasionally found behind the third part of the duodenum, between it and the aorta. SYN: recessus retroduodenalis [TA] , infraduodenal fossa, retroduodenal fossa.
Rosenmüller r. SYN: pharyngeal r..
sacciform r. of distal radioulnar joint [TA] an extension of the cavity of the distal radioulnar articulation proximad between the two bones; SYN: recessus sacciformis articulationis radioulnaris distalis [TA] .
sacciform r. of elbow joint [TA] an extension of the capsule of the elbow joint at the neck of the radius. SYN: recessus sacciformis articulationis [TA] .
saccular r. of bony labyrinth spherical r. of bony labyrinth.
sphenoethmoidal r. [TA] a small cleftlike pocket of the nasal cavity above the superior concha into which the sphenoid sinuses drain. SYN: recessus sphenoethmoidalis [TA] .
spherical r. of bony labyrinth [TA] a rounded depression on the inner wall of the vestibule of the labyrinth, lodging the sacculus. SYN: recessus saccularis larbyrinthi ossei&star, saccular r. of bony labyrinth&star, fovea hemispherica, fovea spherica, recessus sphericus labyrinthi ossei.
splenic r. [TA] the extension of the omental bursa toward the hilum of the spleen. SYN: recessus splenicus [TA] , recessus lienalis&star.
subhepatic r. SYN: subhepatic space.
subphrenic recesses SYN: subphrenic space.
subpopliteal r. [TA] the extension of the cavity of the knee joint between the tendon of the popliteus and lateral condyle of the femur. SYN: recessus subpopliteus [TA] , bursa of popliteus.
superior azygoesophageal r. the region above the azygos vein arch in which the right lung is in contact with the esophagus.
superior duodenal r. superior duodenal fossa.
superior ileocecal r. [TA] a shallow pouch occasionally existing between the terminal ileum, the cecum, and the ileocolic artery when the latter is present. SYN: recessus ileocecalis superior [TA] .
superior r. of lesser peritoneal sac pneumatoenteric r..
superior omental r. SYN: superior r. of omental bursa.
superior r. of omental bursa [TA] a portion of the vestibule of the bursa omentalis that extends upward between the inferior vena cava and the esophagus. SYN: recessus superior bursae omentalis [TA] , superior omental r..
superior r. of tympanic membrane [TA] a space in the mucous membrane on the inner surface of the tympanic membrane between the flaccid part of the membrane and the neck of the malleus. SYN: recessus superior membranae tympanicae [TA] , Prussak pouch, Prussak space.
supraoptic r. a diverticulum extending forward from the anterior part of the third ventricle above the optic chiasm. SYN: recessus supraopticus [TA] , recessus supraopticus [TA] .
suprapineal r. [TA] a variable diverticulum from the posterior portion of the third ventricle of the brain, running backward some distance above and beyond the pineal r.. SYN: recessus suprapinealis [TA] .
supratonsillar r. SYN: supratonsillar fossa.
triangular r. an occasional evagination of the anterior wall of the third ventricle of the brain between the anterior commissure and the diverging pillars of the fornix. SYN: recessus triangularis.
Tröltsch recesses SYN: anterior r. of tympanic membrane, posterior r. of tympanic membrane.
tubotympanic r. the dorsal portion of the embryonic first endodermal pharyngeal pouch; it develops into the middle ear cavity.
recesses of tympanic cavity [TA] spaces of the tympanic wall around the tympanic membrane. SYN: recessus membranae tympanicae [TA] .
utricular r. of bony labyrinth elliptical r. of bony labyrinth.
utricular r. of membranous labyrinth [TA] part of the utricle that forms a blind-ended pouch that extends into the ellipsoid (utricular) r. of the bony labyrinth. SYN: recessus utricularis labyrinthi membranacei [TA] .
vertebromediastinal r. [TA] pleural r. formed by the reflection of the mediastinal part of the parietal pleura onto the vertebral bodies. SYN: recessus vertebromediastinalis [TA] .

recession
recession (re-sesh′un)

A withdrawal or retreating. SEE ALSO: retraction. [L. recessio (see recessus)]
angle r. tearing of the iris root between the longitudinal and circular ciliary muscles; often leading to glaucoma.
clitoral r. operative procedure to reduce the visual prominence of the clitoris that often occurs in females with congenital adrenal hyperplasia; distinct from clitoral amputation (clitorectomy) or clitoral reduction. SEE ALSO: clitoroplasty.
gingival r. apical migration of the gingiva along the tooth surface, with exposure of the tooth surface. SYN: gingival atrophy, gingival resorption.
tendon r. surgical displacement of the tendon of an eye muscle posterior to its anatomic insertion. SYN: curb tenotomy.

recessitivity
recessitivity (re′ses-i-tiv′i-te)

The state of being recessive (2).

recessive
recessive (re-ses′iv)

1. Drawing away; receding. 2. In genetics, denoting a trait due to a particular allele or alleles at a single locus that does not manifest itself unless mutant alleles are present on both homologous chromosomes of a pair.

recessus
recessus, pl .recessus (re-ses′sus) [TA]

SYN: recess. [L. a withdrawing, a receding]
r. anterior [TA] SYN: anterior recess.
r. anterior membranae tympanicae [TA] SYN: anterior recess of tympanic membrane.
r. cochlearis [TA] SYN: cochlear recess.
r. costodiaphragmaticus [TA] SYN: costodiaphragmatic recess.
r. costomediastinalis [TA] SYN: costomediastinal recess.
r. duodenalis inferior [TA] SYN: inferior duodenal fossa.
r. duodenalis superior [TA] SYN: superior duodenal fossa.
r. ellipticus labyrinthi ossei [TA] SYN: elliptical recess of bony labyrinth.
r. epitympanicus [TA] SYN: epitympanic recess.
r. hepatorenalis r. subhepatici [TA] SYN: hepatorenal recess of subhepatic space.
r. ileocecalis inferior [TA] SYN: inferior ileocecal recess.
r. ileocecalis superior [TA] SYN: superior ileocecal recess.
r. inferior omentalis [TA] SYN: inferior recess of omental bursa.
r. infundibuli [TA] SYN: infundibular recess.
r. infundibuliformis SYN: pharyngeal recess.
r. intersigmoideus [TA] SYN: intersigmoid recess.
r. lateralis ventriculi quarti [TA] SYN: lateral recess of fourth ventricle.
r. lienalis splenic recess.
r. membranae tympanicae [TA] SYN: recesses of tympanic cavity, under recess.
r. paraduodenalis [TA] SYN: paraduodenal recess.
r. parotideus SYN: parotid space.
r. pharyngeus [TA] SYN: pharyngeal recess.
r. phrenicomediastinalis [TA] SYN: phrenicomediastinal recess.
r. pinealis [TA] SYN: pineal recess.
r. piriformis [TA] SYN: piriform fossa.
r. pleurales [TA] SYN: pleural recesses, under recess.
r. posterior [TA] SYN: posterior recess.
r. posterior membranae tympanicae [TA] SYN: posterior recess of tympanic membrane.
r. retrocecalis [TA] SYN: retrocecal recess.
r. retroduodenalis [TA] SYN: retroduodenal recess.
r. sacciformis articulationis [TA] SYN: sacciform recess of elbow joint.
r. sacciformis articulationis radioulnaris distalis [TA] SYN: sacciform recess of distal radioulnar joint.
r. saccularis larbyrinthi ossei spherical recess of bony labyrinth.
r. sphenoethmoidalis [TA] SYN: sphenoethmoidal recess.
r. sphericus labyrinthi ossei SYN: spherical recess of bony labyrinth.
r. splenicus [TA] SYN: splenic recess.
r. subhepaticus [TA] SYN: subhepatic space.
r. subphrenicus [TA] SYN: subphrenic space.
r. subpopliteus [TA] SYN: subpopliteal recess.
r. superior bursae omentalis [TA] SYN: superior recess of omental bursa.
r. superior membranae tympanicae [TA] SYN: superior recess of tympanic membrane.
r. supraopticus [TA] SYN: supraoptic recess.
r. supraopticus [TA] SYN: supraoptic recess.
r. suprapinealis [TA] SYN: suprapineal recess.
r. triangularis SYN: triangular recess.
r. utricularis labyrinthi membranacei [TA] SYN: utricular recess of membranous labyrinth.
r. utricularis labyrinthi ossei elliptical recess of bony labyrinth.
r. vertebromediastinalis [TA] SYN: vertebromediastinal recess.

recidivation
recidivation (re-sid-i-va′shun)

Relapse of a disease, a symptom, or a behavioral pattern such as an illegal activity for which one was previously imprisoned. [L. recidivus, falling back, recurring, fr. re- cido, to fall back]

recidivism
recidivism (re-sid′i-vizm)

The tendency of an individual toward recidivation. [L. recidivus, recurring]

recidivist
recidivist (re-sid′i-vist)

A person who tends toward recidivation.

recipe
recipe (℞) (res′i-pe)

1. The superscription of a prescription, usually indicated by the sign ℞. 2. A prescription or formula. [L. imperative recipio, to receive]

recipient
recipient (re-sip′e-ent)

One who receives, as in blood transfusion or tissue or organ transplant. [L. recipiens, fr. recipio, to receive]

recipiomotor
recipiomotor (re-sip′e-o-mo′ter)

Relating to the reception of motor stimuli. [L. recipio, to receive, + motor, mover]

reciprocation
reciprocation (re-sip-ro-ka′shun)

In prosthodontics, the means by which one part of an appliance is made to counter the effect created by another part. [L. reciprocare, pp. reciprocatus, to move back and forth]

recirculation
recirculation (re-ser-ku-la′shun)

Circular movement of the mucus blanket in a paranasal sinus due to the presence of an accessory ostium or failure to include the natural ostium in sinusotomy.

Recklinghausen
Recklinghausen

Friedrich D. von, German histologist and pathologist, 1833–1910. See R. disease of bone, von R. disease.

reclination
reclination (rek-li-na′shun)

Turning the cataractous lens over into the vitreous to displace it from the line of vision; distinguished from couching, in which the lens is simply depressed into the vitreous. [L. reclino, pp. -atus, to bend back]

recollection
recollection (re-ko-lek′shun)

In renal physiology, a technique in which a known fluid is infused into a renal tubule lumen at one point and collected for analysis by a second micropipette further downstream. [re- + L. collectus, pp. of colligo, to collect]

recombinant
recombinant (re-kom′bi-nant)

1. A cell or organism that has received genes from different parental strains. 2. Pertaining to or denoting such organisms. 3. In linkage analysis, the change of coupling phase at two loci during meiosis. If two syntenic, nonallelic genes are inherited from the same parent, they must be in coupling. An offspring that inherits only one of them is r. and indicates an odd number of cross-overs between the loci; an offspring that inherits neither or both is nonrecombinant and may indicate an even number of cross-overs or none.

recombination
recombination (re-kom-bi-na′shun)

1. The process of reuniting of parts that had become separated. 2. The reversal of coupling phase in meiosis as gauged by the resulting phenotype. SEE ALSO: recombinant. 3. The formation of new combinations of genes.
genetic r. 1. the presence in progeny of combinations of genotypes and perhaps phenotypes, not present in either parent, resulting from crossing-over; 2. in microbial genetics, the inclusion of a chromosomal part or extrachromosomal element of one microbial strain in the chromosome of another; the interchange of chromosomal parts or genes between different microbial strains.
homologous r. the exchange of corresponding stretches of DNA between two sister chromosomes.
site-specific r. integration of foreign DNA into a particular site in the host genome.

recon
recon (re′kon)

Obsolete term for the smallest unit (corresponding to a single DNA nucleotide) of recombination or crossing-over between two homologous chromosomes.

reconstitution
reconstitution (re′kon-sti-too′shun)

1. The restitution or return to an original state of a substance, or combination of parts to make a whole. 2. In the case of a lower organism, the restoration of a part of the body by regeneration.

reconstruction
reconstruction (re-con-struk′shun)

The computerized synthesis of one or more two-dimensional images from a series of x-ray projections in computed tomography, or from a large number of measurements in magnetic resonance imaging; several methods are used; the earliest was back-projection, and the most common is 2D Fourier transformation.
ossicular r. generic term denoting a number of surgical techniques to restore the continuity of the ossicular chain from the tympanic membrane to the oval window for sound pressure transmission and, thereby, improved hearing.

record
record (rek′erd)

1. In medicine, a chronologic written account that includes a patient's initial complaint(s) and medical history, physical findings, results of diagnostic tests and procedures, any therapeutic medicines and/or procedures, and subsequent developments during the course of the illness. 2. In dentistry, a registration of desired jaw relations in a plastic material or on a device to permit these relationships to be transferred to an articulator. [M.E. recorden, fr. O.Fr. recorder, fr. L. recordor, to remember, fr. re-, back, again, + cor, heart]
anesthesia r. a written or electronic account of drugs administered, procedures undertaken, and physiologic responses during the course of surgical or obstetric anesthesia.
face-bow r. a registration utilizing a face-bow of the position of the hinge axis and/or the condyles; the face-bow r. is used to orient the maxillary cast to the opening and closing axis of the articulator.
functional chew-in r. a r. of the natural chewing movements of the mandible made on an occlusion rim by teeth or scribing studs.
hospital r. the medical r. generated during a period of hospitalization, usually including written accounts of consultants' opinions, physicians' and nurses' observations, treatments, and the results of all tests and/or procedures performed.
interocclusal r. a r. of the positional relationship of the teeth or jaws to each other, recorded by placing a plastic material that hardens (such as plaster of Paris or wax) between the occlusal surfaces of the rims or teeth; the hardened material serves as the r.; it may be registered in centric or eccentric positions, as centric interocclusal r., a r. of centric jaw relation; eccentric interocclusal r., a r. of jaw position in other than centric relation; lateral interocclusal r., a r. of a lateral eccentric jaw position; and protrusive interocclusal r., a r. of a protruded eccentric jaw position. SYN: checkbite.
maxillomandibular r. 1. a r. of the relation of the mandible to the maxillae; 2. the act of recording the relation of the mandible to the maxillae. SYN: biscuit bite, maxillomandibular registration.
medical r. r. (1) .
occluding centric relation r. a registration of centric relation made at the established occlusal vertical dimension.
preextraction r. SYN: preoperative r..
preoperative r. in dentistry, any r. made for the purpose of study or treatment planning. SEE ALSO: diagnostic cast. SYN: preextraction r..
problem-oriented r. (POR) a system of r. keeping in which a list of the patient's problems is made and all history, physical findings, laboratory data, etc. pertinent to each problem are placed under that heading; especially useful for outpatient records of patients with multiple problems who are followed for long periods.
profile r. a registration or r. of the profile of a patient.
protrusive r. a registration of a forward position of the mandible with reference to the maxillae.
terminal jaw relation r. a r. of the relationship of the mandible to the maxillae made at the vertical relation of occlusion and at the centric position.
three-dimensional r. a maxillomandibular r. made at the occluding relation.

recording
recording (re-kord′ing)

Preserving the results of a study.
clinical r. SYN: charting.
depth r. study of subcortical cerebral electrical activity after placing electrodes in these areas.

recovery
recovery (re-kov′er-e)

1. A getting back or regaining; recuperation. 2. Emergence from general anesthesia. 3. In nuclear magnetic resonance, refers to relaxation. [M.E., fr. O.Fr. recoverer, fr. L. recupero, to recover, get back, fr. re-, again, + capio, to take]
creep r. the time-dependent portion of the decrease in strain in a material or object following removal of the stress that has deformed it.
inversion r. a magnetic resonance pulse sequence in which a series of 180° magnetic field inversions is followed by a spin echo sequence for signal detection; of note, during r., the longitudinal magnetization vector passes through zero.
short TI inversion r. (STIR) an inversion r. sequence that uses a short inversion time, about 100 ms, between 180° pulses; by proper selection of TI, the signal from water or fat can be suppressed.
spontaneous r. the return of the conditioned response, after apparent extinction, in the presence of the conditioned stimulus without the unconditioned stimulus also being present. See classical conditioning.
ultrasonic egg r. obtaining an egg for in vitro fertilization by means of an ultrasonically guided needle aspiration of ovarian follicles; may be performed transvesically or via the cul-de-sac.

recovery room
recovery room

A hospital facility with special equipment and personnel for the immediate postoperative care of patients as they recover from anesthesia and/or surgery.

recrudescence
recrudescence (re-kroo-des′ens)

Resumption of a morbid process or its symptoms after a period of remission. [L. re-crudesco, to become raw again, break out afresh, fr. crudus, raw, harsh]

recrudescent
recrudescent (re-kroo-des′ent)

Becoming active again, relating to a recrudescence.

recruitment
recruitment (re-kroot′ment)

1. In the testing of hearing, the abnormally greater increase in loudness in response to increments in intensity of the acoustic stimulus in an ear with a sensory hearing loss compared with a normal ear. 2. In neurophysiology, the activation of additional neurons (spatial r.) or an increase in their firing rate (temporal r.). SYN: recruiting response. SEE ALSO: irradiation. 3. The adding of parallel channels of flow in any system. [Fr. recrutement, fr. L. re-cresco, pp. -cretus, to grow again]

rect- rect-

See recto-.

rectal
rectal (rek′tal)

Relating to the rectum.

rectalgia
rectalgia (rek-tal′je-a)

SYN: proctalgia.

rectectomy
rectectomy (rek-tek′to-me)

SYN: proctectomy.

rectifier
rectifier (rek′ti-fi-er)

An electronic device for converting alternating to direct voltage, part of the circuit of an x-ray machine. [Mediev. L. rectifico, to make right, fr. rectus, right + facio to make]

rectify
rectify (rek′ti-fi)

1. To correct. 2. To purify or refine by distillation; usually implies repeated distillations. [L. rectus, right, straight]

rectitis
rectitis (rek-ti′tis)

SYN: proctitis.

recto- recto-, rect-

The rectum. SEE ALSO: procto-. [L. rectum, fr. rectus, straight]

rectoabdominal
rectoabdominal (rek′to-ab-dom′i-nal)

Relating to the rectum and the abdomen; denoting a bimanual method of examination with one hand on the abdominal wall and a finger of the other hand in the rectum.

rectocele
rectocele (rek′to-sel)

SYN: proctocele. [recto- + G. kele, tumor, hernia]

rectoclysis
rectoclysis (rek-tok′li-sis)

SYN: proctoclysis.

rectococcygeal
rectococcygeal (rek-to-kok-sij′e-al)

Relating to the rectum and the coccyx.

rectococcypexy
rectococcypexy (rek-to-kok′si-pek-se)

SYN: proctococcypexy.

rectocolitis
rectocolitis (rek′to-ko-li′tis)

SYN: coloproctitis.

rectoperineal
rectoperineal (rek′to-per-i-ne′al)

Relating to the rectum and perineum.

rectoperineorrhaphy
rectoperineorrhaphy (rek′to-per-i-ne-or′a-fe)

SYN: proctoperineoplasty. [recto- + perineo- + G. rhaphe, a sewing]

rectopexy
rectopexy (rek′to-pek-se)

SYN: proctopexy.

rectophobia
rectophobia (rek-to-fo′be-a)

SYN: proctophobia. [recto- + G. phobos, fear]

rectoplasty
rectoplasty (rek′to-plas-te)

SYN: proctoplasty.

rectorrhaphy
rectorrhaphy (rek-tor′a-fe)

SYN: proctorrhaphy.

rectoscope
rectoscope (rek′to-skop)

SYN: proctoscope.

rectoscopy
rectoscopy (rek-tos′ko-pe)

SYN: proctoscopy.

rectosigmoid
rectosigmoid (rek′to-sig′moyd)

The rectum and sigmoid colon considered as a unit; the term is also applied to the junction of the sigmoid colon and rectum.

rectostenosis
rectostenosis (rek′to-ste-no′sis)

SYN: proctostenosis.

rectostomy
rectostomy (rek-tos′to-me)

SYN: proctostomy.

rectotome
rectotome (rek′to-tom)

SYN: proctotome.

rectotomy
rectotomy (rek-tot′o-me)

SYN: proctotomy.

rectourethral
rectourethral (rek-to-u-re′thral)

Relating to the rectum and the urethra.

rectouterine
rectouterine (rek-to-u′ter-in)

Relating to the rectum and the uterus.

rectovaginal
rectovaginal (rek-to-vaj′i-nal)

Relating to the rectum and the vagina.

rectovesical
rectovesical (rek-to-ves′i-kal)

Relating to the rectum and the bladder.

rectovestibular
rectovestibular (rek′to-ves-tib′u-lar)

Relating to the rectum and the vestibule of the vagina.

rectum
rectum, pl .rectumsrecta (rek′tum, rek′ta)

The terminal portion of the digestive tube, extending from the rectosigmoid junction to the anal canal. (Perineal flexure). [L. rectus, straight, pp. of rego, to make straight]

recumbent
recumbent (re-kum′bent)

Leaning; reclining; lying down. [L. recumbo, to lie back, recline, fr. re-, back, + cubo, to lie]

recuperate
recuperate (re-koo′per-at)

To undergo recuperation. [L. recupero (or recip-), pp. -atus, to take again, recover]

recuperation
recuperation (re-koo-per-a′shun)

Recovery of or restoration to the normal state of health and function. [L. recuperatio (see recuperate)]

recurrence
recurrence (re-kur′ens)

1. A return of the symptoms, occurring as a phenomenon in the natural history of the disease, as seen in recurrent fever. 2. SYN: relapse. 3. Appearance of a genetic trait in a genetic relative of a proband. [L. re-curro, to run back, recur]

recurrent
recurrent (re-kur′ent)

1. In anatomy, turning back on itself. 2. Denoting symptoms or lesions reappearing after an intermission or remission.

recurvation
recurvation (re-ker-va′shun)

A backward bending or flexure. [L. re-curvus, bent back]

red
red

One of the primary colors, occupying the lower extremity of the spectrum at the other end from violet. For individual r. dyes, see specific name. [A.S. reád]

Red Cross
Red Cross

A red Geneva cross on a white background, an international sign to identify medical and other personnel caring for the sick and wounded and facilities devoted to their care in times of war, also the emblem of the American R..

redia
redia, pl .rediae (re′de-a, -de-e)

Intramolluscan development stage of a digenetic trematode, following the primary sporocyst stage, which forms after penetration of the snail tissues by the miracidium. Rediae are produced from cells within the sporocyst, are liberated from the latter, and develop in the tissues of the host snail as elongated, saclike, muscular organisms with a mouth and gut. The rediae may produce one or a number of additional generations in the snail, but they ultimately produce the final development stage, the cercaria. SEE ALSO: sporocyst (1) , miracidium. [F. Redi, Italian physician, 1626–1697]

redifferentiation
redifferentiation (re-dif′er-en′she-a′shun)

The return to a fully specialized condition for the performance of a particular function after a period of nonspecific activity.

redintegration
redintegration (re′din-te-gra′shun)

1. The restoration of lost or injured parts. 2. Restoration to health. 3. The recalling of a whole experience on the basis only of some item or portion of the original stimulus or circumstances of the experience. [L. red-integro, pp. -atus, to make whole again, renew, fr. integer, untouched, entire]

Redlich
Redlich

Emil, Austrian neurologist, 1866–1930. See Obersteiner-R. line, Obersteiner-R. zone.

redox
redox (red′oks)

Contraction of oxidation-reduction. See oxidation-reduction potential.

redressement forcé
redressement forcé (re-dres-mon′ for-sa′)

Obsolete term for straightening by force of a deformed part, as of knock-knee. [Fr.]

redressment
redressment (re-dres′ment)

1. Obsolete term for correction of a deformity; putting a part straight. 2. A renewed dressing of a wound.

reduce
reduce (re-doos′)

1. To place back into a preferred position; to perform reduction (1). 2. In chemistry, to initiate reduction (2). [L. re-duco, to lead back, restore, r.]

reducible
reducible (re-doos′i-bl)

Capable of being reduced.

reductant
reductant (re-duk′tant)

The substance that is oxidized in the course of reduction.

reductase
reductase (re-duk′tas)

An enzyme that catalyzes a reduction; since all enzymes catalyze reactions in either direction, any r. can, under the proper conditions, behave as an oxidase and vice versa, hence the term oxidoreductase. For individual reductases, see the specific names. SYN: reducing enzyme.

reductic acid
reductic acid (re-duk′tik)

A strong reducing product (antioxidant) formed in hot alkaline sugar solutions.

reduction
reduction (re-duk′shun)

1. The restoration, by surgical or manipulative procedures, of a part to its normal anatomic relation. SYN: repositioning (2) . 2. In chemistry, a reaction involving a gain of one or more electrons by a substance, such as when iron passes from the ferric (3+) to the ferrous (2+) state, or when hydrogen is added to the double bond of an organic compound, or when an aldehyde is converted to an alcohol. [L. reductio, fr. re-duco, pp. ductus, to lead back]
r. of chromosomes the process during meiosis whereby one member of each homologous pair of chromosomes is distributed to a sperm or ovum; the diploid set of chromosomes (46 in humans) is thus reduced to the haploid set in each gamete; union of the sperm and ovum then restores the diploid or somatic number in the one-cell zygote.
closed r. of fractures r. by manipulation of bone, without incision in the skin.
r. en masse r. of hernial sac and contents, so that intestinal obstruction is still present.
open r. of fractures r. by manipulation of bone, after surgical exposure of the site of the fracture.
selective r. a technique for intrauterine termination of one or more fetuses while leaving one or more fetuses undisturbed, usually in pregnancies with fetal anomalies or with multiple gestations. SYN: selective termination.
tuberosity r. the surgical excision of excessive fibrous or bony tissue in the area of the maxillary tuberosity prior to the construction of prosthetic appliances.

redundancy
redundancy (re-dun′dans-e)

Occurrence of linearly arranged, largely identical, repeated sequences of DNA.
terminal r. the condition in a viral chromosome in which identical genetic information occurs at each end of the chromosome.

reduplication
reduplication (re′doo′pli-ka′shun)

1. A redoubling. 2. A duplication or doubling, as of the sounds of the heart in certain morbid states or the presence of two instead of a normally single part. 3. A fold or duplicature. [L. reduplicatio, fr. re-, again, + duplico, to double, fr. duplex, two-fold]

reduvid
reduvid, reduviid (re-doo′vid -vid)

A member of the family Reduviidae.

Reduviidae
Reduviidae (re-doo-vi′i-de)

A family (order Hemiptera) of predatory insects, the assassin bugs, which attack animals and humans. It includes the subfamily Triatominae, the kissing or cone-nosed bugs, whose type genus Triatoma includes species that are vectors of Trypanosoma cruzi.

Reed
Reed

Dorothy M., U.S. pathologist, 1874–1964. See R. cell, R.-Sternberg cell, Sternberg-R. cell.

Reed
Reed

Walter, 1851–1902. U.S. Army surgeon, elucidated epidemiology of yellow fever. See R.-Frost model.

reefing
reefing (ref′ing)

Surgically reducing the extent of a tissue by folding it and securing with sutures, as in plication.
stomach r. SYN: gastroplication.

reenactment
reenactment (re-en-akt′ment)

In psychodrama, the acting out of a past experience.

reentry
reentry (re-en′tre)

Return of the same impulse into a zone of heart muscle that it has recently activated, sufficiently delayed that the zone is no longer refractory, as seen in most ectopic beats, reciprocal rhythms, and most tachycardias.

Rees
Rees

H. Maynard, 20th century U.S. physician. See R.-Ecker fluid.

Reese
Reese

Algernon B., U.S. ophthalmologist, 1896–1981. See Cogan-R. syndrome.

refect
refect (re-fekt′)

To induce refection.

refection
refection (re-fek′shun)

A restoring to the normal state. [L. refectio, fr. reficere, to restore, fr. re- + facio, to do]

Refetoff
Refetoff

S., 20th century U.S. endocrinologist. See R. syndrome.

refine
refine (re-fin′)

To free from impurities.

reflect
reflect (re-flekt′)

1. To bend back. 2. To throw back, as of radiant energy from a surface. 3. To meditate; to think over a matter. 4. To send back a motor impulse in response to a sensory stimulus. [L. re- flecto, pp. -flexus, to bend back]

reflectance
reflectance

A measure of reflected acoustic energy as a function of immitance, as in middle ear impedance.

reflection
reflection (re-flek′shun)

1. The act of reflecting. 2. That which is reflected. 3. In psychotherapy, a technique in which a patient's statements are repeated, restated, or rephrased in order that the patient will continue to explore and expound on emotionally significant content. [L. reflexio, a bending back]

reflector
reflector (re-flek′ter)

Any surface that reflects light, heat, or sound.

reflex
reflex (re′fleks)

1. An involuntary reaction in response to a stimulus applied to the periphery and transmitted to the nervous centers in the brain or spinal cord. Most of the deep reflexes listed as subentries are stretch or myotatic reflexes, elicited by striking a tendon or bone, causing stretching, even slight, of the muscle, which then contracts as a result of the stimulus applied to its proprioceptors. SEE ALSO: phenomenon. 2. A reflection. [L. reflexus, pp. of reflecto, to bend back]
abdominal reflexes contraction of the muscles of the abdominal wall upon stimulation of the skin (superficial a. reflexs) or tapping neighboring bony structures (deep a. reflexs). SYN: supraumbilical r. (2) .
abdominocardiac r. mechanical stimulation (usually distention) of abdominal viscera causing changes (usually a slowing) in the heart rate or the occurrence of extrasystoles.
Abrams heart r. a contraction of the myocardium when the skin of the precordial region is irritated.
accommodation r. increased convexity of the lens, due to contraction of the ciliary muscle and relaxation of the suspensory ligament, to maintain a distinct retinal image.
Achilles r., Achilles tendon r. a contraction of the calf muscles when the tendo calcaneus is sharply struck. SYN: ankle jerk, ankle r., tendo Achillis r., triceps surae r..
acoustic r. contraction of the stapedius muscle in response to intense sound, increasing impedance of the middle ear and thereby protecting the inner ear from the sound. SYN: cochleostapedial r., stapedial r..
acousticopalpebral r. SYN: cochleopalpebral r..
acquired r. SYN: conditioned r..
acromial r. contraction of the biceps muscle caused by a tap on the acromion or the coracoid process.
adductor r. contraction of the adductors of the thigh caused by tapping the tendon of the adductor magnus muscle while the thigh is abducted.
allied reflexes reflexes that, acting toward a common purpose, can traverse the final common path together.
anal r. contraction of the internal sphincter gripping the finger passed into the rectum.
ankle r. SYN: Achilles r..
antagonistic reflexes reflexes that do not act toward a common purpose, and cannot together traverse the final common path.
aortic r. SYN: cardiac depressor r..
aponeurotic r. plantar flexion of the foot and toes elicited by tapping the sole near its outer edge; has the same significance as the Rossolimo toe flexion r.. SYN: Guillain-Barré r., sole tap r., Weingrow r..
Aschner r. SYN: oculocardiac r..
Aschner-Dagnini r. SYN: oculocardiac r..
attitudinal reflexes SYN: statotonic reflexes.
auditory r. any r. occurring in response to a sound, e.g., cochleopalpebral r..
auditory oculogyric r. rotation of the eyes toward the source of a sudden sound.
auricular r. a movement of the ears in animals in response to a sound; part of the investigatory r..
auriculopalpebral r. SYN: Kisch r..
auriculopressor r. peripheral vasoconstriction and a rise in blood pressure in response to a fall in pressure in the great veins. SYN: Pavlov r..
auropalpebral r. SYN: cochleopalpebral r..
axon r. a response elicited by peripheral nerve stimulation; attributed to impulses traveling proximally from the stimulation site along motor axons, encountering a branch point, and then passing distally down the other branch to activate local arterioles (to cause vasodilation) or muscle (to cause contractions). Latency of the response decreases with more proximal stimulation; axon r. is eliminated by axon degeneration or strong stimuli but not by proximal anesthetic blocks of the nerve.
Babinski r. SYN: Babinski sign (1) .
back of foot r., dorsum of foot r. SYN: Mendel instep r..
Bainbridge r. an increase in heart rate caused by a rise in pressure of the blood in the right atrium due to increased flow and/or pressure in the great veins at its entrance.
Barkman r. contraction of the ipsilateral rectus muscle in response to a stimulus applied to the skin below a nipple.
basal joint r. opposition and adduction of the thumb with flexion at its metacarpophalangeal joint and extension at its interphalangeal joint, when firm passive flexion of the third, fourth, or fifth finger is made; the r. is present normally but is absent in pyramidal lesions. SYN: finger-thumb r., Mayer r..
Bechterew-Mendel r. plantar flexion of the toes caused by percussion of the dorsum of the foot; present in a pyramidal lesion. SYN: dorsum pedis r., Mendel-Bechterew r..
behavior r. SYN: conditioned r..
Benedek r. plantar flexion of the foot caused by tapping the anterior margin of the lower part of the fibula, while the foot is slightly dorsiflexed.
Bezold-Jarisch r. a r. with afferent and efferent pathways in the vagus, originating in unidentified chemoreceptors in the heart and resulting in sinus bradycardia, hypotension, and probable peripheral vasodilation.
biceps r. contraction of the biceps muscle when its tendon is struck.
biceps femoris r. contraction of the biceps femoris upon tapping its lower part, just above its attachment to the head of the fibula, while the limb is partly flexed at hip and knee.
Bing r. when the foot is passively dorsiflexed, plantar flexion occurs if any point on the ankle between the two malleoli is tapped.
bladder r. SYN: micturition r..
blink r. blink response.
body righting reflexes r. effects upon the neck muscles that bring the head into the correct position in space caused by stimulation of pressoreceptors in the body wall by contact with the ground.
brachioradial r. with the arm supinated to 45°, a tap near the lower end of the radius causes contraction of the brachioradial (supinator longus) muscle. SYN: radioperiosteal r., styloradial r., supination r., supinator jerk, supinator r., supinator longus r..
Brain r. SYN: quadripedal extensor r..
bregmocardiac r. in infants, pressure upon the anterior fontanelle causing cardiac slowing.
Brissaud r. tickling the sole causes a contraction of the tensor fasciae latae muscle, even when there is no responsive movement of the toes.
bulbocavernosus r. a sharp contraction of the bulbocavernosus and ischiocavernosus muscles when the glans penis is suddenly compressed or tapped.
bulbomimic r. in a case of coma from severe apoplexy, pressure on the eyeballs causes contraction of the facial muscles of expression on the side opposite to the lesion; if coma due to diabetes, uremia, or other toxic cause the r. is present on both sides. SYN: facial r., Mondonesi r..
Capps r. obsolete eponym for vasomotor collapse at the time of crisis in pneumonia.
cardiac depressor r. a fall in blood pressure due to peripheral vasodilation and cardiac inhibition by stimulations of terminations of a cardiac depressor nerve in the aortic arch and base of the heart. SYN: aortic r., depressor r..
carotid sinus r. a normal r. relating to the carotid sinus syndrome, which results from hypersensitivity or hyperactivation of the carotid sinus.
celiac plexus r. arterial hypotension coincident with surgical manipulations in the upper abdomen during general anesthesia.
cephalopalpebral r. contraction of the orbicularis muscle elicited by tapping the vertex of the skull.
Chaddock r. SYN: Chaddock sign.
chain r. a series of r.s, each serving as a stimulus for the next.
chin r. SYN: jaw r..
Chodzko r. contractions of several muscles of the shoulder girdle and arm when the manubrium sterni is percussed.
ciliospinal r. SYN: pupillary-skin r..
clasping r. the strong flexion of the forelimbs of amphibia and certain other animals during the mating season when the chest or abdomen is stimulated; it is dependent upon the male sex hormone.
cochleo-orbicular r. SYN: cochleopalpebral r..
cochleopalpebral r. a form of the wink r. in which there is a contraction, sometimes very slight, of the orbicularis palpebrarum muscle to an intense sound. SEE ALSO: startle r.. SYN: acousticopalpebral r., auropalpebral r., cochleo-orbicular r..
cochleopupillary r. mydriasis in response to a sudden and unexpected loud noise; a normal response.
cochleostapedial r. SYN: acoustic r..
conditioned r. (CR) a r. that is gradually developed by training and association through the frequent repetition of a definite stimulus. See conditioning. SYN: acquired r., behavior r., trained r..
conjunctival r. closure of the eyes in response to irritation of the conjunctiva.
consensual light r. SYN: consensual reaction.
contralateral r. SYN: Brudzinski sign (1) .
corneal r. 1. a contraction of the eyelids when the cornea is lightly touched with a camel-hair pencil; SYN: lid r.. 2. reflection of light from the surface of the cornea.
costal arch r. contraction of the rectus abdominis muscle by tapping the costal margin inside the mammary line.
costopectoral r. SYN: pectoral r..
cough r. the r. that mediates coughing in response to irritation of the larynx or tracheobronchial tree. SYN: laryngeal r..
craniocardiac r. stimulation of nerve endings of certain cranial nerves ( e.g., olfactory, ophthalmic branch of trigeminal), with resultant cardiac depressor r., manifested by bradycardia and hypotension, through the cardiac branch of the vagus.
cremasteric r. a drawing up of the scrotum and testicle of the same side when the skin over the Scarpa triangle or on the inner side of the thigh is scratched.
crossed r. a r. movement on one side of the body in response to a stimulus applied to the opposite side. SYN: crossed jerk.
crossed adductor r. contraction of the adductors of the thigh and inward rotation of the limb elicited by tapping the sole. SYN: crossed adductor jerk.
crossed extension r. extension of the contralateral hind limb when the paw of an animal is painfully stimulated or the central cut end of an afferent nerve, e.g., the peroneal, is stimulated; sometimes occurs in humans upon tapping the skin.
crossed knee r. contraction of the contralateral quadriceps when a patellar r. is elicited. SYN: crossed knee jerk.
crossed r. of pelvis contraction of the contralateral adductors of the thigh upon tapping the anterior superior iliac spine. SYN: crossed spino-adductor r..
crossed spino-adductor r. SYN: crossed r. of pelvis.
cuboidodigital r. flexion of the toes on tapping over the cuboid bone; almost identical with Guillain-Barré r., and fundamentally similar to Rossolimo r.. SYN: metatarsal r..
cutaneous r. wrinkling of the skin, caused by a cutaneous stimulus, due to contraction of arrectores pilorum muscles.
cutaneous pupil r., cutaneous-pupillary r. SYN: pupillary-skin r..
darwinian r. the tendency of young infants to grasp a bar and hang suspended. Cf.:grasping r..
deep r. an involuntary muscular contraction following percussion of a tendon or bone. SYN: jerk (2) .
deep abdominal reflexes contraction of abdominal muscles elicited by stimulation, such as tapping a deep structure; e.g., the costal margin. SEE ALSO: Galant r., upper abdominal periosteal r..
deep tendon r. (DTR) SYN: myotatic r..
defense r. 1. SYN: flexor r.. 2. automatic reactions of an animal, e.g., raising of hair or feathers, dilation of the pupils, or baring of claws, when alarmed.
deglutition r. SYN: swallowing r..
Dejerine r. SYN: Dejerine hand phenomenon.
delayed r. a r. in which a little time elapses between stimulus and response. SEE ALSO: trace conditioned r..
depressor r. SYN: cardiac depressor r..
diffused r. one of several reflexes occurring in association with the main r..
digital r. SYN: Hoffmann sign (2) .
diving r. a r. by which immersing the face or body in water, especially cold water, tends to cause bradycardia and peripheral vasoconstriction; mean aortic pressure is little affected because the reduction in cardiac output tends to balance the increased peripheral resistance that reduces peripheral blood flow. Although relatively minor in most humans, the changes can be profound in some diving species of animal, e.g., ducks and seals.
dorsal r. contraction of the muscles of the back elicited by cutaneous stimulation over the erector spinal muscle.
dorsum pedis r. SYN: Bechterew-Mendel r..
elbow r. SYN: triceps r..
enterogastric r. peristaltic contraction of the small intestine induced by the entrance of food into the stomach. SEE ALSO: gastrocolic r..
epigastric r. a contraction of the upper portion of the rectus abdominis muscle when the skin of the epigastrium above is scratched. SYN: supraumbilical r. (1) .
erector-spinal r. a contraction of part of the erector spinae muscle following scratching of the skin on its outer border.
esophagosalivary r. salivation caused by irritation of the lower end of the esophagus, as by carcinoma. SYN: Roger r..
external oblique r. contraction of the external oblique and rectus abdominis muscles upon tapping the anterior and outer part of the lower thoracic wall.
eye r. SYN: light r. (2) .
eyeball compression r. SYN: eyeball-heart r..
eyeball-heart r. slowing of the heart rate due to the vagal effects of compressing an eyeball. SYN: eyeball compression r..
eye-closure r. SYN: wink r..
facial r. SYN: bulbomimic r..
faucial r. SYN: gag r..
femoral r. scratching the skin of the upper part of the front of the thigh causes extension of the knee and flexion of the foot.
femoroabdominal r. contraction of the abdominal muscles upon stroking the inner aspect of the thigh; in association with the cremasteric r.. SYN: hypogastric r..
Ferguson r. enhancement of uterine activity due to mechanical stretching of the lower uterine segment and cervix.
finger-thumb r. SYN: basal joint r..
flexor r. flexion of ankle, knee, and hip when the foot is painfully stimulated; the crossed extension r. occurs in association with it. SYN: defense r. (1) , nociceptive r., withdrawal r..
forced grasping r. SYN: grasping r..
front-tap r. contraction of the gastrocnemius muscle when the shin is struck. SYN: periosteal r. (1) .
fundus r. SYN: light r. (2) .
gag r. contact of a foreign body with the mucous membrane of the fauces causes retching or gagging. SYN: faucial r..
Galant r. a deep abdominal r. in which there is a contraction of the abdominal muscles on tapping the anterior superior iliac spine. SYN: lower abdominal periosteal r..
galvanic skin r. SYN: galvanic skin response.
gastrocolic r. a mass movement of the contents of the colon, frequently preceded by a similar movement in the small intestine, that sometimes occurs immediately following the entrance of food into the stomach.
gastroileac r. opening of the ileocolic valve induced by entrance of food into the stomach.
Geigel r. in the female, a contraction of the muscular fibers at the upper edge of the Poupart ligament on gently stroking the inner side of the thigh; analogue of the cremasteric r. in males.
Gifford r. SYN: eye-closure pupil reaction.
gluteal r. contraction of the gluteal muscles following irritation of the skin of the buttocks.
Gordon r. dorsal flexion of the great toe produced by firm lateral pressure on the calf muscles. SYN: paradoxical flexor r..
grasp r. SYN: grasping r..
grasping r. an involuntary flexion of the fingers to tactile or tendon stimulation on the palm of the hand, producing an uncontrollable grasp; usually associated with frontal lobe lesions. Cf.:darwinian r.. SYN: forced grasping r., grasp r..
great-toe r. SYN: Babinski sign (1) .
Guillain-Barré r. SYN: aponeurotic r..
gustatory-sudorific r. sweating, especially over the face, when chewing food. SEE ALSO: auriculotemporal nerve syndrome.
H r. a monosynaptic r. consistently obtained in normal adults only by stimulating the tibial nerve, generally in the popliteal fossa, while recording from the gastrocnemius-soleus muscle group; similar to the Achilles r., except the neuromuscular spindles are bypassed; widely used in the EMG laboratory to diagnose S1 radiculopathies and polyneuropathies.
hepatojugular r. hepatojugular reflux.
Hering-Breuer r. the effects of afferent impulses from the pulmonary vagi in the control of respiration; e.g., inflation of the lungs arrests inspiration with expiration then ensuing, whereas deflation of the lungs brings on inspiration.
Hoffmann r. SYN: Hoffmann sign (2) .
hypochondrial r. a quick inspiration induced by sharp pressure beneath the costal margin.
hypogastric r. SYN: femoroabdominal r..
inborn r. SYN: innate r..
innate r. an unlearned or instinctive r. such as sucking, which is present at birth. SYN: inborn r..
interscapular r. SYN: scapular r..
intrinsic r. a r. muscular contraction elicited by the application of a stimulus, usually stretching, to the muscle itself as opposed to a muscular contraction caused by an extrinsic stimulus, e.g., skin, as in the abdominal skin reflexes.
inverted r. SYN: paradoxical r..
inverted radial r. flexion of the fingers without flexion of the forearm, on tapping the lower end of the radius; regarded as indicating a lesion of the fifth cervical segment of the spinal cord.
investigatory r. SYN: orienting r..
ipsilateral r. a r. in which the response occurs on the side of the body that is stimulated.
Jacobson r. flexion of the fingers elicited by tapping the flexor tendons over the wrist joint or the lower end of the radius.
jaw r. a spasmodic contraction of the temporal muscles following a downward tap on the loosely hanging mandible. SYN: chin jerk, chin r., jaw jerk, mandibular r., masseter r..
jaw-working r. SYN: jaw-winking syndrome.
Joffroy r. twitching of the glutei muscles when firm pressure is made on the nates, in cases of spastic paralysis. SYN: hip phenomenon.
Kisch r. closure of the eye in response to stimulation of the skin at the depth of the external auditory meatus. SYN: auriculopalpebral r..
knee r. SYN: patellar r..
knee-jerk r. SYN: patellar r..
labyrinthine reflexes reflexes initiated through stimulation of receptors in the utricle or semicircular canals. SEE ALSO: statotonic reflexes, statokinetic r., righting reflexes.
labyrinthine righting reflexes stimulation of the receptors of the labyrinth causes changes in tone of the neck muscles that bring the head into position.
lacrimal r. discharge of tears when the conjunctiva is irritated.
lacrimogustatory r. chewing of food causing secretion of tears. SEE ALSO: crocodile tears syndrome.
laryngeal r. SYN: cough r..
laryngospastic r. SYN: laryngospasm.
latent r. a r. that must be considered normal but that usually appears only under some pathologic circumstance that lowers its threshold.
laughter r. uncontrollable laughter excited by tickling.
let-down r. SYN: milk-ejection r..
lid r. SYN: corneal r. (1) .
Liddell-Sherrington r. SYN: myotatic r..
light r. 1. SYN: pupillary r.. 2. a red glow reflected from the fundus of the eye when a light is cast upon the retina, as in retinoscopy; SYN: eye r., fundus r.. 3. a triangular area at the anterior inferior part of the tympanic membrane, extending from the umbo to the periphery, where there is seen a reflection of light. SYN: cone of light, Politzer luminous cone, pyramid of light, red r., Wilde triangle.
lip r. a pouting movement of the lips provoked in young infants by tapping near the angle of the mouth.
Lovén r. a reaction in which a local dilation of vessels accompanies a general vasoconstriction; e.g., when the central end of an afferent nerve to an organ is suitably stimulated, its efferent vasomotor fibers remaining intact, a general rise in blood pressure occurs together with a dilation of the vessels of the organ.
lower abdominal periosteal r. SYN: Galant r..
magnet r. magnet reaction.
mandibular r. SYN: jaw r..
mass r. in cases of gross injury to the spinal cord, as the stage of r. activity follows the primary flaccidity of the shock, a condition arises in which a strong stimulus to any part of one of the paralyzed limbs will be followed by contraction of the hip, knee, and ankle of the same side and often, when the stimulus is applied to the middle line of the body, of both sides, as well as of the abdominal wall, and even evacuation of the bladder and sweating over an area corresponding to the level of the lesion.
masseter r. SYN: jaw r..
Mayer r. SYN: basal joint r..
McCarthy reflexes 1. SYN: spinoadductor r.. 2. SYN: supraorbital r..
mediopubic r. contraction of the adductors of the thigh upon tapping the pubic bone near the symphysis.
Mendel-Bechterew r. SYN: Bechterew-Mendel r..
Mendel instep r. the foot being firmly supported on its inner side, a sharp tap on the dorsal tendons causes extension of the second to the fifth toes. SYN: back of foot r., dorsum of foot r..
metacarpohypothenar r. flexion of the little finger on tapping the dorsum of the hand; seen in pyramidal tract lesions; similar to Starling r..
metacarpothenar r. SYN: thumb r..
metatarsal r. SYN: cuboidodigital r..
micturition r. contraction of the walls of the bladder and relaxation of the trigone and urethral sphincter in response to a rise in pressure within the bladder; the r. can be voluntarily inhibited and the inhibition readily abolished to control micturition. SYN: bladder r., urinary r., vesical r..
milk-ejection r. release of milk from the breast following tactile stimulation of the nipple; the afferent path is postulated to exist from the nipple to the hypothalamus; the efferent limb is represented by the neurohypophysial release of oxytocin into the systemic circulation; contraction of myoepithelial elements within the breast, caused by oxytocin, moves milk into the collecting ducts and toward the nipple. SYN: let-down r., milk let-down r..
milk let-down r. SYN: milk-ejection r..
Mondonesi r. SYN: bulbomimic r..
Moro r. SYN: startle r..
muscular r. SYN: myotatic r..
myenteric r. contraction above and relaxation below a stimulated point in the intestine. SYN: law of intestine.
myotatic r. tonic contraction of the muscles in response to a stretching force, due to stimulation of muscle proprioceptors. SYN: deep tendon r., Liddell-Sherrington r., muscular r., stretch r..
nasal r. sneezing caused by irritation of the nasal mucous membrane.
nasomental r. contraction of the mentalis muscle following a tap on the side of the nose.
near r. pupillary constriction with a near vision effort, with ocular convergence, or with accommodation; an associated reaction, not a true r..
neck reflexes changes in position of the head cause alterations in tone of the neck muscles through stimulation of proprioceptors in the labyrinth which bring the head into its correct position in space; stimulation of proprioceptors in the neck muscles causes in turn r. movements of the limbs which bring the animal into the normal position in relation to the head.
nociceptive r. SYN: flexor r..
nocifensor r. vascular dilation in a part surrounding an injury or in its neighborhood.
nose-bridge-lid r. SYN: orbicularis oculi r..
nose-eye r. SYN: orbicularis oculi r..
oculocardiac r. a decrease in pulse rate associated with traction on extraocular muscles or compression of the eyeball; especially sensitive in children; may produce asystolic cardiac arrest. SYN: Aschner phenomenon, Aschner r., Aschner-Dagnini r..
oculocephalic r. SYN: oculocephalogyric r..
oculocephalogyric r. turning of the eyes and head toward the source of an auditory, visual, or other form of stimulation. SYN: oculocephalic r..
oculovagal r. See oculocardiac r..
olecranon r. flexion of the forearm caused by tapping the olecranon. SYN: paradoxical triceps r..
Oppenheim r. extension of the toes induced by scratching of the inner side of the leg or by following sudden flexion of the thigh on the abdomen and the leg on the thigh; a sign of cerebral irritation.
optical righting reflexes visual stimuli that enable an animal to maintain the correct position of the head in space, by bringing about movements of the muscles of the neck and limbs.
orbicularis oculi r. contraction of the orbicularis oculi muscles upon tapping the margin of the orbit, or the bridge or tip of the nose. SYN: nose-bridge-lid r., nose-eye r..
orbicularis pupillary r. SYN: eye-closure pupil reaction.
orienting r. an aspect of attending in which an organism's initial response to a change or to a novel stimulus is such that the organism becomes more sensitive to the stimulation; e.g., dilation of the pupil of the eye in response to dim light. SYN: investigatory r., orienting response.
palatal r., palatine r. swallowing r. induced by stimulation of the palate.
palmar r. flexion of the fingers following tickling of the palm.
palm-chin r. SYN: palmomental r..
palmomental r. unilateral (sometimes bilateral) contraction of the mentalis and orbicularis oris muscles caused by a brisk scratch made on the palm of the ipsilateral hand. SYN: palm-chin r..
parachute r. SYN: startle r..
paradoxical r. any r. in which the usual response is reversed or does not conform to the pattern characteristic of the particular r.. SYN: inverted r..
paradoxical extensor r. SYN: Babinski sign (1) .
paradoxical flexor r. SYN: Gordon r..
paradoxical patellar r. 1. a tap on the patellar tendon causes contraction of the adductor; 2. sudden passive extension of the leg causes a contraction of the extensor muscles of the leg.
paradoxical pupillary r. constriction of pupils in darkness, the reverse of that expected. SYN: Flynn phenomenon, paradoxical pupillary phenomenon.
paradoxical triceps r. SYN: olecranon r..
patellar r. a sudden contraction of the anterior muscles of the thigh, caused by a smart tap on the patellar tendon while the leg hangs loosely at a right angle with the thigh. SYN: knee jerk, knee r., knee-jerk r., patellar tendon r., quadriceps r..
patellar tendon r. SYN: patellar r..
patelloadductor r. crossed adduction of the leg on tapping the quadriceps tendon.
Pavlov r. SYN: auriculopressor r..
pectoral r. contraction of the pectoralis major muscle elicited by tapping the seventh rib between the anterior and the medial axillary lines while the arm is abducted; contraction of the deltoid and biceps may also occur. SYN: costopectoral r..
Perez r. running a finger down the spine of an infant held supported in a prone position will normally cause the whole body to become extended.
pericardial r. a vagal r. seen during operations involving pericardial manipulation; characterized by signs of vagal stimulation (bradycardia and arterial hypotension).
periosteal r. 1. SYN: front-tap r.. 2. a muscular contraction in the arm following a tap on the radius or ulna.
pharyngeal r. 1. SYN: swallowing r.. 2. SYN: vomiting r..
phasic r. a coordinated complex response such as the scratch r. in the spinal animal.
Phillipson r. a contraction of the extensors of the knee when the extensors of the opposite knee are inhibited.
photic-sneeze r. SYN: photoptarmosis.
pilomotor r. contraction of the smooth muscle of the skin resulting in “gooseflesh” caused by mild application of a tactile stimulus or by local cooling.
plantar r. the response to tactile stimulation of the ball of the foot, normally plantar flexion of the toes; the pathologic response is Babinski sign (1) . SYN: sole r..
plantar muscle r. SYN: Rossolimo r..
pneocardiac r. a modification in the blood pressure or heart rhythm caused by the inhalation of an irritating vapor.
pneopneic r. a modification of the respiratory rhythm caused by the inhalation of an irritating vapor.
postural r. responses that control the position of the trunk and extremities. SEE ALSO: righting reflexes. SYN: static reflexes (1) .
pressoreceptor r. a normal r. related to the carotid sinus syndrome.
pronator r. SYN: ulnar r..
proprioceptive reflexes any r. brought about by stimulation of proprioceptors. SEE ALSO: proprioceptor.
proprioceptive-oculocephalic r. SYN: vestibuloocular r..
protective laryngeal r. closure of the glottis to prevent entry of foreign substances into the respiratory tract.
psychocardiac r. a change in the circulatory rate and subjective heart consciousness (often “thumping”) resulting from a memory of, or a subconscious dream state recollection of, an emotional impression or experience.
psychogalvanic r., psychogalvanic skin r. SYN: galvanic skin response.
pulmonocoronary r. r. constriction of the coronary arteries as a result of vagal stimuli arising in the lungs, as in pulmonary embolism.
pupillary r. change in diameter of the pupil as a r. response to any type of stimulus; e.g., constriction caused by light. SYN: light r. (1) .
pupillary-skin r. dilation of the pupil following scratching of the skin of the neck. SYN: ciliospinal r., cutaneous pupil r., cutaneous-pupillary r., skin-pupillary r..
quadriceps r. SYN: patellar r..
quadripedal extensor r. extension of the arm of a hemiplegic patient when turned prone as if on all fours. SYN: Brain r..
radial r. on tapping the lower end of the radius, flexion of the forearm occurs, and sometimes, on strong percussion, flexion of the fingers. SEE ALSO: inverted radial r..
radiobicipital r. contraction of the biceps muscle that sometimes occurs in the elicitation of the brachioradial r..
radioperiosteal r. SYN: brachioradial r..
rectal r. the entrance of fecal matter into the rectum from the sigmoid colon causes an impulse to defecate.
rectocardiac r. a parasympathetic r. producing bradycardia and hypotension upon stimulation of the pelvic nerve, the afferent limb being the sacral outflow of the parasympathetic division of the autonomic nervous system, and the efferent limb, the cardiac vagus; said to accompany proctologic examinations.
rectolaryngeal r. laryngeal spasm precipitated by stretching the anal sphincter.
red r. SYN: light r. (3) .
Remak r. plantar flexion of the first three toes and, sometimes, the foot with extension of the knee induced by stroking of the upper anterior surface of the thigh; it occurs when the conducting paths in the cord are interrupted.
renal r. anuria caused by injury to a remote part of the body or by disease or injury to one kidney or ureter.
righting reflexes reflexes that through various receptors, in labyrinth, eyes, muscles, or skin tend to bring an animal's body into its normal position in space and that resist any force acting to put it into a false position, e.g., on its back. SEE ALSO: body righting reflexes, labyrinthine righting reflexes, neck reflexes, optical righting reflexes. SYN: static reflexes (2) .
Roger r. SYN: esophagosalivary r..
rooting r. in infants, rubbing or scratching about the mouth causes a puckering of the lips.
Rossolimo r. flicking the tops of the toes from the plantar surface causes flexion of the toes; a stretch r. of the flexors of the toes seen in lesions of the pyramidal tracts. SEE ALSO: Starling r.. SYN: plantar muscle r., Rossolimo sign.
scapular r. contraction of the upper muscles of the back by stimulation between the scapulae. SYN: interscapular r..
scapulohumeral r. contraction of muscles of the shoulder girdle and arm caused by tapping the lower part of the unilateral border of the scapula; the muscles that respond vary according to their degree of stretching at the time. SYN: scapuloperiosteal r..
scapuloperiosteal r. SYN: scapulohumeral r..
Schäffer r. in cases of injury to the corticospinal tract, the great toe is dorsiflexed when the skin over the Achilles tendon is pinched.
semimembranosus r., semitendinosus r. contraction of these muscles by tapping in the region of the tuberosity of the tibia.
shot-silk r. SYN: shot-silk retina.
sinus r. carotid sinus syndrome.
skin reflexes SYN: skin-muscle reflexes.
skin-muscle reflexes superficial or cutaneous reflexes, such as the superficial abdominal reflexes. SYN: skin reflexes.
skin-pupillary r. SYN: pupillary-skin r..
snapping r. SYN: Hoffmann sign (2) .
snout r. pouting or pursing of the lips induced by light tapping of the closed lips in the midline; considered a sign of frontal lobe dysfunction.
sole r. SYN: plantar r..
sole tap r. SYN: aponeurotic r..
spinal r. a r. arc involving the spinal cord. See r. arc.
spinoadductor r. contraction of the adductors of the thigh upon tapping the spinal column. SYN: McCarthy reflexes (1) .
stapedial r. SYN: acoustic r..
Starling r. tapping the volar surfaces of the fingers causes flexion of the fingers; analogous to Rossolimo r., for the toes.
startle r. the r. response of an infant (contraction of the limb and neck muscles) when allowed to drop a short distance through the air or startled by a sudden noise or jolt; SYN: Moro r., parachute r., startle reaction. SEE ALSO: cochleopalpebral r..
static reflexes 1. SYN: postural r.. 2. SYN: righting reflexes.
statokinetic r. a r. that, through stimulation of the receptors in the neck muscles and semicircular canals, brings about movements of the limbs and eyes appropriate to a given movement of the head in space.
statotonic reflexes reflexes in which utricular receptors in the vestibular apparatus sense changes in the head's position in space in terms of linear acceleration and the earth's gravitational field while receptors in the neck muscles sense changes in the position of the head relative to the trunk; input from these receptors reflexly controls the tone of the limb muscles to maintain or regain the desired posture. SYN: attitudinal reflexes.
sternobrachial r. contraction of the adductors of the arm when the sternum is tapped.
stretch r. SYN: myotatic r..
Strümpell r. stroking the abdomen or thigh causes flexion of the leg and adduction of the foot.
styloradial r. SYN: brachioradial r..
suckling r. the r. liberation of prolactin from the anterior lobe of the hypophysis evoked by stimulation of nerves in the nipple during the act of suckling by the newborn animal.
superficial r. any r., e.g., the abdominal or cremasteric r., that is elicited by stimulation of the skin.
supination r. SYN: brachioradial r..
supinator r., supinator longus r. SYN: brachioradial r..
supporting reflexes SYN: supporting reactions, under reaction.
supraorbital r. contraction of the orbicularis oculi muscle induced by electrical or mechanical stimulation of the supraorbital nerve. SYN: McCarthy reflexes (2) , trigeminofacial r..
suprapatellar r. the patella rises when a tap is given on the quadriceps tendon above the patella.
supraumbilical r. 1. SYN: epigastric r.. 2. SYN: abdominal reflexes.
swallowing r. the act of swallowing (second stage) induced by stimulation of the palate, fauces, or posterior pharyngeal wall. SYN: deglutition r., pharyngeal r. (1) .
synchronous r. subsidiary r. actions occurring in association with the main or leading r..
tarsophalangeal r. extension of all the toes except the first, when the outer part of the tarsus is tapped; in certain cerebral diseases the reverse takes place, the toes being flexed.
tendo Achillis r. SYN: Achilles r..
tendon r. a myotatic or deep r. in which the muscle stretch receptors are stimulated by percussing the tendon of a muscle.
tensor tympani r. contraction of the tensor tympani muscle in response to intense sound, increasing impedance of the middle ear and thus protecting the inner ear from exposure.
thumb r. flexion of the thumb upon tapping the dorsum of the hand. SYN: metacarpothenar r..
tonic r. the occurrence of an appreciable interval after the production of a r. before relaxation, e.g., the leg remains up for a time after a knee jerk. SYN: Gordon symptom.
trace conditioned r. a conditioned r. established by applying the stimulus a short time before reinforcement; in the conditioned r. of the animal so prepared, the response occurs at the same interval of time after the application of the stimulus as during the period of training.
trained r. SYN: conditioned r..
triceps r. a sudden contraction of the triceps muscle caused by a smart tap on its tendon when the forearm hangs loosely at a right angle with the arm. SYN: elbow jerk, elbow r..
triceps surae r. SYN: Achilles r..
trigeminofacial r. SYN: supraorbital r..
trochanter r. contraction of the adductor muscles of the thigh elicited by a tap on the trochanter.
Trömner r. a modified Rossolimo r. in which, with the fingers of the patient partially flexed, the tapping of the volar aspect of the tip of the middle or index finger causes flexion of all four fingers and thumb; seen in pyramidal tract lesions with moderate spasticity.
ulnar r. pronation and adduction of the hand caused by tapping the styloid process of the ulna. SYN: pronator r..
unconditioned r. an instinctive r. not dependent on previous learning or experience.
upper abdominal periosteal r. percussing the lower margin of the costal cartilages in the nipple line causes a contraction of the ipsilateral abdominal muscles (inconstant).
urinary r. SYN: micturition r..
utricular reflexes statotonic reflexes.
vagovagal r. bradycardia with arterial hypotension, often with supraventricular arrhythmias; ascribed to stimulation, especially mechanical, of afferent vagal pathways in the abdomen, thorax, or airway, the efferent arc being vagal cardioinhibitory fibers.
vasopressor r. vasoconstriction caused by stimulation of certain afferent fibers, e.g., in vagus nerve.
venorespiratory r. stimulation of respiration and increased pulmonary ventilation in response to an increase in pressure in the right atrium.
vesical r. SYN: micturition r..
vestibuloocular r. generic term for the r. control of the vestibular system over extraocular motility manifest as nystagmus in clinical testing. SYN: proprioceptive-oculocephalic r..
vestibulospinal r. the influence of vestibular stimulation on body posture.
visceral traction r. laryngeal spasm precipitated during an operation by traction on the stomach, gallbladder, or appendiceal mesentery.
viscerogenic r. any of a number of reflexes, such as headache, cough, disturbed pulse, etc., caused by disordered conditions of any of the viscera.
visceromotor r. contraction of the muscles of the thorax or abdomen in response to a stimulus from one of the viscera therein.
viscerosensory r. an area of pain or sensitivity to pressure in the external body wall due to disease of one of the viscera. SEE ALSO: Head lines, under line.
viscerotrophic r. a degenerative change in the skeletal soft tissues consequent upon a chronic inflammatory condition of any of the thoracic or abdominal viscera.
visual orbicularis r. contraction of the orbicularis oculi muscle caused by a sudden visual stimulus. SEE ALSO: wink r..
vomiting r. vomiting (contraction of the abdominal muscles with relaxation of the cardiac sphincter of the stomach and of the muscles of the throat) elicited by a variety of stimuli, especially one applied to the region of the fauces. SYN: pharyngeal r. (2) .
Weingrow r. SYN: aponeurotic r..
Westphal pupillary r. SYN: eye-closure pupil reaction.
white pupillary r. SYN: leukocoria.
wink r. general term for r. closure of eyelids caused by any stimulus. SYN: eye-closure r..
withdrawal r. SYN: flexor r..
wrist clonus r. sudden extension of the wrist induces a sustained clonic movement.

reflexogenic
reflexogenic (re-flek-so-jen′ik)

Causing a reflex. SYN: reflexogenous.

reflexogenous
reflexogenous (re-flek-soj′e-nus)

SYN: reflexogenic.

reflexograph
reflexograph (re-flek′so-graf)

An instrument for graphically recording a reflex. [reflex + G. grapho, to write]

reflexology
reflexology (re-flek-sol′o-je)

The study of reflexes. [reflex + G. logos, study]

reflexometer
reflexometer (re-flek-som′e-ter)

An instrument for measuring the force necessary to excite a reflex. [reflex + G. metron, measure]

reflexophil
reflexophil, reflexophile (re-flek′so-fil, -fil)

Having exaggerated reflexes. [reflex + G. phileo, to love]

reflexotherapy
reflexotherapy (re-flek′so-thar′a-pe)

SYN: reflex therapy.

reflux
reflux (re′fluks)

1. A backward flow. SEE ALSO: regurgitation. 2. In chemistry, to boil without loss of vapor because of the presence of a condenser that returns vapor as liquid. [L. re-, back, + fluxus, a flow]
abdominojugular r. SYN: hepatojugular r..
esophageal r., gastroesophageal r. regurgitation of the contents of the stomach into the esophagus, possibly into the pharynx where they can be aspirated between the vocal cords and down into the trachea; symptoms of burning pain and acid taste result; pulmonary complications of aspiration are dependent upon the amount, content, and acidity of the aspirate.
hepatojugular r. an elevation of venous pressure visible in the jugular veins and measurable in the veins of the arm, produced in active or impending congestive heart failure and constrictive pericarditis by firm pressure with the flat hand over the abdomen. Often called hepatojugular r. when pressure is exclusively over the liver. SYN: abdominojugular r..
intrarenal r. urinary r. from renal pelvis and calices into the collecting ducts. This is seen as a blush of the renal pyramid on voiding cystourethrography. SYN: pyelotubular r..
pyelotubular r. SYN: intrarenal r..
ureterorenal r. backward flow of urine from ureter into renal pelvis.
vesicoureteral r. backward flow of urine from bladder into ureter.

reformat
reformat (re-for′mat)

In computed tomography, when data from a series of contiguous transverse scan images are recombined to produce images in a different plane, such as sagittal or coronal.

refract
refract (re-frakt′)

1. To change the direction of a ray of light. 2. To detect an error of refraction and to correct it by means of lenses. [L. refringo, pp. -fractus, to break up]

refractable
refractable (ri-frak′ta-bil)

Subject to refraction. SYN: refrangible.

refraction
refraction (re-frak′shun)

1. The deflection of a ray of light when it passes from one medium into another of different optical density; in passing from a denser into a rarer medium it is deflected away from a line perpendicular to the surface of the refracting medium; in passing from a rarer to a denser medium it is bent toward this perpendicular line. 2. The act of determining the nature and degree of the refractive errors in the eye and correction of the same by lenses. SYN: refringence. [L. refractio (see refract)]
double r. the property of having more than one refractive index according to the direction of the transmitted light. SYN: birefringence.
dynamic r. r. of the eye during accommodation.
static r. r. without accommodation.

refractionist
refractionist (re-frak′shun-ist)

A person trained to measure the refraction of the eye and to determine the proper corrective lenses.

refractionometer
refractionometer (re-frak-shun-om′e-ter)

SYN: refractometer.

refractive
refractive (re-frak′tiv)

1. Pertaining to refraction. 2. Having the power to refract. SYN: refringent.

refractivity
refractivity (re-frak-tiv′i-te)

Refractive power. SYN: refringency.

refractometer
refractometer (re-frak-tom′e-ter)

An instrument for measuring the degree of refraction in translucent substances, especially the ocular media. See refractive index. SYN: objective optometer, refractionometer. [refraction + G. metron, measure]

refractometry
refractometry (re-frak-tom′e-tre)

1. Measurement of the refractive index. 2. Use of a refractometer to determine the refractive error of the eye.

refractory
refractory (re-frak′tor-e)

1. Resistant to treatment, as of a disease. SYN: intractable (1) , obstinate (2) . 2. SYN: obstinate (1) . [L. refractarius, fr. refringo, pp. -fractus, to break in pieces]

refracture
refracture (re-frak′choor)

Breaking a bone that has united after a previous fracture with the new fracture occurring at or near the previous fracture site. [re- + fracture]

refrangible
refrangible (re-fran′ji-bl)

SYN: refractable. [L. refringo, to break in pieces]

refresh
refresh (re-fresh′)

1. To renew; to cause to recuperate. 2. To perform revivification (2). [O. Fr. re-frescher]

refrigerant
refrigerant (re-frij′er-ant)

1. Cooling; reducing slight fever. 2. An agent that gives a sensation of coolness or relieves feverishness. [L. re-frigero, pp. -atus, pr. p. -ans, to make cold, fr. frigus (frigor-), cold]

refrigeration
refrigeration (re-frij-er-a′shun)

The act of cooling or reducing fever. [L. refrigeratio (see refrigerant)]

refringence
refringence (re-frin′jens)

SYN: refraction.

refringency
refringency (re-frin′jen-se)

SYN: refractivity.

refringent
refringent (re-frin′jent)

SYN: refractive.

Refsum
Refsum

Sigvald, Norwegian neurologist, *1907. See R. disease, R. syndrome.

refusion
refusion (re-foo′zhun)

Return of the circulation of blood which has been temporarily cut off by ligature of a limb. [L. re-fundo, pp. -fusus, to pour back]

regainer
regainer (re-gan′er)

An appliance used in an attempt to regain space in the dental arches.

Regaud
Regaud

Claude, French radiologist, 1870–1940. See R. fixative, residual body of R..

regenerate
regenerate (re-jen′er-at)

To renew; to reproduce. [L. re- genero, pp. -atus, to reproduce, fr. genus (gener-), birth, race]

regeneration
regeneration (re′jen-er-a′shun)

1. Reproduction or reconstitution of a lost or injured part. SYN: neogenesis. 2. A form of asexual reproduction; e.g., when a worm is divided into two or more parts, each segment is regenerated into a new individual. [L. regeneratio (see regenerate)]
aberrant r. misdirected regrowth of nerve fibers seen, for example, after oculomotor nerve injury. SYN: misdirection phenomenon.
guided tissue r. r. of tissue directed by the physical presence and/or chemical activities of a biomaterial; often involves placement of barriers to exclude one or more cell types during healing or r. of tissue.

regimen
regimen (rej′i-men)

A program, including drugs, which regulates aspects of one's lifestyle for a hygienic or therapeutic purpose; a program of treatment; sometimes mistakenly called regime. [L. direction, rule]

regio
regio, gen. regionis, pl .regiones (re′je-o, -o′nis, -o′nez) [TA]

SYN: region. [L.]
regiones abdominis [TA] SYN: abdominal regions, under region.
r. abdominis lateralis flank.
r. analis [TA] SYN: anal triangle.
r. antebrachialis anterior anterior region of forearm.
r. antebrachialis posterior posterior region of forearm.
r. antebrachii anterior [TA] SYN: anterior region of forearm.
r. antebrachii posterior [TA] SYN: posterior region of arm.
r. axillaris [TA] SYN: axillary region.
r. brachialis anterior anterior region of arm.
r. brachialis posterior posterior region of arm.
r. brachii anterior [TA] SYN: anterior region of arm.
r. buccalis [TA] SYN: buccal region.
r. calcanea [TA] SYN: heel region.
regiones capitis [TA] SYN: regions of head, under region.
r. carpalis anterior [TA] SYN: anterior region of wrist.
r. carpalis posterior [TA] SYN: posterior region of wrist.
regiones cervicales [TA] SYN: regions of neck, under region.
r. cervicalis anterior [TA] SYN: anterior cervical region.
r. cervicalis lateralis [TA] SYN: lateral cervical region.
r. cervicalis posterior [TA] SYN: posterior cervical region.
r. colli posterior posterior cervical region.
regiones corporis SYN: regions of body, under region.
r. cruralis posterior [TA] SYN: posterior region of leg.
r. cruris anterior [TA] SYN: anterior region of leg.
r. cubitalis anterior [TA] SYN: anterior region of elbow.
r. cubitalis posterior posterior region of elbow.
r. deltoidea [TA] SYN: deltoid region.
regiones dorsales [TA] SYN: regions of back, under region.
regiones dorsi regions of back, under region.
r. epigastrica epigastric region.
r. facialis [TA] SYN: face region.
r. femoralis posterior SYN: posterior region of thigh.
r. femoris [TA] SYN: femoral region.
r. femoris anterior [TA] SYN: anterior region of thigh.
r. femoris posterior [TA] SYN: posterior region of thigh.
r. frontalis capitis [TA] SYN: frontal region of head.
r. genus anterior [TA] SYN: anterior region of knee.
r. genus posterior [TA] SYN: posterior region of knee.
r. glutealis [TA] SYN: gluteal region.
r. hypochondriaca hypochondriac region.
r. infraclavicularis SYN: infraclavicular fossa.
r. inframammaria [TA] SYN: inframammary region.
r. infraorbitalis [TA] SYN: infraorbital region.
r. infrascapularis [TA] SYN: infrascapular region.
r. inguinalis groin (1) .
r. lateralis abdominis flank.
r. lumbalis [TA] SYN: lumbar region.
r. mammaria [TA] SYN: mammary region.
regiones membri inferioris [TA] SYN: regions of lower limb, under region.
regiones membri superioris [TA] SYN: regions of upper limb, under region.
r. mentalis [TA] SYN: mental region.
r. nasalis [TA] SYN: nasal region.
r. nuchalis SYN: posterior cervical region.
r. occipitalis capitis [TA] SYN: occipital region of head.
r. olfactoria tunicae mucosae nasi SYN: olfactory region of nasal mucosa.
r. oralis [TA] SYN: oral region.
r. orbitalis [TA] SYN: orbital region.
r. parietalis capitis [TA] SYN: parietal region.
r. pectoralis [TA] SYN: pectoral region.
r. perinealis [TA] SYN: perineal region.
r. plantaris sole of foot.
r. presternalis [TA] SYN: presternal region.
r. pubica pubic region.
r. respiratoria tunicae mucosae nasi SYN: respiratory region of mucosa of nasal cavity.
r. sacralis [TA] SYN: sacral region.
r. scapularis [TA] SYN: scapular region.
r. sternocleidomastoidea [TA] SYN: sternocleidomastoid region.
r. suralis [TA] SYN: sural region, sural region.
r. talocruralis SYN: ankle region.
r. tarsalis [TA] SYN: ankle region.
r. temporalis capitis [TA] SYN: temporal region of head.
regiones thoracicae anteriores et laterales [TA] SYN: anterior and lateral thoracic regions, under region.
r. umbilicalis [TA] SYN: umbilical region.
r. urogenitalis [TA] SYN: urogenital triangle.
r. vertebralis [TA] SYN: vertebral region.
r. zygomatica [TA] SYN: zygomatic region.

region
region (re′jun) [TA]

1. An often arbitrarily limited portion of the surface of the body. SEE ALSO: space, zone. 2. A portion of the body having a special nervous or vascular supply, or a part of an organ having a special function. SEE ALSO: area, space, spatium, zone. SYN: regio [TA] . [L. regio]
abdominal regions [TA] the topographic subdivisions of the abdomen; based on subdividing the abdomen by the transpyloric, interspinous, and midclavicular planes; including the right and left hypochondrium, right and left flank or lateral, right and left groin or inguinal, and the unpaired epigastric, umbilical, and pubic regions. SYN: regiones abdominis [TA] , abdominal zones.
anal r. SYN: anal triangle.
ankle r. [TA] the r. of the lower limb between the leg (crus) and the foot (pes). SYN: regio tarsalis [TA] , regio talocruralis.
anterior antebrachial r. SYN: anterior r. of forearm.
anterior r. of arm [TA] area between deltoid r. superiorly and anterior r. of elbow inferiorly. SYN: regio brachii anterior [TA] , regio brachialis anterior&star, anterior surface of arm, facies anterior brachii, facies brachialis anterior.
anterior brachial r. the anterior r. of the arm.
anterior carpal r. SYN: anterior r. of wrist.
anterior cervical r. [TA] the area of the neck bounded by the mandible, the anterior border of the sternocleidomastoid muscle, and the anterior midline of the neck; it is subdivided into carotid, muscular, submandibular, and submental triangles. SYN: regio cervicalis anterior [TA] , anterior triangle of neck&star, trigonum cervicale anterius&star, trigonum colli anterius&star, anterior r. of neck.
anterior crural r. SYN: anterior r. of leg.
anterior cubital r. SYN: anterior r. of elbow.
anterior r. of elbow [TA] the area in front of the elbow, including the cubital fossa. SYN: regio cubitalis anterior [TA] , anterior cubital r., anterior surface of elbow, facies cubitalis anterior.
anterior r. of forearm [TA] the area between the radial and ulnar borders of the forearm anteriorly. SYN: regio antebrachii anterior [TA] , regio antebrachialis anterior&star, anterior antebrachial r., anterior surface of forearm, facies antebrachialis anterior, facies anterior antebrachii.
anterior hypothalamic r. anterior hypothalamic area.
anterior knee r. SYN: anterior r. of knee.
anterior r. of knee [TA] the anterior r. of the knee. SYN: regio genus anterior [TA] , anterior knee r..
anterior and lateral thoracic regions [TA] the topographic divisions of the chest: presternal, pectoral, and axillary. SYN: regiones thoracicae anteriores et laterales [TA] , regions of chest.
anterior r. of leg [TA] the anterior surface of the inferior limb between the knee and the ankle. SYN: regio cruris anterior [TA] , anterior crural r., anterior surface of leg, facies anterior cruris, facies cruralis anterior.
anterior r. of neck SYN: anterior cervical r..
anterior r. of thigh [TA] the front of the thigh, including the femoral triangle. SYN: regio femoris anterior [TA] , anterior surface of thigh, facies femoralis anterior.
anterior r. of wrist [TA] the anterior part of the wrist. SYN: regio carpalis anterior [TA] , anterior carpal r..
axillary r. [TA] the r. of the axilla, including the axillary fossa. SYN: regio axillaris [TA] .
regions of back [TA] the topographic regions of the back of the trunk, including the vertebral r., sacral r., scapular r., infrascapular r., and lumbar r.. SYN: regiones dorsales [TA] , regiones dorsi&star.
regions of body the topographic divisions of the body. SYN: regiones corporis.
buccal r. [TA] the r. of the cheek, corresponding approximately to the outlines of the underlying buccinator muscle. SYN: regio buccalis [TA] .
calcaneal r. SYN: heel r..
regions of chest SYN: anterior and lateral thoracic regions.
chromosomal r. that part of a chromosome defined either by anatomical details, notably banding, or by its linkages (linkage group).
complementarity determining regions that part of an antibody or T cell receptor variable r. that binds with antigen or antigen/major histocompatibility molecule.
constant r. immunoglobulin.
deltoid r. [TA] the lateral aspect of the shoulder demarcated by the outlines of the deltoid muscle. SYN: regio deltoidea [TA] .
dorsal hypothalamic r. dorsal hypothalamic area.
epigastric r. [TA] the r. of the abdomen located between the costal margins and the subcostal plane. (TA lists this term as synonymous with epigastric fossa. SYN: epigastrium [TA] , regio epigastrica&star.
regions of face SYN: face r..
face r. [TA] the topographic subdivisions of the face, including nasal, oral, mental, orbital, infraorbital, buccal, parotid, and zygomatic. SYN: regio facialis [TA] , regions of face.
femoral r. [TA] the r. of the thigh between hip and knee. SYN: regio femoris [TA] .
framework r. in immunology, a conserved sequence of amino acids on either side of the hypervariable regions in the variable domains of an immunoglobulin chain.
frontal r. of head [TA] the surface r. of the head corresponding to the outlines of the frontal bone. SYN: regio frontalis capitis [TA] .
gluteal r. [TA] the r. of the buttocks. SYN: regio glutealis [TA] .
regions of head [TA] the topographic division of the cranium in relation to the bones of the cranial vault; the regions include frontal, parietal, occipital, temporal, auricular, mastoid, and facial. SYN: regiones capitis [TA] .
heel r. [TA] the r. of the heel. SYN: regio calcanea [TA] , calcaneal r..
hinge r. 1. that part of a tRNA structure that is deformed, bending a “cloverleaf” (two-dimensional) model to form an “L” model (crystal form, as seen by electron microscopy); 2. in an immunoglobulin, a short sequence of amino acids that lies between two longer sequences and allows the latter to bend about the former.
hypervariable regions (hi-per′var-i-a-ble) the regions of the immunoglobulin molecule that contain most of the residues involved in the antibody binding site.
hypochondriac r. the r. on each side of the abdomen covered by the costal cartilages; it is lateral to the epigastric r.. SYN: hypochondrium [TA] , regio hypochondriaca&star.
I r. that area of the H-2 complex of mice that contains Class II major histocompatibility complex genes.
iliac r. SYN: groin (1) .
regions of inferior limb SYN: regions of lower limb.
inframammary r. [TA] the r. of the chest (portion of pectoral r.) inferior to the mammary gland. SYN: regio inframammaria [TA] .
infraorbital r. [TA] the facial r. below the orbit and lateral to the nose on each side. SYN: regio infraorbitalis [TA] .
infrascapular r. [TA] the r. of the back lateral to the vertebral r. and below the scapula. SYN: regio infrascapularis [TA] .
inguinal r. groin (1) .
r. of interest in computed tomography or other computerized imaging, an interactively selected portion of the image, the individual or average pixel values of which can be displayed numerically.
intermediate r. [TA] SYN: intermediate column.
intermediate hypothalamic r. intermediate hypothalamic area.
K r. carbons 9 and 10 of the phenanthrene ring system; thought by some to be the reactive spot in the various hydrocarbon carcinogens.
lateral abdominal r. flank.
lateral r. of abdominal r. flank.
lateral cervical r. [TA] the r. of the neck bounded by the sternocleidomastoid muscle, the trapezius muscle, and the upper border of the clavicle, including the omoclavicular triangle. SYN: regio cervicalis lateralis [TA] , posterior triangle of neck&star, trigonum cervicale posterius&star, trigonum colli laterale&star, lateral r. of neck.
lateral hypothalamic r. extends throughout most of the rostrocaudal extent of the hypothalamus lateral to the column of the fornix; includes lateral tuberal nuclei, tuberomamillary nuclei, and diffuse populations of cells.
lateral r. of neck SYN: lateral cervical r..
regions of lower limb [TA] the topographic divisions of the lower limb: gluteal, hip, femoral, knee, leg, ankle, and foot. SYN: regiones membri inferioris [TA] , regions of inferior limb.
lumbar r. [TA] the r. of the back lateral to the vertebral r. and between the rib cage and the pelvis. SYN: regio lumbalis [TA] .
mammary r. [TA] the r. of the chest (pectoral r.) that includes the breast. SYN: regio mammaria [TA] .
mental r. [TA] the r. of the chin. SYN: regio mentalis [TA] .
nasal r. [TA] the r. of the nose. SYN: regio nasalis [TA] .
regions of neck [TA] the topographic subdivisions of the neck. SYN: regiones cervicales [TA] .
nuchal r. SYN: posterior cervical r..
nucleolus organizer r. an arrangement of the DNA coding for the production of ribosomal RNA (rRNA).
occipital r. of head [TA] the surface r. of the head corresponding to the outlines of the occipital bone. SYN: regio occipitalis capitis [TA] .
r. of olfactory mucosa SYN: olfactory r. of nasal mucosa.
olfactory r. of mucosa of nose [TA] epithelium containing nerve cells whose axons form the filaments of the olfactory nerve; the lamina propria contains numerous olfactory glands (Bowman) that open to the surface. SYN: olfactory mucosa.
olfactory r. of nasal mucosa [TA] the specialized olfactory receptive area that includes the upper one-third of the nasal septum and the lateral wall above the superior concha; it is lined with olfactory mucosa. SYN: pars olfactoria tunicae mucosae [TA] , olfactory r. of tunica mucosa of nose, regio olfactoria tunicae mucosae nasi, r. of olfactory mucosa, Schultze membrane.
olfactory r. of nose [TA] that part of the nasal mucosa having olfactory receptor cells and glands of Bowman. SYN: olfactory membrane.
olfactory r. of tunica mucosa of nose SYN: olfactory r. of nasal mucosa.
oral r. [TA] the r. of the face including the lips and mouth. SYN: regio oralis [TA] .
orbital r. [TA] the r. about the orbit. SYN: regio orbitalis [TA] .
parietal r. [TA] the surface r. of the head corresponding to the outlines of the underlying parietal bone. SYN: regio parietalis capitis [TA] .
pectoral r. [TA] the r. of the chest demarcated by the outline of the pectoralis major muscle; includes lateral pectoral, mammillary, and inframammary regions. SEE ALSO: anterior and lateral thoracic regions. SYN: regio pectoralis [TA] .
perineal r. [TA] the regio at the lower end of the trunk, anterior to the sacral r. and posterior to the pubic r. between the thighs; it is divided into the anal triangle posteriorly and the urogenital triangle anteriorly. SYN: regio perinealis [TA] .
plantar r. sole of foot.
popliteal r. SYN: popliteal fossa.
posterior antebrachial r. SYN: posterior r. of forearm.
posterior r. of arm [TA] the back of arm. SYN: regio antebrachii posterior [TA] , regio brachialis posterior&star, facies brachialis posterior, posterior brachial r., posterior surface of arm.
posterior brachial r. SYN: posterior r. of arm.
posterior carpal r. SYN: posterior r. of wrist.
posterior cervical r. [TA] the back of neck, including the suboccipital r.. SYN: regio cervicalis posterior [TA] , regio colli posterior&star, nuchal r., posterior neck r., posterior r. of neck, regio nuchalis.
posterior crural r. SYN: posterior r. of leg.
posterior cubital r. SYN: posterior r. of elbow.
posterior r. of elbow [TA] the back of the elbow. SYN: regio cubitalis posterior&star, facies cubitalis posterior, posterior cubital r., posterior surface of elbow.
posterior r. of forearm [TA] the area between the radial and ulnar borders of the forearm posteriorly. SYN: regio antebrachialis posterior&star, facies antebrachialis posterior, posterior antebrachial r., posterior surface of forearm.
posterior hypothalamic r. caudal portions of the hypothalamus located internally in the area of the mamillary body, includes medial, intermediate, and lateral mamillary nuclei and the posterior hypothalamic nuclei. SEE ALSO: posterior hypothalamic area.
posterior knee r. SYN: posterior r. of knee.
posterior r. of knee [TA] the posterior r. of the knee, including the popliteal fossa. SYN: regio genus posterior [TA] , posterior knee r..
posterior r. of leg [TA] the back of the leg. SYN: regio cruralis posterior [TA] , facies cruralis posterior, facies posterior cruris, posterior crural r., posterior surface of leg.
posterior r. of neck SYN: posterior cervical r..
posterior neck r. SYN: posterior cervical r..
posterior r. of thigh [TA] the back of the thigh. SYN: regio femoris posterior [TA] , facies femoralis posterior, posterior surface of thigh, regio femoralis posterior.
posterior r. of wrist [TA] the posterior part of the wrist. SYN: regio carpalis posterior [TA] , posterior carpal r..
preoptic r. the most anterior part of the hypothalamus surrounding the anterior or preoptic part of the third ventricle and including the lamina terminalis; containing the lateral and medial preoptic nucleus continuous caudally with, respectively, the lateral and anterior hypothalamic nucleus; rostrally the preoptic r. is continuous with the precommissural septum, laterally with the innominate substance. SYN: area preoptica [TA] , preoptic area [TA] .
presternal r. [TA] the part of the chest over the sternum. SYN: regio presternalis [TA] .
presumptive r. in experimental embryology, an area of the blastula from which a specific tissue or organ may be expected to develop.
pretectal r. SYN: pretectal area.
pubic r. [TA] the lower central r. of the abdomen below the umbilical r. and superior to the mons pubis. SYN: hypogastrium [TA] , regio pubica&star.
r. of respiratory mucosa SYN: respiratory r. of mucosa of nasal cavity.
respiratory r. of mucosa of nasal cavity [TA] the area commencing at the vestibule of the nose lined with respiratory mucosa; with the exception of the olfactory mucusa, it includes the entire nasal cavity. SYN: pars respiratoria tunicae mucosae [TA] , regio respiratoria tunicae mucosae nasi, r. of respiratory mucosa, respiratory r. of tunica mucosa of nose.
respiratory r. of tunica mucosa of nose SYN: respiratory r. of mucosa of nasal cavity.
sacral r. [TA] the area of the back overlying the sacrum. SYN: regio sacralis [TA] .
scaffold-associated regions (SAR) sites in DNA that bind topoisomerase II and other scaffold proteins; found in introns.
scapular r. [TA] the area of the back corresponding to the outlines of the scapula. SYN: regio scapularis [TA] .
sternocleidomastoid r. [TA] the r. overlying the sternocleidomastoid muscle, including the lesser supraclavicular fossa. SYN: regio sternocleidomastoidea [TA] .
suboccipital r. upper back of neck, inferior to occipital r. of head and above the level of the second cervical vertebra; overlies (or includes, deeply) the suboccipital triangle.
regions of superior limb SYN: regions of upper limb.
sural r. [TA] the muscular swelling of the back of the leg below the knee, formed chiefly by the bellies of the gastrocnemius and soleus muscles. SYN: regio suralis [TA] .
temporal r. of head [TA] the surface r. of the head corresponding approximately to the outlines of the temporal bone. SYN: regio temporalis capitis [TA] .
umbilical r. [TA] the central r. of the abdomen about the umbilicus. SYN: regio umbilicalis [TA] .
regions of upper limb [TA] the topographic divisions of the upper limb: deltoid, arm, brachial, cubital, antebrachial, carpal, and hand. SYN: regiones membri superioris [TA] , regions of superior limb.
urogenital r. SYN: urogenital triangle.
variable r. immunoglobulin.
vertebral r. [TA] the central r. of the back, corresponding to the underlying vertebral column. SYN: regio vertebralis [TA] .
Wernicke r. SYN: Wernicke center.
zygomatic r. [TA] the r. of the face outlined by the zygomatic bone; the prominence above the cheek. SYN: regio zygomatica [TA] .

regional
regional (re′jun-al)

Relating to a region.

regiones
regiones (re′je-o′nez)

Plural of regio. [L.]

The file of data concerning all cases of a specified condition, such as cancer, occurring in a defined population; the r. is the actual document, and the registry is the system of ongoing registration. [Mediev. L. registrum, fr. L.L. regero, pp. regestum to record]

registration
registration (rej-is-tra′shun)

In dentistry, a record.
maxillomandibular r. SYN: maxillomandibular record.
tissue r. in dentistry, 1. the accurate r. of the shape of tissues under any condition by means of a suitable material; 2. an impression.

registry
registry (rej′is-tre)

1. An organization that lists professionals in certain fields. 2. An agency for the collection of pathologic material and related information and the organization of these materials for the purpose of study. 3. An agency for the collection of data on individuals who have had a certain disease to allow follow-up and evaluation of response to therapy.

regnancy
regnancy (reg′nan-se)

The briefest unit of experience; the unit composed of the total physiologic processes occurring at a single moment, which constitute dominant configurations in the brain. A single process constituting part of the r. is referred to as a regnant process. [L. regnant-, regnans, pres. p. of regno, to rule]

regression
regression (re-gresh′un)

1. A subsidence of symptoms. 2. A relapse; a return of symptoms. 3. Any retrograde movement or action. 4. A return to a more primitive mode of behavior due to an inability to function adequately at a more adult level. 5. The tendency for offspring of exceptional parents to possess characteristics closer to those of the general population. 6. An unconscious defense mechanism by which there occurs a return to earlier patterns of adaptation. 7. The distribution of one random variable given particular values of other variables relevant to it, e.g., a formula for the distribution of weight as a function of height and chest circumference. The method was formulated by Galton in his study of quantitative genetics. [L. regredior, pp. -gressus, to go back]
phonemic r. a decrease in intelligibility of speech associated with aging.

regressive
regressive (re-gres′iv)

Relating to or characterized by regression.

regulation
regulation (reg′u-la′shun)

1. Control of the rate or manner in which a process progresses or a product is formed. 2. In experimental embryology, the power of a pregastrula embryo to continue approximately normal development after a part or parts have been manipulated or destroyed. [L. regula, a rule]
enzyme r. control of the rate of a reaction catalyzed by an enzyme by some effector ( E.G., inhibitors or activators) or by alteration of some condition ( E.G., pH or ionic strength).
gene r. control of protein synthesis by means of activation or inhibition of that protein synthesis.

regulator
regulator (reg-u-la′tor)

A substance or process that controls another substance or process.
growth regulators substances that can alter the growth of a living organism.
humoral r. a substance whose action is a result of contact with targets for activity through blood or body fluids.

regulon
regulon (reg′u-lon)

A set of structural genes, all with the same gene regulation, whose gene products are involved in the same reaction pathway.

regurgitant
regurgitant (re-ger′ji-tant)

Regurgitating; flowing backward.

regurgitate
regurgitate ( re-ger′ji-tat)

1. To flow backward. 2. To expel the contents of the stomach in small amounts, short of vomiting. [L. re-, back, + gurgito, pp. -atus, to flood, fr. gurges (gurgit-), a whirlpool]

regurgitation
regurgitation (re-ger′ji-ta′shun)

1. A backward flow, as of blood through an incompetent valve of the heart. 2. The return of gas or small amounts of food from the stomach. [L. regurgitatio (see regurgitate)]
aortic r. reflux of blood through an incompetent aortic valve into the left ventricle during ventricular diastole. SYN: Corrigan disease.
ischemic mitral r. a r. of the mitral valve caused by ischemic heart disease.
mitral r. reflux of blood through an incompetent mitral valve.
pulmonic r. incompetence of the pulmonic valve permitting retrograde flow.
valvular r. a leaky state of one or more of the cardiac valves, the valve not closing tightly and blood therefore regurgitating through it. SYN: valvular incompetence, valvular insufficiency.

rehabilitation
rehabilitation (re′ha-bil-i-ta′shun)

Restoration, following disease, illness, or injury, of the ability to function in a normal or near-normal manner. [L. rehabilitare, pp. -tatus, to make fit, fr. re- + habilitas, ability]
mouth r. restoration of the form and function of the masticatory apparatus to as nearly a normal condition as possible.

rehearsal
rehearsal (re-her′sal)

A process associated with enhancing short-term and long-term memory wherein newly presented information, such as a name or a list of words, is repeated to oneself one or more times in order not to forget it.

Rehfuss
Rehfuss

Martin E., U.S. physician, 1887–1964. See R. method, R. stomach tube.

rehydration
rehydration (re-hi-dra′shun)

The return of water to a system after its loss.

Reichel
Reichel

Friedrich P., German gynecologist and surgeon, 1858–1934. See R.-Pólya stomach procedure.

Reichert
Reichert

Karl B., German anatomist, 1811–1883. See R. cartilage, R. cochlear recess, R.-Meissl number.

Reid
Reid

Robert W., Scottish anatomist, 1851–1939. See R. base line.

Reifenstein
Reifenstein

Edward C. Jr., U.S. endocrinologist, 1908–1975. See R. syndrome.

Reil
Reil

Johann C., German physician, neurologist, and histologist, 1759–1813. See R. ansa, R. band, R. ribbon, R. triangle, limiting sulcus of R., circular sulcus of R., island of R..

reimplantation
reimplantation (re′im-plan-ta′shun)

SYN: replantation.
extravesical r. SYN: detrusorrhaphy.
ureteral r. SYN: ureteroneocystostomy.

reinfection
reinfection (re-in-fek′shun)

A second infection by the same microorganism, after recovery from or during the course of a primary infection.

reinforcement
reinforcement (re-in-fors′ment)

1. An increase of force or strength; denoting specifically the increased sharpness of the patellar reflex when the patient at the same time closes the fist tightly or pulls against the flexed fingers or contracts some other set of muscles. SEE ALSO: Jendrassik maneuver. 2. In dentistry, a structural addition or inclusion used to give additional strength in function; e.g., bars in plastic denture base. 3. In conditioning, the totality of the process in which the conditioned stimulus is followed by presentation of the unconditioned stimulus, which itself elicits the response to be conditioned. SEE ALSO: reinforcer, schedules of r., under schedule, classical conditioning, operant conditioning.
primary r. satisfaction of physiologic needs or drives, such as that supplied by food or sleep.
secondary r. r. through something which, while it does not satisfy the need directly, has been associated with direct satisfaction of the need, such as the effect on behavior of a food or beer commercial on television.

reinforcer
reinforcer (re-in-fors′er)

In conditioning, a pleasant or satisfaction-yielding (positive r.) or painful or unsatisfying (negative r.), stimulus, object, or stimulus event that is obtained upon the performance of a desired or predetermined operant. SEE ALSO: reinforcement (3) . SYN: reward.

Reinke
Reinke

Friedrich B., German anatomist, 1862–1919. See R. crystalloids, under crystalloid.

reinnervation
reinnervation (re-in-ner-va′shun)

Restoration of nerve control of a paralyzed muscle or other effector organ by means of regrowth of nerve fibers, either spontaneously or after anastomosis.

reinoculation
reinoculation (re′i-nok-u-la′shun)

Reinfection by means of inoculation.

Reinsch
Reinsch

Adolf, German physician, 1862–1916. See R. test.

reintegration
reintegration (re′in-te-gra′shun)

In the mental health professions, the return to well-adjusted functioning following disturbances due to mental illness.

reinversion
reinversion (re-in-ver′shun)

The correction, spontaneous or operative, of an inversion, as of the uterus.

Reis
Reis

Heinrich Maria Wilhelm, German ophthalmologist, *1872. See R.-Bücklers corneal dystrophy. SEE ALSO: R.-Bücklers corneal dystrophy.

Reisseisen
Reisseisen

Franz D., German anatomist, 1773–1828. See R. muscles, under muscle.

Reissner
Reissner

Ernst, German anatomist, 1824–1878. See R. fiber, R. membrane.

Reitan
Reitan

Ralph M., U.S. psychologist, *1922. See Halstead-R. battery.

Reiter
Reiter

Hans, German bacteriologist, 1881–1969. See R. test, R. disease, R. syndrome, Fiessinger-Leroy-R. syndrome.

rejection
rejection (re-jek′shun)

1. The immunologic response to incompatibility in a transplanted organ. 2. A refusal to accept, recognize, or grant; a denial. 3. Elimination of small ultrasonic echoes from display. [L. rejectio, a throwing back]
accelerated r. a transplant r. manifested in less than 3 days.
acute r. SYN: acute cellular r..
acute cellular r. graft r. that usually begins within 10 days after a graft has been transplanted into a genetically dissimilar host. Lesions at the site of the graft characteristically are infiltrated with large numbers of lymphocytes and macrophages that cause tissue damage. See primary r.. SYN: acute r..
allograft r. (al′lo-graft) the r. of tissue transplanted between two genetically different individuals of the same species. R. is caused by T lymphocytes responding to the foreign major histocompatibility complex of the graft.
chronic r. a transplant r. occurring gradually, sometimes months later.
chronic allograft r. immunologically mediated damage to the allograft, typically occurring months or years after transplantation.
first-set r. allograft transplantation between two organisms not previously sensitized to the graft tissue. Necrosis of the graft usually begins within 10 days of transplantation.
hyperacute r. 1. a r. that usually develops immediately after the implantation of a vascular graft; may be caused by preformed, cytotoxic antibodies to the graft; 2. a form of antibody-mediated, usually irreversible damage to a transplanted organ, particularly the kidney, manifested predominantly by diffuse thrombotic lesions, usually confined to the organ itself and only rarely disseminated.
parental r. 1. withholding of affection from or denial of attention to one's child; 2. child's withholding of affection from its parent.
primary r. a r. occurring more than 7 days after transplantation, mainly from a cellular immune response.
second set r. an accelerated r. of a transplant that occurs when an individual has been previously sensitized to the graft.

rejuvenescence
rejuvenescence (re-joo-ve-nes′ens)

A renewal of youth; return of a cell or tissue to a state in which it was in an earlier stage of existence. [L. re-, again, + juvenesco, to grow young, fr. juvenis, a youth]

relapse
relapse (re′laps)

Return of the manifestations of a disease after an interval of improvement. SYN: recurrence (2) . [L. re-labor, pp. -lapsus, to slide back]

relapsing
relapsing (re-lap′sing)

Recurring; said of a disease or its manifestations that returns in a new attack after an interval of improvement.

relation
relation (re-la′shun)

1. An association or connection between or among people or objects. SEE ALSO: relationship. 2. In dentistry, the mode of contact of teeth or the positional relationship of oral structures. [L. relatio, a bringing back]
acquired centric r. centric jaw r..
acquired eccentric r. an eccentric r. that is assumed by habit in order to bring the teeth into occlusion.
buccolingual r. the position of a space or tooth in r. to the tongue and the cheek.
centric jaw r., centric r. 1. the most retruded physiologic r. of the mandible to the maxillae to and from which the individual can make lateral movements; it is a condition that can exist at various degrees of jaw separation, and it occurs around the terminal hinge axis; 2. the most posterior r. of the mandible to the maxillae at the established vertical r. SEE ALSO: eccentric r.. SYN: median retruded r., median r..
dynamic relations relative movements between two objects, e.g., the relationship of the mandible to the maxillae.
eccentric r. any r. of the mandible to the maxillae other than centric r.. SYN: eccentric position.
intermaxillary r. SYN: maxillomandibular r..
maxillomandibular r. any one of the many relations of the mandible to the maxillae, e.g., centric jaw r., eccentric r.. SYN: intermaxillary r..
median retruded r., median r. SYN: centric jaw r..
occluding r. the jaw r. at which the opposing teeth occlude.
protrusive r. the r. of the mandible to the maxillae when the lower jaw is thrust forward.
protrusive jaw r. a jaw r. resulting from a protrusion of the mandible.
rest r. the postural r. of the mandible to the maxillae when the patient is resting comfortably in the upright position and the condyles are in a neutral unstrained position in the glenoid fossa. SYN: rest jaw r., unstrained jaw r..
rest jaw r. SYN: rest r..
ridge r. the positional r. of the mandibular ridge to the maxillary ridge.
static r. relationship between two parts that are not in motion.
unstrained jaw r. SYN: rest r..

relationship
relationship (re-la′shun-ship)

The state of being related, associated, or connected.
dose-response r. r. in which a change in the amount, intensity, or duration of exposure is associated with a change in risk of a specified outcome.
dual relationships relationships in which a health service provider is concurrently participating in two or more role categories with a patient; such dual relationships may be benign (as when both are members of the same social group) or exploitive (a sexual r.).
Haldane r. a mathematical r. between the equilibrium constant of an enzyme-catalyzed reaction and all of that enzyme's kinetic parameters ( e.g., V_max and K_m's).
hypnotic r. r. between hypnotist and the hypnotized.
object r. in the behavioral sciences, the emotional bond between an individual and another person (or between two groups), as opposed to the individual's (or group's) interest in him or herself (itself).
sadomasochistic r. a r. characterized by the complementary enjoyment of inflicting and suffering cruelty.

relax
relax (re-laks′)

1. To loosen; to slacken. 2. To cause a movement of the bowels. [L. re-laxo, to loosen]

relaxant
relaxant (re-lak′sant)

1. Relaxing; causing relaxation; reducing tension, especially muscular tension. 2. An agent that reduces muscular tension or produces skeletal muscle paralysis, usually referred to as a muscle r..
depolarizing r. an agent, e.g., succinylcholine, that induces depolarization of the motor endplate and so paralyzes skeletal muscle by a phase I block.
muscle r. a drug with the capacity to reduce muscle tone; may be either a peripherally acting muscle r. such as curare and act to produce blockade at the neuromuscular junction (and thus useful in surgery), or act as a centrally acting muscle r. exerting its effects within the brain and spinal cord to diminish muscle tone (and thus useful in muscle spasm or spasticity).
neuromuscular r. an agent, e.g., curare or succinylcholine, that produces relaxation of striated muscle by interruption of transmission of nervous impulses at the myoneural junction.
nondepolarizing r. an agent, e.g., tubocurarine, that paralyzes skeletal muscle without depolarization of the motor endplate, as in phase II block.
smooth muscle r. an agent, such as an antispasmodic, bronchodilator, or vasodilator, that reduces the tension or tone of smooth (involuntary) muscle.

relaxation
relaxation (re-lak-sa′shun)

1. Loosening, lengthening, or lessening of tension in a muscle. 2. In nuclear magnetic resonance, r. is the decay in magnetization of protons after the direction of the surrounding magnetic field is changed; the different rates of r. for individual nuclei and tissues are used to provide contrast in imaging. [L. relaxatio (see relax)]
cardioesophageal r. r. of the lower esophageal sphincter, which can allow reflux of acidic gastric contents into the lower esophagus, producing esophagitis.
isometric r. decrease in tension of a muscle while the length remains constant because of fixation of the ends.
isovolumetric r. SYN: isovolumic r..
isovolumic r. that part of the cardiac cycle between the time of aortic valve closure and mitral opening, during which the ventricular muscle decreases its tension without lengthening so that ventricular volume remains unaltered; the heart is never precisely isovolumetric (vs. isovolumic) except during long diastoles with a midiastolic period of diastasis. SYN: isovolumetric r..
longitudinal r. in nuclear magnetic resonance, the return of the magnetic dipoles of the hydrogen nuclei (magnetization vector) to equilibrium parallel to the magnetic field, after they have been flipped 90°; varies in rate in different tissues, taking up to 15 s for water. See TI. SYN: spin-lattice r., spin-spin r..
spin-lattice r. SYN: longitudinal r..
spin-spin r. SYN: longitudinal r..
transverse r. in nuclear magnetic resonance, the decay of the nuclear magnetization vector at right angles to the magnetic field after the 90° pulse is turned off; the signal is called free induction decay. See T2. Cf.:longitudinal r..

relaxin
relaxin (re-lak′sin)

A polypeptide hormone secreted by the corpora lutea of mammalian species during pregnancy. Facilitates the birth process by causing a softening and lengthening of the pubic symphysis and cervix; it also inhibits contraction of the uterus and may play a role in timing of parturition. SYN: cervilaxin, ovarian hormone, releasin. [relax + -in]

relearning
relearning (re-lern′ing)

The process of regaining a skill or ability that has been partially or entirely lost; savings involved in r., as compared with original learning, give an index of the degree of retention.

releasin
releasin

SYN: relaxin.

reliability
reliability (re-li-a-bil′i-te)

The degree of stability exhibited when a measurement is repeated under identical conditions. See correlation coefficient, r. coefficient. [M.E. relien, fr. O.Fr. relier, fr. L. religo, to bind]
equivalent form r. in psychology, the consistency of measurement based on the correlation between scores on two similar forms of the same test taken by the same individual. SEE ALSO: r. coefficient.
interjudge r. in psychology, the consistency of measurement obtained when different judges or examiners independently administer the same test to the same individual. SYN: interrater r..
interrater r. SYN: interjudge r..
test-retest r. in psychology, the consistency of measurement based on the correlation between test and retest scores for the same individual. SEE ALSO: coefficient, r..

relief
relief (re-lef′)

1. Removal of pain or distress, physical or mental. 2. In dentistry, reduction or elimination of pressure from a specific area under a denture base. SEE ALSO: r. area, r. chamber. [see relieve]

relieve
relieve (re-lev′)

To free wholly or partly from pain or discomfort, either physical or mental. [through O. Fr. fr. L. re-levo, to lift up, lighten]

reline
reline (re′lin′)

In dentistry, to resurface the tissue side of a denture with new base material to make it fit more accurately. SEE ALSO: rebase.

REM
REM

1. Acronym for rapid eye movements, under movement. 2. Acronym for reticular erythematous mucinosis. See R. syndrome.

rem
rem

Abbreviation for roentgen-equivalent-man.

Remak
Remak

Ernst J., German neurologist, 1848–1911. See R. reflex, R. sign.

Remak
Remak

Robert, Polish-German anatomist and histologist, 1815–1865. See R. nuclear division, R. fibers, under fiber, R. ganglia, under ganglion, R. plexus.

remediable
remediable (re-me′de-a-bl)

Curable. [L. remediabilis, fr. remedio, to cure]

remedial
remedial (re-me′de-al)

Curative or acting as a remedy.

remedy
remedy (rem′e-de)

An agent that cures disease or alleviates its symptoms. [L. remedium, fr. re-, again, + medeor, cure]

remineralization
remineralization (re′min′er-al-i-za′shun)

1. The return to the body or a local area of necessary mineral constituents lost through disease or dietary deficiencies; commonly used in referring to the content of calcium salts in bone. 2. In dentistry, a process enhanced by the presence of fluoride whereby partially decalcified enamel, dentin, and cementum become recalcified by mineral replacement.

reminiscence
reminiscence (rem-i-nis′sens)

In the psychology of learning, an improvement in recall, over that shown on the last trial, of incompletely learned material after an interval without practice. [L. reminiscentiae, from reminiscor, to remember]

remission
remission (re-mish′un)

1. Abatement or lessening in severity of the symptoms of a disease. 2. The period during which such abatement occurs. [L. remissio, fr. re-mitto, pp. -missus, to send back, slacken, relax]
spontaneous r. disappearance of symptoms without formal treatment.

remit
remit (re-mit′)

To become less severe for a time without absolutely ceasing. [see remission]

remittence
remittence (re-mit′ens)

A temporary amelioration, without actual cessation, of symptoms.

remittent
remittent (re-mit′ent)

Characterized by temporary periods of abatement of the symptoms of a disease.

remnant
remnant (rem′nant)

Something remaining, a residue or vestige. [O. Fr., fr. remaindre, to remain, fr. L. remaneo]

remodeling
remodeling (re-mod′el-ing)

1. A cyclic process by which bone maintains a dynamic steady state through sequential resorption and formation of a small amount of bone at the same site; unlike the process of modeling, the size and shape of remodeled bone remain unchanged. 2. Any process of reshaping or reorganizing.
heart chamber r. an architectural change in any cardiac chamber (usually one or both ventricles) due to a pathologic or normal (neonatal) stimulus.

ren
ren, gen. renis, pl .renes (ren, re′nis, re′nez)

SYN: kidney. [L.]

renal
renal (re′nal)

SYN: nephric.

renaturation
renaturation (re-na-tu-ra′shun)

The conversion of a denatured and inactive macromolecule back to its natured and bioactive configuration.

renculus
renculus (ren′koo-lus)

1. SYN: cortical lobules of kidney, under lobule. 2. SYN: reniculus (2) .

Rendu
Rendu

Henri J.L.M., French physician, 1844–1902. See R.-Osler-Weber syndrome.

reni- reni-

See reno-.

renicapsule
renicapsule (ren′i-kap′sool)

The capsule of the kidney. [reni- + L. capsula, capsule]

renicardiac
renicardiac (ren′i-kar′de-ak)

SYN: cardiorenal. [reni- + G. kardia, heart]

reniculus
reniculus, pl .reniculi (re-nik′u-lus, -li)

1. SYN: cortical lobules of kidney, under lobule. 2. A lobe of the human fetal kidney and that of some lower animals in which fibrous septa subdivide the organ. SYN: renculus (2) , renunculus (2) . [L. dim. of ren, kidney]

reniform
reniform (ren′i-form)

SYN: nephroid.

renin
renin (re′nin)

A term originally used for a pressor substance obtained from rabbits' kidneys, now an enzyme that converts angiotensinogen to angiotensin I. SYN: angiotensinogenase.

reniportal
reniportal (ren′i-por′tal)

1. Relating to the hilum of the kidney. 2. Relating to the portal, or venous capillary circulation in the kidney. [reni- + L. porta, gate]

rennase
rennase (ren′as)

SYN: chymosin.

rennet
rennet (ren′et)

SYN: chymosin.

rennin
rennin (ren′in)

SYN: chymosin.

renninogen
renninogen, rennogen (re-nin′o-jen, ren′o-jen)

SYN: prochymosin. [rennin + G. -gen, producing]

reno- reno-, reni-

The kidney. SEE ALSO: nephro-. [L. ren]

renocutaneous
renocutaneous (re′no-ku-ta′ne-us)

Relating to the kidneys and the skin. [reno- + L. cutis, skin]

renogastric
renogastric (re′no-gas′trik)

Relating to the kidneys and the stomach. [reno- + G. gaster, stomach]

renogenic
renogenic (re-no-jen′ik)

Originating in or from the kidney.

renogram
renogram (re′no-gram)

The assessment of renal function by external radiation detectors after the administration of a radiopharmaceutical that is filtered and excreted by the kidney. [reno- + G. gramma, something written]

renography
renography (re-nog′ra-fe)

Radiography of the kidney.

renointestinal
renointestinal (re′no-in-tes′ti-nal)

Relating to the kidneys and the intestine.

renomegaly
renomegaly (re′no-meg′a-le)

Enlargement of the kidney.

renopathy
renopathy (re-nop′a-the)

A rarely used term for nephropathy.

renoprival
renoprival (re-no-pri′val)

Relating to, characterized by, or resulting from total loss of kidney function or from removal of all functioning renal tissue. [reno- + L. privus, deprived of]

renopulmonary
renopulmonary (re′no-pul′mo-nar-e)

Relating to the kidneys and the lungs.

renotrophic
renotrophic (re-no-trof′ik)

Relating to any agent influencing the growth or nutrition of the kidney or to the action of such an agent. SYN: nephrotrophic, nephrotropic, renotropic. [reno- + G. trophe, nourishment]

renotrophin
renotrophin (re-no-tro′fin)

An agent affecting the growth or nutrition of the kidney. SYN: renotropin.

renotropic
renotropic (re-no-trop′ik)

SYN: renotrophic. [reno- + G. trope, a turning]

renotropin
renotropin (re-no-tro′pin)

SYN: renotrophin.

renovascular
renovascular (re-no-vas′ku-ler)

Pertaining to the blood vessels of the kidney, denoting especially disease of these vessels.

Renpenning
Renpenning

H., 20th century Canadian physician. See R. syndrome.

ren. sem.
ren. sem.

Abbreviation for [L.] renovetur semel, shall be renewed (only) once.

Renshaw
Renshaw

B., 20th century U.S. neurophysiologist. See R. cells, under cell.

renunculus
renunculus (re-nung′ku-lus)

1. SYN: cortical lobules of kidney, under lobule. 2. SYN: reniculus (2) . [L. dim. of ren]

Reoviridae
Reoviridae (re-o-vir′i-de)

A family of double-stranded RNA viruses, some of which (Reovirus) previously were included with ECHO viruses, and others (Orbivirus), with arboviruses. Virions are 60–80 nm in diameter, usually naked, and ether-resistant; genomes contain double-stranded, segmented RNA (MW 10–16 × 10⁶); capsids are of icosohedral symmetry with two layers of capsomeres. The family comprises nine genera: Orthoreovirus, Orbivirus, Rotavirus, Coltivirus, Aquareovirus, cytoplasmic polyhedrosis virus group (Cypovirus), and three plant reovirus groups (Phytoreovirus, Fijivirus, and Oryzavirus). [Respiratory Enteric Orphan + viridae]

Reovirus
Reovirus (re′o-vi′rus)

A genus of viruses currently called Orthoreovirus (family Reoviridae) that are 80 nm in diameter, with distinct double layers of capsomeres, and have vertebrates as hosts; they have been recovered from children with upper respiratory tract infections, mild fever, and sometimes diarrhea, and from children with no apparent infection; from chimpanzees with coryza; monkeys and mice; and cattle feces. There are three antigenically distinct human types related by a common complement-fixing antigen and at least 12 avian orthoreoviruses.

repair
repair (re-par′)

Restoration of diseased or damaged tissues naturally by healing processes or artificially, as by surgical means. [M.E., fr. O.Fr., fr. L. re-paro, fr. re-, back, again, + paro, prepare, put in order]
chemical r. conversion of a free radical to a stable molecule.
error-prone r. SYN: SOS r..
excision r. the use of a complementary DNA strand as a template to replace a damaged segment of DNA.
mismatch r. replacement of mismatched base pairs by removal of the incorrect base and replacement with the correct base by DNA polymerase.
recombinatorial r. the incorporation of corresponding DNA of a DNA segment from an identical DNA molecule for the purpose of replacing a damaged segment of DNA.
SOS r. a system that repairs severely damaged bases in DNA by base excision and replacement, even if there is no template to guide base selection. This process is a last resort for r. and is often the cause of mutations. SYN: error-prone r..

repand
repand (re-pand′)

Denoting a bacterial colony with edges marked by a series of slightly concave segments with angular projections at their points of union. [L. repandus, bent or turned back, fr. re-, back, + pandus, curved]

repellent
repellent (re-pel′ent)

1. Capable of driving off or repelling; repulsive. 2. An agent that drives away or prevents annoyance or irritation by insect pests. 3. An astringent or other agent that reduces swelling. [L. re-pello, pp. -pulsus, to drive back]

repetition-compulsion
repetition-compulsion (rep-e-tish′un-kom-pul′shun)

In psychoanalysis, the tendency to repeat earlier experiences or actions, in an unconscious effort to achieve belated mastery over them; a morbid need to repeat a particular behavior such as handwashing or repeated checking to see if the door is locked.

replacement
replacement (re-plas′ment)

1. Restoration. 2. Substitution.
cephalic r. in cases of shoulder dystocia when vaginal delivery cannot be effected, the fetal head is flexed and reinserted into the vagina to re-establish umbilical cord blood flow and delivery performed through cesarean section. SYN: Zavanelli maneuver.

replant
replant (re′plant)

1. To perform replantation. 2. A part or organ so replaced or about to be so replaced.

replantation
replantation (re-plan-ta′shun)

Replacement of an organ or part in its original site and reestablishing its circulation. SYN: reimplantation. [L. re-, again, + planto, pp. -atus, to plant, fr. planta, a sprout, slip]
intentional r. elective extraction of a tooth, obturation of the root canal(s), and replacement of the tooth into the alveolus.

repletion
repletion (re-ple′shun)

SYN: hypervolemia. [L. repletio, fr. re-pleo, pp. -pletus, to fill up]

replica
replica (rep′li-ka)

A specimen for electron microscopic examination obtained by coating a crystalline array or other virus material with carbon; the mold (the r.) obtained after the viral material has been dissolved provides details of structure and arrangement. [It., fr. L.L. re-plico, to fold back]

replicase
replicase (rep′li-kas)

1. Descriptive term for RNA-directed RNA polymerase associated with replication of RNA viruses. 2. An enzyme that replicates nucleic acids.

replicate
replicate (rep′li-kat)

1. One of several identical processes or observations. 2. To repeat; to produce an exact copy.

replication
replication (rep-li-ka′shun)

1. The execution of an experiment or study more than once so as to confirm the original findings, increase precision, and obtain a closer estimate of sampling error. 2. Autoreproduction or duplication, as in mitosis or cellular biology. See autoreproduction. 3. DNA-directed DNA synthesis. [L. replicatio, a reply, fr. replico, pp. -atus, to fold back]
bidirectional r. a situation in which DNA r. proceeds with two r. forks moving in opposite directions around a circle or D-loop-type structure.
conservative r. a hypothetical form of r. in which a double-stranded DNA (dsDNA) produces two daughter dsDNAs, one of which consists of the two original strands while the other daughter DNA consists of two newly synthesized chains.
semiconservative r. r. in which a double-stranded DNA (dsDNA) produces two daughter dsDNAs, each of which contains one of the original chains and one newly synthesized strand.
unidirectional r. r. in which there is movement by a single r. fork.

replicator
replicator (rep′li-ka-ter)

The specific site of a bacterial genome (chromosome) at which replication begins.

replicon
replicon (rep′li-kon)

1. A segment of a chromosome (or of the DNA of a chromosome or similar entity) that can replicate, with its own initiation and termination codons, independently of the chromosome in which it may be located. 2. The replication unit; several are found per DNA in eukaryotic systems. [replication + -on]

repolarization
repolarization (re′po-lar-i-za′shun)

The process whereby the membrane, cell, or fiber, after depolarization, is polarized again, with positive charges on the outer and negative charges on the inner surface.

repositio
repositio

SYN: reposition.

reposition
reposition

Movement returning palm and fingers from opposed position; opposite of opposition. SYN: repositio.

repositioning
repositioning (re′po-zish′un-ing)

1. To place in another position as during an operation. 2. SYN: reduction (1) .
gingival r. surgical relocation of the attached gingiva to eliminate pathosis or to establish more acceptable form and function.
jaw r. the changing of any relative position of the mandible to the maxillae, by altering the occlusion of the natural or artificial teeth or by surgical means.
muscle r. the surgical replacement of a muscle attachment into a more functional position.

repositor
repositor (re-poz′i-ter, -tor)

An instrument used to reposition a displaced organ.

representation
representation

internal r. term used by neurolinguistic programming to denote the way people use mental imagery (visual, auditory, or kinesthetic) to encode experience, the composite of which comprises their internal and external reality.

repressed
repressed (re-prest′)

Subjected to repression.

repression
repression (re-presh′un)

1. In psychotherapy, the active process or defense mechanism of keeping out and ejecting and banishing from consciousness those ideas or impulses that are unacceptable to the ego or superego. 2. Decreased expression of some gene product. [L. re-primo, pp. -pressus, to press back, repress]
catabolite r. the decreased expression of an operon because of elevated levels of a catabolite of a biochemical pathway.
end product r. catabolite r. in which the catabolite is an end product of a particular pathway.
enzyme r. inhibition of enzyme synthesis by some metabolite.
primal r. r. of material never in conscious thought.

repressor
repressor (re-pres′er)

The product of a regulator or r. gene.
active r. a r. that combines directly with an operator gene to repress the operator and its structural genes, thus repressing protein synthesis; an active r. may be repressed by an inducer, with resulting protein synthesis; a homeostatic mechanism for regulation of inducible enzyme systems.
inactive r. a r. that cannot combine with an operator gene until it has combined with a corepressor (usually a product of a protein pathway); after activation, the r. arrests production of the proteins controlled by the operator gene; a homeostatic mechanism for regulation of repressible enzyme systems.

reproducibility
reproducibility (re-pro-dus′i-bil′i-te)

1. Ability to cause to exist again or to present again. 2. Ability to duplicate measurements over long periods of time by different laboratories.

reproduction
reproduction (re-pro-duk′shun)

1. The total process by which organisms produce offspring. SYN: generation (1) , procreation. 2. The recall and presentation in the mind of the elements of a former impression. [L. re-, again, + pro-duco, pp. -ductus, to lead forth, produce]
asexual r. r. other than by union of male and female sex cells. SYN: agamogenesis, agamogony.
cytogenic r. r. by means of unicellular germ cells; includes both sexual r. and asexual r. by means of spores.
sexual r. r. by union of male and female gametes to form a zygote. SYN: gamogenesis, syngenesis.
somatic r. asexual r. by fission or budding of somatic cells.
vegetative r. See asexual r..

reproductive
reproductive (re′pro-duk′tiv)

Relating to reproduction.

reptilase
reptilase (rep′til-as)

An enzyme found in the venom of Bothrops atrox that clots fibrinogen by splitting off its fibrinopeptide. [reptile + -ase]

Reptilia
Reptilia (rep-til′e-a)

A class of vertebrates comprising the alligators, crocodiles, lizards, turtles, tortoises, and snakes. [L. reptilis, ntr. -e, creeping; ntr. as n., reptile]

repullulation
repullulation (re-pul-u-la′shun)

Renewed germination; return of a morbid process or growth. [L. re-, again, + pullulo, pp. -atus, to sprout]

repulsion
repulsion (re-pul′shun)

1. The act of repelling or driving apart, in contrast to attraction. 2. Strong dislike; aversion; repugnance. 3. Coupling phase of genes at linked loci that are borne on opposite chromosomes. See coupling phase. [L. re-pello, pp. -pulsus, to drive back]

requirement
requirement (re-kwir′ment)

1. Something needed. 2. A condition.
minimum protein r. the age-dependent amount of protein required daily in the diet.
quantum r. the number of quanta of light absorbed required for the transformation of one molecule; the inverse of the quantum yield.

RES
RES

Abbreviation for reticuloendothelial system.

resazurin
resazurin (re-saz′u-rin)

A blue compound used as a redox indicator in the reductase test of milk and also as a pH indicator (orange at 3.8, violet at 6.5).

rescinnamine
rescinnamine (re-sin′a-men, -min)

3,4,5-Trimethoxycinnamic acid ester of methyl reserpate; a purified ester alkaloid of the alseroxylon fraction of species of Rauwolfia; chemically and pharmacologically related to reserpine, with similar uses.

research
research (re-surch′, re′surch)

1. (n) The organized quest for new knowledge and better understanding, e.g., of the natural world, determinants of health and disease. Several types of r. are recognized: observational (empiric); analytic; experimental; theoretical; applied. 2. (v) To conduct such scientific inquiry. [O.Fr. re-cerche, fr. cerchier, to search, fr. L. circare, to go around, fr. circus, circle]

resect
resect (re-sekt′)

1. To cut off or remove, especially to cut off the articular ends of one or both bones forming a joint. 2. To excise a segment of a part. [L. re-seco, pp. sectus, to cut off]

resectable
resectable (re-sek′ta-bl)

Amenable to resection.

resection
resection (re-sek′shun)

1. A procedure performed for the specific purpose of removal, as in removal of articular ends of one or both bones forming a joint. 2. To remove a part. 3. SYN: excision (1) .
abdominoperineal r. (APR) a surgical cancer treatment involving r. of the lower sigmoid colon, rectum, anus, and surrounding skin, and formation of a sigmoid colostomy; performed as a synchronous or sequential transabdominal and perineal procedure.
gum r. SYN: gingivectomy.
loop r. SYN: loop excision.
muscle r. shortening of the tendon of the ocular muscle in strabismus.
root r. SYN: apicoectomy.
scleral r. shortening of the outer coat of the eye in retinal separation.
transurethral r. endoscopic removal of the prostate gland or bladder lesions, usually for relief of prostatic obstruction or treatment of bladder malignancies.
wedge r. removal of a wedge-shaped portion of the ovary; used in the treatment of virilizing disorders of ovarian origin, such as the polycystic ovarian syndrome.

resectoscope
resectoscope (re-sek′to-skop)

A special endoscopic instrument for the transurethral electrosurgical removal of lesions involving the bladder, prostate gland, or urethra.

reserpine
reserpine (re-ser′pen, -pin)

An ester alkaloid isolated from the root of certain species of Rauwolfia; it decreases the 5-hydroxytryptamine and catecholamine concentrations in the central nervous system and in peripheral tissues; used in conjunction with other hypotensive agents in the management of essential hypertension and useful as a tranquilizer in psychotic states.

reserve
reserve (re-zerv′)

Something available but held back for later use, as strength or carbohydrates. [L. re-servo, to keep back, r.]
alkali r. the sum total of the basic ions (mainly bicarbonates) of the blood and other body fluids that, acting as buffers, maintain the normal pH of the blood.
breathing r. the difference between the pulmonary ventilation ( i.e., the volume of air breathed under ordinary resting conditions) and the maximum breathing capacity.
cardiac r. the work that the heart is able to perform beyond that required under the ordinary circumstances of daily life, depending upon the state of the myocardium and the degree to which, within physiologic limits, the cardiac muscle fibers can be stretched by the volume of blood reaching the heart during diastole.

reservoir
reservoir (rez′ev-wor)

SYN: receptaculum. [Fr.]
r. of infection living or nonliving material in or on which an infectious agent multiplies and/or develops and is dependent for its survival in nature.
Ommaya r. a plastic container placed in the subgaleal space that is connected to the lateral ventricle or tumor cyst by tubing; it is used to instill medication into, or remove fluid from, the ventricle or tumor cyst.
Pecquet r. SYN: cisterna chyli.
r. of spermatozoa the site where spermatozoa are stored; the distal portion of the tail of the epididymis and the beginning of the ductus deferens.
vitelline r. SYN: vitellarium.

reset nodus sinuatrialis
reset nodus sinuatrialis (re′set no′dus si′noo-a-tre-a′lis)

Reset of the sinoatrial node produced by premature depolarization (usually atrial) when the sum of the duration of the premature cycle and the return cycle is less than twice the spontaneous cycle length. Cf.:nonreset nodus sinuatrialis. SYN: sinus node reset.

resident
resident (rez′i-dent)

A house officer attached to a hospital for clinical training; formerly, one who actually resided in the hospital. SYN: r. physician. [L. resideo, to reside]

residua
residua (re-zid′u-a)

Plural of residuum.

residual
residual (re-zid′u-al)

Relating to or of the nature of a residue.

residue
residue (rez′i-doo)

That which remains after removal of one or more substances. SYN: residuum. [L. residuum]
day r. psychoanalytic term for a dream related to an experience of the previous day.

residuum
residuum, pl .residua (re-zid′u-um, -u-a)

SYN: residue. [L. ntr. of residuus, left behind, remaining, fr. re- sideo, to sit back, remain behind]

resilience
resilience (re-zil′yens)

1. Energy (per unit of volume) released upon unloading. 2. Springiness or elasticity. [L. resilio, to spring back, rebound]

resin
resin (rez′in, roz′in)

1. An amorphous brittle substance consisting of the hardened secretion of a number of plants, probably derived from a volatile oil and similar to a stearoptene. 2. SYN: rosin. 3. A precipitate formed by the addition of water to certain tinctures. 4. A broad term used to indicate organic substances insoluble in water; these monomers are named according to their chemical composition, physical structure, and means for activation or curing, e.g., acrylic r., autopolymer r.. [L. resina]
acrylic r. a general term applied to a resinous material of the various esters of acrylic acid; used as a denture base material, for other dental restorations, and for trays.
activated r. SYN: autopolymer r..
anion-exchange r. See anion exchange, anion exchanger.
autopolymer r., autopolymerizing r. any r. that can be polymerized by chemical catalysis rather than by the application of heat or light; used in dentistry for dental restoration, denture repair, and impression trays. SYN: activated r., cold cure r., cold-curing r., quick cure r., self-curing r..
carbacrylamine resins a mixture of the cation-exchange resins, carbacrylic r. and potassium carbacrylic r. (87.5%), and of the anion-exchange r., polyamine-methylene r. (12.5%), used to increase the fecal excretion of sodium in edema associated with excessive sodium retention by the kidneys, e.g., in congestive heart failure, cirrhosis of the liver, and nephrosis.
cation-exchange r. See cation exchange, cation exchanger.
chemically cured r. a r. that contains an initiator, usually benzoyl peroxide, and an activator, usually a tertiary amine, in separate pastes. When mixed, the amine reacts with the benzoyl peroxide to form free radicals and polymerization occurs.
cholestyramine r. a strongly basic anion-exchange r. in the chloride form, consisting of a copolymer of styrene and divinylbenzene with quaternary ammonium functional groups; it lowers the blood cholesterol by binding the bile acids in the intestine, thus promoting their excretion in the feces instead of reabsorption from the bowel; used in the treatment of hypercholesterolemia, xanthomatous biliary cirrhosis, and other forms of xanthomatosis; also will bind numerous drugs in the intestine, reducing their bioavailability.
cold cure r., cold-curing r. SYN: autopolymer r..
composite r. a synthetic r. usually acrylic based, to which a glass or natural silica filter has been added. Used mainly in dental restorative procedures. [L. compositus, put together, fr. compono, to put together]
copolymer r. synthetic r. produced by joint polymerization of two or more different monomers or polymers.
cross-linked r. SYN: cross-linked polymer.
direct filling r. an autopolymerizing r. especially designed as a dental restorative material.
dual-cure r. a r. that utilizes both light and chemical initiation to activate polymerization.
epoxy r. any thermosetting r. based on the reactivity of epoxy; used as adhesives, protective coatings, and embedding media for electron microscopy.
gum r. the dry exudate from a number of plants, consisting of a mixture of a gum and a r., the former soluble in water but not alcohol, the latter soluble in alcohol but not water.
heat-curing r. r. that requires heat to initiate polymerization.
Indian podophyllum r. r. obtained from Podophyllum emodi; a cathartic and cholagogue.
ion-exchange r. See ion exchange, ion exchanger.
ipomea r. r. obtained from the dried root of Ipomoea orizabensis; a cathartic. SEE ALSO: scammony.
jalap r. r. extracted from the dried tuberous root of Exogonium purga; a purgative.
light-activated r. SYN: light-cured r..
light-cured r. a r. that uses visible or ultraviolet light to excite a photoinitiator, which interacts with an amine to form free radicals and initiate polymerization; used mainly in restorative dentistry. SYN: light-activated r..
melamine r. a plastic material mixed with plaster of Paris for casts. Such a cast is lighter and stronger than one made with plaster of Paris alone. SYN: melamine formaldehyde.
methacrylate r. a translucent plastic material, used for the manufacture of various medical appliances, surgical instruments, and seating components used in total joint replacement; it possesses the optical properties of fused quartz and is readily molded when heated; formerly used in electron microscopy for embedding tissues, now superseded by epoxy resins.
podophyllum r. a r. extracted from the dried roots and rhizomes of Podophyllum peltatum, a perennial herb common in moist, shady situations in the eastern parts of Canada and the United States. The drug has been used by American Indians as a vermifuge and emetic. The chief constituents of the r. belong to the group of lignins, which are C_l18 compounds related biosynthetically to the flavonoids and derived by dimerization of two C₆-C₃ units. The most important ones present in podophyllum r. are podophyllotoxin (about 20%), β-peltatin (about 10%), and α-peltatin (about 5%). All three occur both free and as glucosides. The r. has been used as a purgative but has been replaced by milder agents. It is cytotoxic and used as a paint in the treatment of soft venereal and other warts. SYN: May apple root, podophyllin, wild mandrake.
polyamine-methylene r. a synthetic acid-binding r. used as a gastric antacid.
polyester r. r. in which the polymers are insoluble in most organic solvents and are polymerized by light, heat, or oxygen; used in electron microscopy as a tissue-embedding medium.
quick cure r. SYN: autopolymer r..
quinine carbacrylic r. SYN: azuresin.
self-curing r. SYN: autopolymer r..

resin acids
resin acids

A class of organic compounds derived from various natural plant resins; diterpenes containing a phenanthrene ring system; e.g., abietic acid, pimaric acid, ester gums. SYN: resinic acids.

resinates
resinates (rez′in-ats)

Salts or esters of resin acids.

resines
resines (rez′ens)

Esters of resin acids.

resinic acids
resinic acids

SYN: resin acids.

resinoid
resinoid (rez′i-noyd)

1. A substance containing a resin or resembling one. 2. An extract obtained by evaporating a tincture. 3. Resembling rosin.

resinols
resinols (rez′in-ols)

Resin alcohols.

resinous
resinous (rez′i-nus)

Relating to or derived from a resin.

resistance
resistance (re-zis′tans)

1. A force exerted in opposition to an active force. 2. The opposition in a conductor to the passage of a current of electricity, whereby there is a loss of energy and a production of heat; specifically, the potential difference in volts across the conductor per ampere of current flow; unit: ohm. Cf.:impedance (1) . 3. The opposition to flow of a fluid through one or more passageways ( e.g., blood flow, respiratory gases in the tracheobronchial tree), analogous to (2); units are usually those of pressure difference per unit flow. Cf.:impedance (2) . 4. In psychoanalysis, an individual's unconscious defense against bringing repressed thoughts to consciousness. 5. The ability of red blood cells to resist hemolysis and to preserve their shape under varying degrees of osmotic pressure in the blood plasma. 6. The natural or acquired ability of an organism to maintain its immunity to or to resist the effects of an antagonistic agent, e.g., pathogenic microorganism, toxin, drug. [L. re-sisto, to stand back, withstand]
airway r. in physiology, the r. to flow of gases during ventilation due to obstruction or turbulent flow in the upper and lower airways; to be differentiated during inhalation from r. to inflation due to decreases in pulmonary or thoracic compliance.
bacteriophage r. r. of a bacterial mutant to infection by a bacteriophage to which the parent (wild-type) strain is susceptible.
dicumarol r. [MIM*122700] an autosomal dominant disorder characterized by r. to dicumarol, over and above general variability in tolerance to the drug; caused by mutation in the coumarin 7-hydroxylase gene (CYP2A6) on chromosome 19p.
drug r. the capacity of disease-causing microorganisms to withstand drugs previously toxic to them; achieved by spontaneous mutation or through selective pressure after exposure to the drug in question. Pathogenic microorganisms resist antibiotics by various mechanisms, including the production of enzymes ( e.g., β-lactamases) that chemically inactivate antibiotic molecules. In mixed infections of the respiratory tract, a β-lactamase (penicillinase) produced by one organism ( e.g., Haemophilus influenzae) can inactivate penicillin and so block its effectiveness against other organisms in the mixture that possess no r. of their own ( e.g., group A β-hemolytic streptococci). Usually an organism that has acquired r. to a given antibiotic is resistant to others in the same chemical class. Some bacteria transmit antibiotic r. to their offspring not chromosomally but via plasmids, which lie outside the bacterial nucleus but perform certain genetic functions. Bacteria of one species can develop r. to certain antibiotics by acquiring plasmids from bacteria of another species.Drug r. is a growing problem worldwide. Many strains of bacteria, fungi, and parasites have developed r., including pneumococci, gonococci, salmonellae, Mycobacterium tuberculosis, Tinea tonsurans, and Plasmodium falciparum. In some parts of the U.S., 40% of pneumococcal isolates and 90% of staphylococci are resistant to penicillin. The prevalence of both vancomycin-resistant enterococci and methicillin-resistant Staphylococcus aureus has increased 20-fold since 1989. Factors favoring development of antibiotic r. include inappropriate prescribing of antibiotics (e.g., to treat viral infections); indiscriminate use of newly developed, extended-spectrum agents; empiric and broad-spectrum treatment of infections in certain populations (e.g., children, the elderly, and residents of long-term care facilities); prescribing of sublethal doses; and failure of patients to complete courses of antibiotic treatment. The Centers for Disease Control and Prevention estimates that U.S. physicians write 50 million unnecessary antibiotic prescriptions annually, including 17 million to treat the common cold. Infectious disease experts and public health authorities have called for restraint by primary care physicians in prescribing antibiotics, particularly for children and for uncomplicated upper respiratory infections, acute bronchitis (nearly always viral), and acute sinusitis and otitis media (in neither of which have reliable diagnostic criteria for bacterial infection been established). They have also stressed the importance of public education, since inappropriate expectations of patients or their parents have been a driving factor in antibiotic overuse by physicians. Administration of antibiotics to livestock animals, chiefly for disease prophylaxis and growth promotion, has also contributed to the emergence of resistant strains of bacteria.
expiratory r. r. to flow of gas out of the lungs or the total r. to flow of gas during the expiratory phase of the respiratory cycle.
impact r. the ability of a lens for eyewear to withstand impact without shattering or breaking, i.e., of a 38-inch steel ball dropped 50 ft; criteria for determination of impact r. are specified by U.S. regulations.
inductive r. SYN: reactance.
insulin r. diminished effectiveness of insulin in lowering plasma glucose levels, arbitrarily defined as a daily requirement of at least 200 units of insulin to prevent hyperglycemia or ketosis; usually due to binding of insulin or insulin receptor sites by antibodies; associated with obesity, ketoacidosis, and infection.Impairment of the normal response of muscle and other cells to endogenous or exogenous insulin often complicates the deficiency of endogenous insulin that is characteristic of type 2 diabetes mellitus. It is a peripheral phenomenon and can occur even when the quality and quantity of insulin produced by the pancreas are normal. It apparently results from a decrease in the number of insulin receptor sites on cells, a malfunction of the biochemical glucose transport system, or both. Insulin r. is often associated with high levels of circulating antibody to insulin receptors. The phenomenon of insulin r. explains why some people with type 2 diabetes have hyperinsulinemia in the fasting state, often coexisting with elevated plasma glucose levels. Insulin r. correlates closely with obesity in diabetes. It occurs less frequently in lean diabetics, whose principal problem is usually primary failure of insulin production. Insulin r. is often seen in persons with or without frank diabetes who have other endocrine or systemic disorders, including dyslipidemias, hypertension, hyperuricemia, and chronic infection. Some women with polycystic ovaries, hirsutism, and anovulation also have insulin r. and hyperinsulinemia. Troglitazone, a newer agent used in the treatment of type 2 diabetes mellitus, improves insulin sensitivity.
multidrug r. the insensitivity of various tumors to a variety of chemically related anticancer drugs; mediated by a process of inactivating the drug or removing it from the target tumor cells.
mutual r. SYN: antagonism.
peripheral r. SYN: total peripheral r..
synaptic r. the ease or difficulty with which a nerve impulse can cross a synapse.
systemic vascular r. an index of arteriolar compliance or constriction throughout the body; proportional to the blood pressure divided by the cardiac output.
thyrotropin r. an autosomal recessive disorder in which the thyrocytes are unresponsive to thyrotropin. Cf.:pseudohypoparathyroidism.
total peripheral r. (TPR) the total r. to flow of blood in the systemic circuit; the quotient produced by dividing the mean arterial pressure by the cardiac minute-volume. SYN: peripheral r..

resistivity
resistivity (re′zis-tiv′i-te)

A measure of a material's resistance to the passage of electrical current; the reciprocal of conductivity. [L. re-sito, to withstand]

resistor
resistor (re-zis′ter, -tor)

An element included in an electric circuit to provide resistance to the flow of current.

resolution
resolution (rez-o-loo′shun)

1. The arrest of an inflammatory process without suppuration; the absorption or breaking down and removal of the products of inflammation or of a new growth. See line pairs, under pair. 2. The optical ability to distinguish detail such as the separation of closely adjacent objects. SYN: resolving power (3) . [L. resolutio, a slackening, fr. re-solvo, pp. -solutus, to loosen, relax]

resolvase
resolvase (re-sol′vaz)

A gene encoded by a transposon that can catalyze a second stage of transposition as well as participate in the regulation of its own expression. [resolve + -ase]

resolve
resolve (re-zolv′)

To return or cause to return to the normal, particularly without suppuration, said of a phlegmon or other form of inflammation. [L. resolvo, to loosen]

resolvent
resolvent (re-zol′vent)

1. Causing resolution. 2. An agent that arrests an inflammatory process or causes the absorption of a neoplasm.

resonance
resonance (rez′o-nans)

1. Sympathetic or forced vibration of air in the cavities above, below, in front of, or behind a source of sound; in speech, modification of the quality ( e.g., harmonics) of a tone by the passage of air through the chambers of the nose, pharynx, and head, without increasing the intensity of the sound. 2. The sound obtained on percussing a part that can vibrate freely. 3. The intensification and hollow character of the voice sound obtained on auscultating over a cavity. 4. In chemistry, the manner in which electrons or electric charges are distributed among the atoms in compounds that are planar and symmetric, particularly those with conjugated (alternating) double bonds; the existence of r. in the latter case lowers the energy content and increases the stability of a compound. 5. The natural or inherent frequency of any oscillating system. 6. SYN: resonant frequency. [L. resonantia, echo, fr. re-sono, to resound, to echo]
amphoric r. a percussion sound, like that produced by striking a large empty bottle, obtained by percussing over a pulmonary cavity. SYN: cavernous r..
bandbox r. SYN: vesiculotympanitic r..
bellmetal r. in cases of a large pulmonary cavity or of pneumothorax, a clear metallic sound obtained by striking a coin, held against the chest, by another coin, or by flicking the chest wall with one's fingernail; the sound is heard on auscultating the chest wall on the same side anteroposteriorly. SYN: anvil sound, bell sound, coin test.
cavernous r. SYN: amphoric r..
cracked-pot r. a peculiar sound, resembling that heard on striking a cracked pot, elicited on percussing over a pulmonary cavity that communicates with a bronchial tube, when the patient's mouth is open. SYN: cracked-pot sound.
electron paramagnetic r. (EPR) SYN: electron spin r..
electron spin r. (ESR) a spectrometric method, based on measurement of electron spins and magnetic moments, for detecting and estimating free radicals in reactions and in biologic systems. SYN: electron paramagnetic r..
hydatid r. a peculiar vibratile r. heard on auscultatory percussion over a hydatid cyst.
nuclear magnetic r. (NMR) the phenomenon in which certain atomic nuclei possessing a magnetic moment will precess around the axis of a strong external magnetic field, the frequency of precession (Larmor frequency) being specific for each nucleus and the strength of the magnetic field; spinning nuclei induce their own oscillating magnetic fields and therefore emit electromagnetic radiation that can produce a detectable signal at the Larmor frequency. NMR is used as a method of identifying covalent bonds and is applied clinically in magnetic r. imaging.
skodaic r. a peculiar, high-pitched sound, less musical than that obtained over a cavity, elicited by percussion just above the level of a pleuritic effusion. SYN: Skoda sign, Skoda tympany.
tympanitic r. SYN: tympany.
vesicular r. the sound obtained on percussing over the normal lungs.
vesiculotympanitic r. a peculiar, partly tympanitic, partly vesicular sound, obtained on percussion in cases of pulmonary emphysema. SYN: bandbox r., wooden r..
vocal r. (VR) the voice sounds as heard on auscultation of the chest.
wooden r. SYN: vesiculotympanitic r..

resonator
resonator (rez′o-na-ter)

A device for employing inductance to create an electric current of very high potential and small volume.

resorb
resorb (re-sorb′)

To reabsorb; to absorb what has been excreted, as an exudate or pus. [L. re-sorbeo, to suck back]

resorcin
resorcin (re-zor′sin)

SYN: resorcinol.

resorcinol
resorcinol (re-zor′si-nol)

An external antiseptic in psoriasis, eczema, seborrhea, and ringworm; pyrocatechol and hydroquinone are isomers of r.. SYN: resorcin.
r. monoacetate used externally in the treatment of acne, sycosis, and seborrhea.
r. phthalic anhydride SYN: fluorescein.

resorcinolphthalein
resorcinolphthalein (re-zor′si-nol-thal′e-in)

SYN: fluorescein.
r. sodium SYN: fluorescein sodium.

resorption
resorption (re-sorp′shun)

1. The act of resorbing. 2. A loss of substance by lysis, or by physiologic or pathologic means.
bone r. the removal of osseous tissue.
gingival r. SYN: gingival recession.
horizontal r. SYN: horizontal atrophy.
internal r. a loss of tooth structure originating within the pulp cavity.
ridge r. a loss in the volume and size of the alveolar portion of the mandible or maxilla.
root r. dissolution of the root of a tooth; either external, with loss or blunting of the apical portion, or internal, with loss of dentin from the inside (pulpal) part of the root area.

respirable
respirable (re-spir′a-bl, res′pi-ra-bl)

Capable of being breathed.

respiration
respiration (res-pi-ra′shun)

1. A fundamental process of life, characteristic of both plants and animals, in which oxygen is used to oxidize organic fuel molecules, providing a source of energy as well as carbon dioxide and water. In green plants, photosynthesis is not considered r. 2. SYN: ventilation (2) . [L. respiratio, fr. respiro, pp. -atus, to exhale, breathe]
abdominal r. breathing effected mainly by the action of the diaphragm.
aerobic r. a form of r. in which molecular oxygen is consumed and carbon dioxide and water are produced.
amphoric r. a sound like that made by blowing across the mouth of a bottle, heard on auscultation in some cases in which a large pulmonary cavity exists, or occasionally in pneumothorax.
anaerobic r. a form of r. in which molecular oxygen is not consumed; e.g., nitrate r., sulfate r..
artificial r. SYN: artificial ventilation.
assisted r. SYN: assisted ventilation.
Biot r. completely irregular breathing pattern, with continually variable rate and depth of breathing; results from lesions in the respiratory centers in the brainstem, extending from the dorsomedial medulla caudally to the obex. SYN: ataxic breathing, Biot breathing, respiratory ataxia.
bronchial r. a tubular blowing sound caused by the passage of air through a bronchus in an area of consolidated lung tissue.
bronchovesicular r. combined bronchial and vesicular r..
cavernous r. a hollow reverberating sound heard on auscultation over a cavity in the lung.
Cheyne-Stokes r. the pattern of breathing with gradual increase in depth and sometimes in rate to a maximum, followed by a decrease resulting in apnea; the cycles ordinarily are 30 seconds to 2 minutes in duration, with 5–30 seconds of apnea; seen with bilateral deep cerebral hemispheric lesions, with metabolic encephalopathy, and, characteristically, in coma from affection of the nervous centers of r..
cogwheel r. the inspiratory sound interrupted by one or two by silent intervals. SYN: interrupted r., jerky r..
controlled r. SYN: controlled ventilation.
costal r. SYN: thoracic r..
diffusion r. maintenance of oxygenation during apnea by intratracheal insufflation of oxygen at high flow rates. SYN: apneic oxygenation.
electrophrenic r. the rhythmic electric stimulation of the phrenic nerve by an electrode applied to the skin at the motor points of the phrenic nerve; it is used in paralysis of the respiratory center resulting from acute bulbar poliomyelitis.
external r. the exchange of respiratory gases in the lungs as distinguished from internal or tissue r..
forced r. voluntary hyperventilation.
internal r. SYN: tissue r..
interrupted r. SYN: cogwheel r..
jerky r. SYN: cogwheel r..
Kussmaul r. deep, rapid r. characteristic of diabetic or other causes of acidosis. SYN: Kussmaul-Kien r..
Kussmaul-Kien r. SYN: Kussmaul r..
labored r. difficult, usually deep, breathing in patients with cardiac or pulmonary disease or disease affecting nervous system control of ventilation.
mouth-to-mouth r. a method of artificial ventilation involving an overlap of the patient's mouth (and nose in small children) with the operator's mouth to inflate the patient's lungs by blowing, followed by an unassisted expiratory phase brought about by elastic recoil of the patient's chest and lungs; repeated 12–16 times a minute; where the nose is not covered by the operator's mouth, the nostrils must be closed by pinching.
nitrate r. the process of r. used by some anaerobic organisms, in which nitrate rather than molecular oxygen is used to oxidize organic molecules to obtain energy.
paradoxical r. deflation of the lung during inspiration and inflation of the lung during the phase of expiration; seen in the lung on the side of an open pneumothorax.
puerile r. an exaggeration of the normal respiratory sounds, heard in children and in adults after exertion.
stertorous r. harsh, noisy breathing usually heard in a comatous patient. SYN: stertorous breathing.
sulfate r. the process of r. used by some anaerobic organisms, in which sulfate rather than molecular oxygen is used to oxidize organic molecules to obtain energy.
thoracic r. r. effected chiefly by the action of the intercostal and other muscles that raise the ribs, causing expansion of the chest. SYN: costal r..
tissue r. the interchange of gases between the blood and the tissues. SYN: internal r..
tubular r. high-pitched bronchial r..
vesicular r. the respiratory murmur heard on auscultating over the normal lung. SYN: respiratory murmur, vesicular murmur.
vesiculocavernous r. cavernous r., due to the presence of a cavity, mingled with the vesicular murmur of the surrounding normal lung tissue.

respirator
respirator (res′pi-ra-ter, -tor)

1. An apparatus for administering artificial respiration in cases of respiratory failure. 2. An appliance fitting over the mouth and nose, used for the purpose of excluding dust, smoke, or other irritants, or of otherwise altering the air before it enters the respiratory passages. SYN: inhaler (1) . SYN: ventilator.
cuirass r. one of several types of respirators producing alternating negative pressure about the thoracic cage; now rarely used.
Drinker r. a mechanical r. in which the body (except the head) is encased within a metal tank, which is sealed at the neck with an airtight gasket; artificial respiration is induced by making the air pressure inside negative. SYN: iron lung, tank r..
pressure-controlled r. a r. that provides a predetermined pressure to gases during inhalation, the volume of gas moved being variable, depending upon resistance.
tank r. SYN: Drinker r..
volume-controlled r. a r. that provides a predetermined volume of gases during inhalation, with the pressure required to move that volume remaining variable, depending upon resistance.

respiratory
respiratory (res′pi-ra-tor-e, re-spir′a-tor-e)

Relating to respiration.

respire
respire (re-spir′)

1. To breathe. 2. To consume oxygen and produce carbon dioxide by metabolism. [L. respiro, to breathe]

respirometer
respirometer (res-pi-rom′e-ter)

1. An instrument for measuring the extent of the respiratory movements. 2. An instrument for measuring oxygen consumption or carbon dioxide production, usually of an isolated tissue. [L. respiro, to breathe, + G. metron, measure]
Dräger r. an inferential meter to measure tidal and minute volume from the number of revolutions of a vane rotated by the gas stream as the latter passes through two lightweight lozenge-shaped meshing rotors.
Wright r. an inferential meter to measure tidal and minute volume from the number of revolutions of a vane rotated by the gas stream as the latter passes through 10 tangential slots in a cylindric stator ring to turn a flat two-bladed rotor; also called Wright spirometer.

response
response (re-spons′)

1. The reaction of a muscle, nerve, gland, or other excitable tissue to a stimulus. 2. Any act or behavior, or its constituents, that a living organism is capable of emitting. Reflexes are usually excluded because they are typically elicited by a specifiable (unconditioned or natural) stimulus rather than emitted under circumstances in which the stimulus was not specifiable. [L. responsus, an answer]
acute phase r. SYN: acute phase reaction.
anamnestic r. (an′am-nes-tik) SYN: secondary immune r.. See immune r..
auditory brainstem r. (ABR) an electrophysiologic measure of auditory function utilizing computer-averaged responses produced by the auditory nerve and the central auditory pathways principally in the brainstem to repetitive acoustic stimuli. ABR is also used to locate the lesion and determine the type of hearing impairment (sensory versus neural). SYN: brainstem evoked r..
automatic auditory brainstem r. a technique of ABR in which the stimulus modification is programmed on the basis of the electrical responses recorded. The device determines automatically if predetermined thresholds have been achieved. It is useful in newborn hearing screening.
biphasic r. 1. two separate and distinct responses that are separated in time; 2. immediate reaction to an antigenic challenge followed by a recurrence of symptoms after an interval of quiescence.
blink r. a r. elicited during nerve conduction studies, consisting of muscle action potentials evoked from orbicularis oculi muscles after brief electric or mechanical stimuli to the cutaneous area supplied by the ophthalmic branch of the trigeminal nerve. Characteristically, there is an early r. (approximately 10 ms after stimulus) ipsilateral to the stimulation site (labeled R1) and bilateral late responses (approximately 30 ms after stimulus; labeled R2); the latter are responsible for the visible twitch of the orbicularis oculi muscles.
booster r. SYN: secondary immune r.. See immune r..
brainstem evoked r. (BSER) SYN: auditory brainstem r..
conditioned r. a r. already in an individual's repertoire but which, through repeated pairings with its natural stimulus, has been acquired or conditioned anew to a previously neutral or conditioned stimulus. See conditioning. Cf.:unconditioned r..
Cushing r. SYN: Cushing phenomenon.
depletion r. subnormal metabolic r. to trauma in a person whose physiologic processes are already depressed by disease.
early-phase r. prompt onset of symptoms following an antigenic stimulus.
evoked r. an alteration in the electrical activity of a region of the nervous system through which an incoming sensory stimulus is passing; may be somatosensory (SER), brainstem auditory (BAER), or visual (VER). SEE ALSO: evoked potential.
flight or fight r. emergency theory.
galvanic skin r. (GSR) a measure of changes in emotional arousal recorded by attaching electrodes to any part of the skin and recording changes in moment-to-moment perspiration and related autonomic nervous system activity. SYN: galvanic skin reaction, galvanic skin reflex, psychogalvanic reaction, psychogalvanic skin reaction, psychogalvanic reflex, psychogalvanic skin reflex, psychogalvanic r., psychogalvanic skin r..
Henry-Gauer r. inhibition of antidiuretic hormone secretion due to a rise in atrial pressure that stimulates atrial stretch receptors.
immune r. 1. any r. of the immune system to an antigen including antibody production and/or cell-mediated immunity; 2. the r. of the immune system to an antigen (immunogen) that leads to the condition of induced sensitivity; the immune r. to the initial antigenic exposure (primary immune r.) is detectable, as a rule, only after a lag period of from several days to 2 weeks; the immune r. to a subsequent stimulus (secondary immune r.) by the same antigen is more rapid than in the case of the primary immune r..
isomorphic r. a r. to trauma at sites of injury in previously uninvolved areas of patients with skin diseases such as psoriasis and lichen planus, typically with linear lesions at sites of scratching or a scar. SYN: Köbner phenomenon.
late auditory-evoked r. r. of the auditory cortex to acoustic stimulation.
late-phase r. recurrence of symptoms after an appreciable interval following challenge with an antigen; preceded by an initial early-phase r..
level-dependent frequency r. one of several strategies used in hearing aids to alter the balance in amplification between high- and low-frequency sounds.
middle latency r. a r. to acoustic stimulation recorded from the auditory cortex of the brain.
myotonic r. failure of muscle relaxation caused by repetitive discharge of muscle fiber action potentials.
oculomotor r. widespread myogenic potential evoked by visual stimuli.
orienting r. SYN: orienting reflex.
postural sway r. the body sway induced by vestibular stimulation.
primary immune r. immune r..
psychogalvanic r. (PGR) , psychogalvanic skin r. SYN: galvanic skin r..
recruiting r. SYN: recruitment (2) .
relaxation r. an integrated hypothalamic reaction resulting in decreased sympathetic nervous system activity which, physiologically and psychologically, is almost a mirror image of the body's responses to Cannon emergency theory (flight or fight r.); can be self-induced through the use of techniques associated with transcendental meditation, yoga, and biofeedback. SEE ALSO: emergency theory.
secondary immune r. SYN: anamnestic r., booster r..immune r..
sonomotor r. widespread myogenic potential evoked by click stimulation.
stringent r. the cellular r. to amino acid starvation that reduces the amount of ribosomes to what can be employed under the nutrient conditions.
target r. SYN: operant.
triple r. the triphasic r. to the firm stroking of the skin. Phase 1 is the sharply demarcated erythema that follows a momentary blanching of the skin and is the result of release of histamine from the mast cells. Phase 2 is the intense red flare extending beyond the margins of the line of pressure but in the same configuration, and is the result of arteriolar dilation; also called axon flare because it is mediated by axon reflex. Phase 3 is the appearance of a line wheal in the configuration of the original stroking.
unconditioned r. a r., such as salivation, which is a part of the animal or human repertoire. Cf.:conditioned r..

rest
rest

1. Quiet; repose. [A.S. raest] 2. To repose; to cease from work. [A.S. raestan] 3. A group of cells or a portion of fetal tissue that has become displaced and lies embedded in tissue of another character. [L. restare, to remain] 4. In dentistry, an extension from a prosthesis that affords vertical support for a restoration.
adrenal r. SYN: accessory adrenal.
bed r. maintenance of the recumbent position, in bed, to minimize activity and help recovery from disease; formerly used extensively in treatment of tuberculosis, myocardial infarction, and other diseases.
cingulum r. the rigid part of a removable partial denture supported by a prepared r. area on the cingulum of an anterior tooth or crown.
incisal r. the portion of a removable partial denture supported by an incisal edge.
lingual r. a metallic extension onto the lingual surface of a tooth to provide support or indirect retention for a removable partial denture.
Malassez epithelial rests epithelial remains of Hertwig root sheath in the periodontal ligament.
Marchand r. SYN: Marchand adrenals, under adrenal.
mesonephric r. SYN: wolffian r..
occlusal r. a rigid extension of a removable partial denture onto the occlusal surface of a posterior tooth for support of the prosthesis.
precision r. a r. consisting of closely interlocking parts.
rests of Serres remnants of dental lamina epithelium entrapped within the gingiva.
Walthard cell r. a nest of epithelial cells occurring in the peritoneum of the uterine tubes or ovary; when neoplastic, possibly comprising one of the components of the Brenner tumor.
wolffian r. remnants of the wolffian duct in the female genital tract that give rise to cysts; e.g., Gartner cyst. SYN: mesonephric r..

restenosis
restenosis (re′sten-o-sis)

Recurrence of stenosis after corrective surgery on the heart valve; narrowing of a structure (usually a coronary artery) following the removal or reduction of a previous narrowing. [re-, + G. stenosis, a narrowing]

restiform
restiform (res′ti-form)

Ropelike; rope-shaped; referring to the r. body, the larger (lateral) part of the inferior cerebellar peduncle; contains fibers from the spinal cord (spinocerebellar) and medulla (cuneo-, olivo-, reticulocerebellar, etc.) to cerebellum. [L. restis, rope, + forma, form]

restitope
restitope (res′ti-top)

The part of the T cell receptor that associates with the class II major histocompatibility molecule. [restriction + -tope]

restitution
restitution (res-ti-too′shun)

In obstetrics, the return of the rotated head of the fetus to its natural relation with the shoulders after its emergence from the vulva. [L. restitutio, act of restoring]

restoration
restoration (res-to-ra′shun)

In dentistry: 1. A prosthetic r. or appliance; a broad term applied to any inlay, crown, bridge, partial denture, or complete denture that restores or replaces lost tooth structure, teeth, or oral tissues. 2. A plug or stopping; any substance such as gold, amalgam, etc., used for restoring the portion missing from a tooth as a result of removing decay in the tooth. [L. restauro, pp. -atus, to restore, to repair]
acid-etched r. the r. of tooth structure with a resin after the surface of the tooth has been treated with an acid solution that etches the tooth surface, thereby increasing retention of the r..
combination r. a tooth r. of two or more materials applied in layers.
compound r. a r. of more than one surface of a tooth.
direct acrylic r. a direct resin r. of autopolymerizing acrylic.
direct composite resin r. SYN: direct resin r..
direct resin r. a direct r. made by inserting a plastic mix of auto- or light-polymerized resins in a cavity prepared in a tooth. SYN: direct composite resin r..
overhanging r. a r. with excessive material at the junction of the r. margin and the tooth.
permanent r. a definitive r., in contradistinction to a temporary or provisional r..
provisional r. SYN: temporary r..
root canal r. a gutta-percha, silver, or plastic cone that has been carried into a root canal, either alone or in conjunction with a cement, paste, or solvent, for the purpose of obturating the canal space.
silicate r. r. of lost tooth structure made with silicate cement.
temporary r. a r. to be used for a limited period of time, in contradistinction to a permanent r.. SYN: provisional r..

restorative
restorative (re-stor′a-tiv)

1. Renewing health and strength. 2. An agent that promotes a renewal of health or strength. [L. restauro, to restore]

restraint
restraint (re-strant′)

In hospital psychiatry, intervention to prevent an excited or violent patient from doing harm to self or others; may involve the use of a camisole (straightjacket). [O. Fr. restrainte]

restriction
restriction (re-strik′shun)

1. The process with which foreign DNA that has been introduced into a prokaryotic cell becomes ineffective. 2. A limitation.
asymmetric fetal growth r. normal fetal head size as a result of preferential shunting of blood to brain, and decreased abdominal circumference from decreased adipose tissue and liver size; probably caused by placental insufficiency.
fetal growth r. fetal weight ≤5th percentile for gestational age. SYN: intrauterine growth retardation.
lactase r. an inherited trait in which there is low lactase activity and thus there is defective lactose intestinal metabolism. Cf.:lactase persistence.
MHC r. T helper cells only recognize an antigen that is presented with class II major histocompatibility antigens whereas T cytotoxic cells usually only recognize a processed antigen in conjunction with class I major histocompatibility antigens.
symmetric fetal growth r. proportional reduction in fetal head and body size, commonly constitutional or caused by an early intrauterine insult such as infection.

resuscitate
resuscitate (re-sus′i-tat)

To perform resuscitation. [L. resuscito, to raise up again, revive]

resuscitation
resuscitation (re-sus′i-ta′shun)

Revival from potential or apparent death. [L. resuscitatio]
cardiopulmonary r. (CPR) restoration of cardiac output and pulmonary ventilation following cardiac arrest and apnea, using artificial respiration and manual closed-chest compression or open-chest cardiac massage.
mouth-to-mouth r. mouth-to-mouth respiration (q.v.) employed as part of emergency cardiopulmonary r..

retainer
retainer (re-tan′er)

Any type of clasp, attachment, or device used for the fixation or stabilization of a prosthesis; an appliance used to prevent the shifting of teeth following orthodontic treatment.
continuous bar r. a metal bar, usually resting on lingual surfaces of teeth, to aid in their stabilization and to act as indirect retainers. SYN: continuous clasp.
direct r. a clasp or attachment applied to an abutment tooth for the purpose of maintaining a removable appliance in position.
extracoronal r. a r. that depends upon contact with the outer circumference of the crown of a tooth for its retentive qualities.
Hawley r. a removable wire and acrylic palatal appliance used to retain or stabilize the teeth in their new position following orthodontic tooth movement; with modifications it can be used to move teeth as an active orthodontic appliance. SYN: Hawley appliance.
indirect r. a part of a removable partial denture that assists the direct retainers in preventing occlusal displacement of the distal extension bases by functioning through lever action on the opposite side of the fulcrum line.
intracoronal r. a r. that depends upon components placed within the crown portion of a tooth for its retentive qualities.
matrix r. a mechanical device designed to hold a matrix around a tooth during restorative procedures, usually by engaging the ends of the matrix band and drawing the band tight.
space r. SYN: space maintainer.

retardate
retardate (re-tahr′dat)

A mildly pejorative term, which is decreasing in usage, for a person who has mental retardation. [L. retardo, to delay, hinder]

retardation
retardation (re-tahr-da′shun)

Slowness or limitation of development.
intrauterine growth r. SYN: fetal growth restriction.
mental r. subaverage general intellectual functioning that originates during the developmental period and is associated with impairment in adaptive behavior. The American Association on Mental Deficiency lists eight medical classifications and five psychologic classifications; the latter five replace the three former classifications of moron, imbecile, and idiot. Mental r. classification requires assignment of an index for performance relative to a person's peers on two interrelated criteria: measured intelligence (IQ) and overall socioadaptive behavior (a judgmental rating of the individual's relative level of performance in school, at work, at home, and in the community). In general an IQ of 70 or below indicates mental r. (mild = 50/55–70; moderate = 35/40–50/55; severe = 20/25–35/40; profound = below 20/25); an IQ of 70–85 signifies borderline intellectual functioning. SYN: amentia (1) , mental deficiency, oligophrenia.
psychomotor r. slowed psychic activity or motor activity, or both.
viscoelastic r. a technique for the measurement of the molecular weight of large DNA molecules; the DNA is stretched by hydrodynamic shear forces and, when the molecules relax, the relaxation time is measured.

retarder
retarder (re-tar′der)

An agent used to slow the chemical hardening of gypsum, resins, or impression materials used in dentistry.

retch
retch

To make an involuntary effort to vomit. [A.S. hraecan, to hawk]

retching
retching

Gastric and esophageal movements of vomiting without expulsion of vomitus. SYN: dry vomiting, vomiturition.

rete
rete, pl .retia (re′te; re′she-a, -te-a)

1. SYN: network (1) . 2. A structure composed of a fibrous network or mesh. [L. a net]
r. acromiale arteriae thoracoacromialis [TA] SYN: acromial anastomosis of the thoracoacromial artery.
r. arteriosum [TA] SYN: arterial plexus.
r. articulare cubiti [TA] SYN: cubital anastomosis.
r. articulare genus [TA] SYN: genicular anastomosis.
r. calcaneum [TA] SYN: calcaneal anastomosis.
r. canalis hypoglossi SYN: venous plexus of canal of hypoglossal nerve.
r. carpale dorsale [TA] SYN: dorsal carpal arterial arch.
r. carpi posterius SYN: dorsal carpal arterial arch.
r. cutaneum corii the network of vessels parallel to the surface between the corium and the tela subcutanea.
r. foraminis ovalis SYN: venous plexus of foramen ovale.
Haller r. SYN: r. testis.
r. halleri SYN: r. testis.
r. malleolare laterale [TA] SYN: lateral malleolar network.
r. malleolare mediale [TA] SYN: medial malleolar network.
malpighian r. SYN: malpighian stratum.
r. mirabile [TA] a vascular network interrupting the continuity of an artery or vein, such as occurs in the glomeruli of the kidney (arterial) or in the liver (venous).
r. ovarii a transient network of cells in the developing ovary; homologous to the r. testis.
r. patellare [TA] SYN: patellar anastomosis.
r. subpapillare the network of vessels between the papillary and reticular strata of the corium.
r. testis [TA] the network of canals at the termination of the straight tubules in the mediastinum testis. SYN: Haller r., r. halleri.
r. vasculosum articulare [TA] SYN: articular vascular plexus.
r. venosum dorsale manus [TA] SYN: dorsal venous network of hand.
r. venosum dorsale pedis [TA] SYN: dorsal venous network of foot.
r. venosum plantare [TA] SYN: plantar venous network.

retention
retention (re-ten′shun)

1. The keeping in the body of what normally belongs there, especially the retaining of food and drink in the stomach. 2. The keeping in the body of what normally should be discharged, as urine or feces. 3. Retaining that which has been learned so that it can be utilized later as in recall, recognition, or, if r. is partial, relearning. SEE ALSO: memory. 4. Resistance to dislodgement. 5. In dentistry, a passive period following treatment when a patient is wearing an appliance or appliances to maintain or stabilize the teeth in the new position into which they have been moved. [L. retentio, a holding back]
denture r. the means by which dentures are held in position in the mouth.
direct r. r. obtained in a removable partial denture by the use of attachments or clasps that resist their removal from the abutment teeth.
indirect r. r. obtained in a removable partial denture through the use of indirect retainers.
partial denture r. the fixation of a removable partial denture by the use of clasps, indirect retainers, or precision attachments.

retia
retia (re′she-a, -te-a)

Plural of rete. [L.]

retial
retial (re′she-al)

Relating to a rete.

reticul- reticul-

See reticulo-.

reticula
reticula (re-tik′u-la)

Plural of reticulum. [L.]

reticular
reticular, reticulated (re-tik′u-lar, -lat-ed)

Relating to a reticulum.

reticulation
reticulation (re-tik-u-la′shun)

The presence or formation of a reticulum or network, such as that observed in the red blood cells during active regeneration of blood. Also used to describe a chest radiographic pattern. See reticulonodular pattern.

reticulin
reticulin (re-tik′u-lin)

Name given to the chemical substance of reticular fibers, which once were thought to be distinct from collagen by reason of their distinctive structure and staining properties but are now regarded as type III collagen (with its associated proteoglygans and structural glycoproteins).

reticulo- reticulo-, reticul-

Reticulum; reticular. [L. reticulum, a small net, dim. of rete, a net]

reticulocyte
reticulocyte (re-tik′u-lo-sit)

A young red blood cell containing a basophilic cytoplasmic network precipitated by brilliant cresyl blue representing residual polyribosomes; such cells become more numerous during the process of active blood regeneration. SEE ALSO: erythroblast. SYN: reticulated corpuscle, skein cell. [reticulo- + G. kytos, cell]

reticulocytopenia
reticulocytopenia (re-tik′u-lo-si-to-pe′ne-a)

Paucity of reticulocytes in the blood. SYN: reticulopenia. [reticulocyte + G. penia, poverty]

reticulocytosis
reticulocytosis (re-tik′u-lo-si-to′sis)

An increase in the number of circulating reticulocytes above the normal, which is less than 1% of the total number of red blood cells; it occurs during active blood regeneration (stimulation of red bone marrow) and in certain anemias, especially congenital hemolytic anemia. [reticulocyte + G. osis, condition]

reticuloendothelial
reticuloendothelial (re-tik′u-lo-en-do-the′le-al)

Denoting or referring to reticuloendothelium. See r. system.

reticuloendothelioma
reticuloendothelioma (re-tik′u-lo-en′do-the-le-o′ma)

Obsolete term for a localized reticulosis, or neoplasm derived from reticuloendothelial tissue. [reticuloendothelium + G. -oma, tumor]

reticuloendothelium
reticuloendothelium (re-tik′u-lo-en-do-the′le-um)

The cells making up the reticuloendothelial system. [reticulo- + endothelium]

reticulohistiocytoma
reticulohistiocytoma (re-tik′u-lo-his′te-o-si-to′ma)

A solitary skin nodule composed of glycolipid-containing multinucleated large histiocytes; multiple lesions sometimes occur in association with arthritis. [reticulo- + histiocytoma]

reticulohistiocytosis
reticulohistiocytosis (re-tik′u-lo-his′te-o-si-to′sis)

See reticulosis.
multicentric r. a rare disease in which cutaneous papules composed of histiocytes containing glycolipids are associated with polyarthritis, often leading to shortening of the fingers.

reticuloid
reticuloid (re-tik′u-loyd)

1. Resembling a reticulosis. 2. A condition resembling reticulosis.
actinic r. chronic pruritic erythema beginning on sun-exposed areas in elderly males, with marked thickening and ridging of exposed skin simulating lymphoma; there is infiltration by atypical CD8-positive T lymphocytes.

reticulopenia
reticulopenia (re-tik′u-lo-pe′ne-a)

SYN: reticulocytopenia.

reticulosis
reticulosis (re-tik-u-lo′sis)

An increase in histiocytes, monocytes, or other reticuloendothelial elements. [reticulo- + G. -osis, condition]
benign inoculation r. SYN: catscratch disease.
leukemic r. obsolete term for monocytic leukemia.
malignant midline r. obsolete term for polymorphic r.
midline malignant r. granuloma SYN: lethal midline granuloma.
pagetoid r. a usually solitary verrucous plaque on the extremities characterized histologically by predominantly epidermal infiltration of mononuclear cells resembling those found in mycosis fungoides; prognosis is good. SYN: Woringer-Kolopp disease.
polymorphic r. a necrotizing lymphoproliferative lesion with a predilection for the upper respiratory tract; previously called lethal midline granuloma or malignant midline r.; treatment is irradiation.

reticulospinal
reticulospinal (re-tik-u-lo-spi′nal)

Pertaining to the r. tract.

reticulotomy
reticulotomy (re-tik-u-lot′o-me)

Production of lesions in the reticular formation. [reticulo- + G. tome, incision]

reticulum
reticulum, pl .reticula (re-tik′u-lum, -la) [TA]

1. A fine network formed by cells, or formed of certain structures within cells or of connective tissue fibers between cells. 2. SYN: neuroglia. 3. The second compartment of the stomach of a ruminant, a comparatively small chamber communicating with the rumen; sometimes called the honeycomb because of the characteristic structure of its wall. [L. dim of rete, a net]
agranular endoplasmic r. endoplasmic r. that is lacking in ribosomal granules; involved in synthesis of complex lipids and fatty acids, detoxification of drugs, carbohydrate synthesis, and sequestering of Ca⁺⁺. SYN: smooth-surfaced endoplasmic r..
Ebner r. a network of nucleated cells in the seminiferous tubules.
endoplasmic r. (ER) the network of cytoplasmic tubules or flattened sacs (cisternae) with (rough ER) or without (smooth ER) ribosomes on the surface of their membranes in eukaryotes. SYN: endomembrane system.
Golgi internal r. SYN: Golgi apparatus.
granular endoplasmic r. endoplasmic r. in which ribosomal granules are applied to the cytoplasmic surface of the cisternae; involved in the synthesis and secretion of protein via membrane-bound vesicles to the extracellular space. SYN: chromidial substance, ergastoplasm, rough-surfaced endoplasmic r..
Kölliker r. SYN: neuroglia.
rough-surfaced endoplasmic r. SYN: granular endoplasmic r..
sarcoplasmic r. the endoplasmic r. of skeletal and cardiac muscle; the complex of vesicles, tubules, and cisternae forming a continuous structure around striated myofibrils, with a repetition of structure within each sarcomere.
smooth-surfaced endoplasmic r. SYN: agranular endoplasmic r..
stellate r. a network of epithelial cells disposed in a fluid-filled compartment in the center of the enamel organ between the outer and inner enamel epithelium.
trabecular r. SYN: trabecular tissue of sclera.
r. trabeculare sclerae [TA] SYN: trabecular tissue of sclera.
trans-Golgi r. that part of the Golgi apparatus that takes newly processed proteins and delivers them to secretory vesicles that will fuse with other biomembranes ( E.G., the plasma membrane).

retiform
retiform (ret′i-form)

Resembling a net or network. [L. rete, network]

retin- retin-

See retino-.

retina
retina (ret′i-na) [TA]

Grossly, the r. consists of three parts: optic part of r., ciliary part of r., and iridial part of r.. The optic part, the physiologic portion that receives the visual light rays, is further divided into two parts, the pigmented part (pigment epithelium) and the nervous part, which are arranged in the following layers: 1) pigmented layer; 2) layer of inner and outer segments (of rods and cones); 3) outer limiting layer (actually a row of junctional complexes); 4) outer nuclear layer; 5) outer plexiform layer; 6) inner nuclear layer; 7) inner plexiform layer; 8) ganglionic (cell) layer; 9) layer of nerve fibers; and 10) inner limiting layer. Layers 2–10 compose the neural layer. At the posterior pole of the visual axis is the macula, in the center of which is the fovea, the area of acute vision. Here layers 6–9 and blood vessels are absent, and only elongated cones are present. About 3 mm medial to the fovea is the optic disk, where axons of the ganglionic cells converge to form the optic nerve. The ciliary and iridial parts of the r. are forward prolongations of the pigmented layer and a layer of supporting columnar or epithelial cells over the ciliary body and the posterior surface of the iris, respectively. SYN: optomeninx. [Mediev. L. prob. fr. L. rete, a net]
detached r. SYN: retinal detachment.
flecked r. an r. exhibiting fundus flavimaculatus, hereditary drusen, or fundus albipunctatus.
fleck r. of Kandori [MIM*228990] an autosomal recessive disorder of the retinal pigment epithelium characterized by retinal flecks and night blindness, occurring among Japanese.
leopard r. SYN: tessellated fundus.
shot-silk r. the appearance of numerous wavelike, glistening reflexes, like the shimmer of silk, observed sometimes in the r. of a young person. SYN: shot-silk phenomenon, shot-silk reflex.
tigroid r. SYN: tessellated fundus.

retinaculum
retinaculum, gen. retinaculi, pl .retinacula (ret-i-nak′u-lum, -li, -la) [TA]

A frenum, or a retaining band or ligament. [L. a band, a halter, fr. retineo, to hold back]
antebrachial flexor r. thickening of distal antebrachial fascia just proximal to radiocarpal (wrist) joint. Continuous with extensor r. at margins of forearm. This structure is distinct from the transverse carpal ligament, commonly called “the flexor r.,” which forms the roof of the carpal tunnel. SYN: flexor r. of forearm, palmar carpal ligament.
r. of articular capsule of hip one of several longitudinal folds of the articular capsule of the hip joint reflected onto the femoral neck deep to which the retinacular branches of the medial femoral circumflex artery pass to reach the femoral head. SYN: r. capsulae articularis coxae, Weitbrecht fibers.
r. capsulae articularis coxae SYN: r. of articular capsule of hip.
caudal r. SYN: r. caudale.
r. caudale [TA] fibrous bands, remnants of the notochord, that extend from the skin to the coccyx, forming the coccygeal foveola. SYN: caudal ligament, caudal r., ligamentum caudale.
r. cutis [TA] SYN: skin ligaments, under ligament.
r. cutis mammae suspensory ligaments of breast, under ligament.
extensor r. [TA] a strong fibrous band formed as a thickening of the antebrachial deep fascia, stretching obliquely across the back of the wrist, attaching deeply to ridges on the dorsal aspect of the radius, triquetral, and pisiform bones, and binding down the extensor tendons of the fingers and thumb. SYN: r. musculorum extensorum [TA] , dorsal carpal ligament, ligamentum carpi dorsale.
retinacula of extensor muscles See inferior extensor r., superior extensor r..
flexor r. [TA] a strong fibrous band crossing the front of the carpus and binding down the flexor tendons of the digits and the flexor carpi radialis tendon and the median nerve; in so doing it creates the carpal tunnel. SYN: r. musculorum flexorum [TA] , deep part of flexor r., ligamentum carpi transversum, ligamentum carpi volare, transverse carpal ligament, volar carpal ligament.
flexor r. of forearm SYN: antebrachial flexor r..
flexor r. of lower limb [TA] a wide band passing from the medial malleolus to the medial and upper border of the calcaneus and to the plantar surface as far as the navicular bone; it holds in place the tendons of the tibialis posterior, flexor digitorum longus, and flexor hallucis longus. SYN: r. musculorum flexorum membri inferioris [TA] , laciniate ligament, ligamentum laciniatum, r. of flexor muscles.
r. of flexor muscles SYN: flexor r. of lower limb.
inferior extensor r. [TA] a Y-shaped ligament restraining the extensor tendons of the foot distal to the ankle joint. SYN: r. musculorum extensorum inferius [TA] , cruciate ligament of leg, inferior r. of extensor muscles, ligamentum cruciatum cruris.
inferior r. of extensor muscles SYN: inferior extensor r..
inferior fibular r. [TA] broad thickened band of deep fascia overlying fibularis longus and brevis tendons as they pass along the lateral margin of the foot, anchoring the tendons and their associated bursae in place; it is a lateral continuation of the stem of the Y-shaped inferior extensor r. which attaches to the fibular trochlea of the calcaneus (which intervenes between the two tendons) and then continues to attach to the inferolateral aspect of the calcaneous. SYN: r. musculorum fibularium inferius [TA] , inferior peroneal r.&star, r. musculorum peroneorum inferius&star.
inferior peroneal r. inferior fibular r..
lateral patellar r. [TA] part of the aponeurosis of the vastus lateralis muscle passing lateral to the patella to attach to the tibial tuberosity. SYN: r. patellae laterale [TA] .
medial patellar r. [TA] part of the aponeurosis of the vastus medialis muscle passing medial to the patella to attach to the medial condyle of the tibia, forming the anteromedial aspect of the fibrous capsule of the knee joint. SYN: r. patellae mediale [TA] .
Morgagni r. SYN: frenulum of ileal orifice.
r. musculorum extensorum [TA] SYN: extensor r..
r. musculorum extensorum inferius [TA] SYN: inferior extensor r..
r. musculorum extensorum superius [TA] SYN: superior extensor r..
r. musculorum fibularium SYN: peroneal r..
r. musculorum fibularium inferius [TA] SYN: inferior fibular r..
r. musculorum fibularium superius [TA] SYN: superior fibular r..
r. musculorum flexorum [TA] SYN: flexor r..
r. musculorum flexorum membri inferioris [TA] SYN: flexor r. of lower limb.
r. musculorum peroneorum SYN: peroneal r..
retinacula of nail fibrous attachments of the nail-bed to the underlying phalanx. SYN: retinacula unguis.
r. patellae laterale [TA] SYN: lateral patellar r..
r. patellae mediale [TA] SYN: medial patellar r..
patellar r. extensions of the aponeuroses of the vasti medialis and lateralis muscles that pass on each side of the patella, attaching to the margins of the patella and patellar ligament anteriorly, the collateral ligaments posteriorly, and the tibial condyles distally; form the anteromedial and (with the fibrous expansion of the iliotibial tract) the anteromedial portions of the fibrous capsule of the knee. See lateral patellar r., medial patellar r..
peroneal r. superior and inferior fibrous bands retaining the tendons of the peroneus longus and brevis in position as they cross the lateral side of the ankle. SYN: retinacula of peroneal muscles, r. musculorum fibularium, r. musculorum peroneorum.
r. musculorum peroneorum inferius inferior fibular r..
r. musculorum peroneorum superius superior fibular r..
retinacula of peroneal muscles SYN: peroneal r..
r. of skin SYN: skin ligaments, under ligament.
superior extensor r. [TA] the ligament that binds down the extensor tendons proximal to the ankle joint; it is continuous with (a thickening of) the deep fascia of the leg. SYN: r. musculorum extensorum superius [TA] , ligamentum transversum cruris, superior r. of extensor muscles, transverse crural ligament, transverse ligament of leg.
superior r. of extensor muscles SYN: superior extensor r..
superior fibular r. [TA] SYN: r. musculorum fibularium superius [TA] , r. musculorum peroneorum superius&star, superior peroneal r.&star.
superior peroneal r. superior fibular r..
suspensory r. of breast suspensory ligaments of breast, under ligament.
r. tendinum a ligamentous structure to restrain tendons, such as the flexor or extensor retinacula, or the annular parts of the digital fibrous sheaths.
retinacula unguis SYN: retinacula of nail.

retinal
retinal (ret′i-nal)

1. Relating to the retina. 2. Retinaldehyde; most commonly referring to the all-trans form.
r. dehydrogenase an oxidoreductase catalyzing the interconversion of retinaldehyde and NAD⁺ to retinoic acid and NADH, thus affecting growth and differentiation. SYN: retinaldehyde dehydrogenase.
r. isomerase an isomerase that catalyzes the cis-trans-interconversion of all-trans-r. to 11-cis-r.(dehyde); a part of the vision cycle. SYN: retinaldehyde isomerase.
r. reductase alcohol dehydrogenase (NAD(P)⁺).

retinaldehyde
retinaldehyde (ret-i-nal′de-hid)

Retinol oxidized to a terminal aldehyde; retinal; a carotene released (as all-trans-retinal) in the bleaching of rhodopsin by light and the dissociation of opsin in the vision cycle. SYN: retinene-1, retinene, vitamin A aldehyde.
r. dehydrogenase SYN: retinal dehydrogenase.
r. isomerase SYN: retinal isomerase.
r. reductase alcohol dehydrogenase (NAD(P)⁺).

retinectomy
retinectomy (ret′in-ek′to-me)

A surgical excision of a piece of the retina.

retinene
retinene (ret′i-nen)

SYN: retinaldehyde.

retinene-1
retinene-1

SYN: retinaldehyde.

retinene-2
retinene-2

SYN: dehydroretinaldehyde.

retinitis
retinitis (ret-i-ni′tis)

Inflammation of the retina. [retina + G. -itis, inflammation]
albuminuric r. hypertensive retinopathy.
circinate r. circinate retinopathy.
diabetic r. diabetic retinopathy.
exudative r., r. exudativa a chronic abnormality characterized by deposition of cholesterol and cholesterol esters in outer retinal layers and subretinal space. In adults, often preceded by uveitis; in children, often preceded by retinal vascular abnormalities. SYN: Coats disease.
leukemic r. leukemic retinopathy.
metastatic r. purulent or septic r. resulting from the arrest of septic emboli in the retinal vessels. SYN: purulent r., septic r..
r. pigmentosa a progressive retinal degeneration characterized by bilateral nyctalopia, constricted visual fields, electroretinogram abnormalities, and pigmentary infiltration of the inner retinal layers; may be sporadic or demonstrate autosomal dominant [MIM*180100], autosomal recessive, or X-linked inheritance [MIM*268000, *312600, *312610]. SYN: pigmentary retinopathy.
r. proliferans SYN: proliferative retinopathy.
punctate r. retinopathy punctata albescens.
purulent r. SYN: metastatic r..
r. sclopetaria a severe contusion lesion of the retina, as from a shot pellet or BB. [from sclopetum, a medieval handgun]
secondary r. r. that follows uveal inflammation.
septic r. SYN: metastatic r..
serous r. edema of the retina; an inflammation of the inner layers of the retina. SYN: simple r..
simple r. SYN: serous r..
r. syphilitica, syphilitic r. r. often associated with syphilitic choroiditis, especially in congenital syphilis.

retino- retino-, retin-

The retina. [Med. L. retina]

retinoblastoma
retinoblastoma (ret′i-no-blas-to′ma) [MIM*180200, MIM*180201, MIM*180202]

Malignant ocular neoplasm of childhood, with onset usually before the third year of life, composed of primitive retinal small round cells with deeply staining nuclei and elongated cells forming rosettes; there is an increased risk of developing osteosarcoma later in life. In familial cases, the disease is usually bilateral with multiple lesions within an eye, but in sporadic cases rarely so. Autosomal dominant inheritance caused by mutation in the tumor-suppressor r. gene (RB) on chromosome 13q. [retino- + G. blastos, germ, + -oma, tumor]

retinochoroid
retinochoroid (ret′i-no-ko′royd)

SYN: chorioretinal.

retinochoroiditis
retinochoroiditis (ret′i-no-ko-roy-di′tis)

Inflammation of the retina extending to the choroid. SYN: chorioretinitis. [retinochoroid + G. -itis, inflammation]
bird shot r. bilateral diffuse retinal vasculitis with depigmentation of multiple areas of the choroid and retinal pigment epithelium posterior to the ocular equator, often with an associated papillitis or optic atrophy; vitiligo occurs occasionally. SYN: vitiliginous choroiditis.
r. juxtapapillaris r. close to the optic disk. SYN: Jensen disease.

retinodialysis
retinodialysis (ret′i-no-di-al′i-sis)

SYN: dialysis retinae. [retino- + G. dialysis, separation]

retinoic acid
retinoic acid (ret-i-no′ik)

Vitamin A₁ acid;retinal in which the terminal –CHO has been oxidized to a –COOH; used topically in the treatment of acne; plays an important role in growth and differentiation. SYN: vitamin A₁ acid.
13-cis-r. the retinoid most used in the U.S. to treat acne; it works by reducing sebum secretion. Use in pregnancy is contraindicated because of teratogenicity.

retinoid
retinoid (ret′i-noyd)

1. Resembling a resin; resinous. [G. retine, resin, + eidos, resemblance] 2. Resembling the retina. [Mediev. L. retina] 3. In plural form, term used to describe the natural forms and synthetic analogs of retinol.

retinoids
retinoids (ret′i-noydz)

A class of keratolytic drugs derived from retinoic acid and used for treatment of severe acne and psoriasis.

retinol
retinol (ret′i-nol)

A half-carotene bearing the β (or β-ionone) form of the cyclic end group and a CH₂OH at the C-15 position (numbering as in carotenoids) or 9′-position (numbering as a nonyl side chain on a cyclohexene ring); an intermediate in the vision cycle, it also plays a role in growth and differentiation. SEE ALSO: dehydroretinol. SYN: vitamin A₁ alcohol, vitamin A₁.
r. dehydrogenase an oxidoreductase catalyzing interconversion of retinal and NADH to r. and NAD⁺.

retinopapillitis
retinopapillitis (ret′i-no-pap-i-li′tis)

Inflammation of the retina extending to the optic disk.
r. of premature infants SYN: retinopathy of prematurity.

retinopathy
retinopathy (ret-i-nop′a-the)

Noninflammatory degenerative disease of the retina. [retino- + G. pathos, suffering]
arteriosclerotic r. r. distinguished by attenuated retinal arterioles with increased tortuosity, copper- or silver-wire appearance, perivascular sheathing, irregularity of lumen and scattered small hemorrhages, and small, sharp-edged deposits without surrounding edema.
central angiospastic r. SYN: central serous choroidopathy.
central serous r. SYN: central serous choroidopathy.
circinate r. a retinal degeneration marked by a girdle of sharply defined white exudates around an edematous macula; usually bilateral and typically affects the aged.
compression r. 1. See Berlin edema. See traumatic r..
diabetic r. retinal changes occurring in diabetes mellitus, marked by microaneurysms, exudates, and hemorrhages, and sometimes by neovascularization. SYN: fundus diabeticus.Diabetic eye disease is responsible for approximately 25% of all newly reported cases of blindness in the U.S. The principal form is nonproliferative r., which results directly from degenerative changes in retinal capillaries. Features of this disorder, as observed on funduscopic examination, include microaneurysms; soft or cotton-wool exudates, which are actually areas of microinfarction; hard or waxy exudates, which are deposits of lipid and protein from leaking capillaries; and flame hemorrhages. A few patients, principally those with type 1 diabetes, develop a proliferative r. characterized by neovascularization (proliferation of new capillary loops on the retinal surface). Either type of r. can impair vision by destroying retinal tissue directly and by predisposing to retinal edema, retinal detachment, and vitreous hemorrhage. Controlled clinical studies have shown that maintaining blood glucose levels as near as possible to normal at all times in persons with diabetes mellitus substantially retards the onset and rate of progression of r.. Laser photocoagulation is effective in arresting neovascularization in proliferative diabetic r..
dysproteinemic r. retinal venous congestion due to increased blood viscosity in dysproteinemia.
electric r. SYN: photoretinopathy.
external exudative r. exudative retinitis.
hypertensive r. a retinal condition occurring in accelerated vascular hypertension, marked by arteriolar constriction, flame-shaped hemorrhages, cotton-wool patches, star-figure edema at the macula, and papilledema.
Leber idiopathic stellate r. See neuroretinitis.
leukemic r. appearance of the retina in all types of leukemia, characterized by engorgement and tortuosity of veins, scattered hemorrhages, and edema of the retina and disk.
lipemic r. a milkiness of the retinal vessels (lipemia retinalis) combined with hard-edged fatty exudates, seen in patients with diabetic acidosis and hyperlipemia.
macular r. SYN: maculopathy.
pigmentary r. SYN: retinitis pigmentosa.
r. of prematurity abnormal replacement of the sensory retina by fibrous tissue and blood vessels, occurring mainly in premature infants having a birth weight of less than 1500 g who are placed in a high-oxygen environment. SYN: retinopapillitis of premature infants, retrolental fibroplasia, Terry syndrome.
proliferative r. neovascularization of the retina extending into the vitreous humor. SYN: retinitis proliferans.
r. punctata albescens [MIM*136880] a disease in which both fundi show numerous white dots or flecks through the retinae, causing night blindness; autosomal dominant inheritance, caused by mutation in the “retinal degeneration, slow” gene (RDS) encoding peripherin on chromosome 6p. There is also a recessive form [MIM*210370].
Purtscher r. transient traumatic retinal angiopathy due to a sudden rise in venous pressure, as in compression of the body from seat belt injury; ocular fundi show large white patches associated with the retinal veins about the disk or macula, hemorrhages, and retinal edema; thought to be due to fat embolism from bone marrow. SYN: Purtscher disease, transient r., traumatic r..
renal r. hypertensive r. associated with chronic glomerulonephritis or nephrosclerosis.
rubella r. peripheral pigmentary retinal changes in congenital rubella, not affecting visual function.
sickle cell r. a condition marked by dilation and tortuosity of retinal veins and by microaneurysms and retinal hemorrhages; advanced stages may show neovascularization, vitreous hemorrhage, or retinal detachment.
solar r. SYN: photoretinopathy.
toxemic r. of pregnancy sudden angiospasm of retinal arterioles, later followed by retinal vascular signs of advanced hypertensive r.; vascular changes disappear rapidly after termination of the pregnancy.
toxic r. retinal changes due to prolonged administration of various drugs.
transient r. SYN: Purtscher r..
traumatic r. SYN: Purtscher r..
venous-stasis r. a uniocular r. associated with occlusion of the central retinal vein; a nonischemic central retinal vein occlusion.
whiplash r. an injury to the retina caused by a sudden acceleration/deceleration injury.

retinopexy
retinopexy (ret′i-no-pek′se)

A procedure to repair a detached retina by holding it in place; e.g., by producing chorioretinal adhesions by freezing (“retinal cryopexy”). [retino- + G. pexis, fixation]
fluid r. a procedure to repair a detached retina by holding it in place with a fluid that is heavier than vitreous fluid.
gas r. a retinal detachment repair in which the retina is held in place by an expandable gas. SYN: pneumatic r..
pneumatic r. SYN: gas r..

retinopiesis
retinopiesis (ret′i-no-pi-e′sis)

Repositioning a detached retina by pressing it into position by gas or fluid. See retinopexy. [retino- + G. piesis, pressure]

retinoschisis
retinoschisis (ret-i-nos′ki-sis)

Degenerative splitting of the retina, with cyst formation between the two layers. [retino- + G. schisis, division]
juvenile r. [MIM*268100] r. occurring before 10 years of age and within the nerve-fiber layer, with frequent macular involvement; at first, the inner wall is a translucent veil-like membrane, but it becomes more dense and may render the retina white; autosomal recessive inheritance. There is a form of this condition in middle age that is X-linked [MIM*312700] and a rare autosomal dominant form [MIM*180270].
senile r. r. occurring most often in the elderly and affecting the outer plexiform layer; it begins in the extreme inferotemporal periphery and is not significantly progressive; vision usually is good.

retinoscope
retinoscope (ret′i-no-skop)

An optical device used to illuminate a subject's retina during retinoscopy. [retino- + G. skopeo, to view]
luminous r. a portable optical device providing either a circular or linear (streak) beam of light.
reflecting r. a plane or concave mirror with a central perforation that allows the observer to see rays emerge from the subject's eye.

retinoscopy
retinoscopy (ret′i-nos′ko-pe)

A method of determining errors of refraction by illuminating the retina and observing the rays of light emerging from the eye. SYN: scotoscopy, shadow test, skiascopy. [retino- + G. skopeo, to view]
cylinder r. determination of spherical, astigmatic, and refractive error using cylindric lenses.
fogging r. the method of reducing vision with convex lenses until accommodation is suspended; a static, noncycloplegic technique.

retinotomy
retinotomy (ret′in-ot′o-me)

A surgical incision through the retina.

retinyl phosphate
retinyl phosphate (ret′i-nil fos′fat)

The phosphoester of all-trans-retinol; essential for the biosynthesis of certain glycoproteins needed for growth regulation and for mucous secretion.

retoperithelium
retoperithelium (re′to-per-i-the′le-um)

The reticular cells related to the reticular fiber network, as in the stroma of lymphatic tissue. [L. rete, net, + G. peri, around, + Mod. L. thelium, fr. G. thele, nipple]

retort
retort (re-tort′)

1. A flasklike vessel with a long neck passing outward, once used in distilling. 2. A small furnace. [Mediev. L. retorta, fem. pp. of retorqueo, pp. -tortus, to twist or bend back]

Retortamonas
Retortamonas (re-tor-tam′o-nas)

A genus of protozoan flagellates, one species of which, R. intestinalis, is found occasionally in the human intestine, although it is nonpathogenic and infrequently reported. [L. re-torqueo, to twist back, + G. monas, single, a unit]

retract
retract (re-trakt′)

To shrink, draw back, or pull apart. [L. re-traho, pp. -tractus, a drawing back]

retractile
retractile (re-trak′til)

Retractable; capable of being drawn back.

retraction
retraction (re-trak′shun)

1. A shrinking, drawing back, or pulling apart. 2. Posterior movement of teeth, usually with the aid of an orthodontic appliance. [L. retractio, a drawing back]
gingival r. 1. lateral movement of the gingival margin away from the tooth surface; may be indicative of underlying inflammation or pocket formation; 2. displacement of the marginal gingivae away from the tooth by mechanical, chemical, or surgical means.
mandibular r. a type of facial anomaly in which the gnathion lies posterior to the orbital plane.

retractor
retractor (re-trak′ter, -tor)

1. An instrument for drawing aside the edges of a wound or for holding back structures adjacent to the operative field. 2. A muscle that draws a part backward, e.g., the middle part of the trapezius muscle is a r. of the scapula; the horizontal fibers of the temporalis muscle serve to retract the mandible.
Desmarres r. an instrument used to withdraw an eyelid.

retrad
retrad (re′trad)

Backward; toward the back part; directed posteriorly. [L. retro, backward, + ad, to]

retrahens aurem
retrahens aurem, retrahens auriculam (ret′ra-henz aw′rem, aw-rik′u-lam)

See auricularis posterior (muscle). [L. drawing back the ear, or auricle]

retreat from reality
retreat from reality

Substitution of imaginary satisfactions or fantasy for relations with the real world.

retrenchment
retrenchment (re-trench′-ment)

The cutting away of superfluous tissue. [F. re-, back, + trancher, to cut]

retrieval
retrieval (re-tre′val)

The third stage in the memory process, after encoding and storage, involving mental processes associated with bringing stored information back into consciousness. SEE ALSO: memory.

retro- retro-

Backward or behind. [L. back, backward]

retroauricular
retroauricular (re′tro-aw-rik′u-lar)

Behind the auricle.

retrobuccal
retrobuccal (re′tro-buk′al)

Relating to the back part of, or behind, the cheek.

retrobulbar
retrobulbar (re′tro-bul′bar)

Behind the eyeball. SYN: retro-ocular.

retrocalcaneobursitis
retrocalcaneobursitis (re′tro-kal-ka′ne-o-ber-si′tis)

SYN: achillobursitis. [retro- + L. calcaneum heel, + bursitis]

retrocecal
retrocecal (re′tro-se′kal)

Posterior to the cecum.

retrocervical
retrocervical (re′tro-ser′vi-kal)

Posterior to the cervix uteri.

retrocession
retrocession (re-tro-sesh′un)

1. A going back; a relapse. 2. Cessation of the external symptoms of a disease followed by signs of involvement of some internal organ or part. 3. Denoting a position of the uterus or other organ farther back than is normal. [L. retro-cedo, pp. -cessus, to go back, retire]

retroclusion
retroclusion (re-tro-kloo′zhun)

A form of acupressure for the arrest of bleeding; the needle is passed through the tissues above the cut end of the artery, is turned around, and then is passed backward beneath the vessel to come out near the point of entrance. [retro- + L. claudo (cludo) to close]

retrocolic
retrocolic (re′tro-kol′ik)

Posterior to the colon. [retro- + G. kolon, colon]

retrocollic
retrocollic (re′tro-kol′ik)

Relating to the back of the neck; drawing back the head. [retro- + L. collum, neck]

retroconduction
retroconduction (re-tro-kon-duk′shun)

SYN: retrograde VA conduction.

retrocursive
retrocursive (re′tro-ker′siv)

Running backward. [retro- + L. cursus, a running]

retrodeviation
retrodeviation (re′tro-de-ve-a′shun)

A backward bending or inclining.

retrodisplacement
retrodisplacement (re′tro-dis-plas′ment)

Any backward displacement, such as retroversion or retroflexion of the uterus.

retroesophageal
retroesophageal (re′tro-e-sof′a-je′al)

Posterior to the esophagus.

retrofilling
retrofilling (re-tro-fil′ing)

Placement of a sealing material into the apical foramen of a dental root from the apical end.

retroflected
retroflected (re′tro-flek-ted)

SYN: retroflexed.

retroflection
retroflection (re-tro-flek′shun)

SYN: retroflexion.

retroflexed
retroflexed (re′tro-flekst)

Bent backward or posteriorly. SYN: retroflected. [retro- + L. flecto, pp. flexus, to bend]

retroflexion
retroflexion (re-tro-flek′shun)

Backward bending, as of the uterus when the corpus is bent back, forming an angle with the cervix. SYN: retroflection.
r. of iris abnormal position of the iris on the ciliary body after severe concussion.

retrognathic
retrognathic (re-tro-nath′ik)

Denoting a state in which the mandible is located posterior to its normal position in relation to the maxillae.

retrognathism
retrognathism (re-tro-nath′izm)

A condition of facial disharmony in which one or both jaws are posterior to normal in their craniofacial relationships; usually used in reference to the mandible. [retro- + G. gnathos, jaw]

retrograde
retrograde (ret′ro-grad)

1. Moving backward. 2. Degenerating; reversing the normal order of growth and development. [L. retrogradus, fr. retro- + gradior, to go]

retrography
retrography (re-trog′ra-fe)

SYN: mirror-writing. [retro- + G. grapho, to write]

retrogression
retrogression (re-tro-gresh′un)

SYN: cataplasia. [L. retrogressus fr. retrogradior, to go backwards]

retroinhibition
retroinhibition (re′tro-in-hi-bish′un)

SYN: feedback inhibition.

retroiridian
retroiridian (re′tro-i-rid′e-an)

Posterior to the iris.

retrojection
retrojection (re-tro-jek′shun)

The washing out of a cavity by the backward flow of an injected fluid. [L. retro, backward, + jacio, to throw]

retrojector
retrojector (re′tro-jek-ter, -tor)

A form of syringe with long tubular attachment to the nozzle, used in retrojection.

retrolental
retrolental (re′tro-len′tal)

Posterior to the lens of the eye. SYN: retrolenticular (1) .

retrolenticular
retrolenticular (re′tro-len-tik′u-lar)

1. SYN: retrolental. 2. Behind the lentiform nucleus of the brain.

retrolingual
retrolingual (re′tro-ling′gwal)

Relating to the back part of the tongue; posterior to the tongue. [retro- + L. lingua, tongue]

retromammary
retromammary (re′tro-mam′a-re)

Posterior to the mamma.

retromandibular
retromandibular (re′tro-man-dib′u-lar)

Posterior to the lower jaw. [retro- + L. mandibula, lower jaw]

retromastoid
retromastoid (re′tro-mas′toyd)

Posterior to the mastoid process; relating to the posterior mastoid cells.

retromolar
retromolar (re-tro-mo′lar)

Distal (or posterior) to the last erupted (or present) molar tooth.

retromorphosis
retromorphosis (re-tro-mor′fo-sis, -mor-fo′sis)

SYN: cataplasia. [retro- + G. morphosis, process of forming]

retronasal
retronasal (re′tro-na′zal)

Posterior nasal; relating to the posterior nares.

retro-ocular
retro-ocular (re′tro-ok′u-lar)

SYN: retrobulbar.

retroperitoneal
retroperitoneal (re′tro-per′i-to-ne′al)

External or posterior to the peritoneum.

retroperitoneum
retroperitoneum (re′tro-per′i-to-ne′um)

SYN: retroperitoneal space. [retro- + peritoneum]

retroperitonitis
retroperitonitis (ret′ro-per-i-to-ni′tis)

Inflammation of the cellular tissue behind the peritoneum.
idiopathic fibrous r. SYN: retroperitoneal fibrosis.

retropharyngeal
retropharyngeal (re′tro-fa-rin′je-al)

Posterior to the pharynx.

retropharynx
retropharynx (re′tro-far′ingks)

The posterior part of the pharynx.

retroplacental
retroplacental (re′tro-pla-sen′tal)

Behind the placenta.

retroplasia
retroplasia (ret-ro-pla′ze-a)

That state of cell or tissue in which activity is decreased below that considered normal; associated with retrogressive changes ( e.g., injury, degeneration, death, necrosis). [retro- + G. plasis, a molding]

retroposed
retroposed (re′tro-pozd)

Denoting retroposition. [retro- + L. pono, pp. positus, to place]

retroposition
retroposition (re′tro-po-zish′un)

Simple backward displacement of a structure or organ, as the uterus, without inclination, bending, retroversion, or retroflexion. [retro- + L. positio, a placing]

retroposon
retroposon (re-tro-pos′on)

A transposition of sequences in a DNA that does not originate in the DNA but rather in an mRNA that is transcribed back into the genomic DNA by reverse transcription. [retro- + L. pono, pp. positum, to place, + -on]

retropubic
retropubic (re-tro-pu′bik)

Posterior to the pubic bone.

retropulsion
retropulsion (re-tro-pul′shun)

1. An involuntary backward walking or running, occurring in patients with the parkinsonian syndrome. 2. A pushing back of any part. [retro- + L. pulsio, a pushing, fr. pello, pp. pulsus, beat, drive]

retrospection
retrospection (re-tro-spek′shun)

The act or process of surveying and reviewing the past. [retro- + L. specto, pp. spectatus, to look at]

retrospective
retrospective (re-tro-spek′tiv)

Relating to retrospection.

retrospondylolisthesis
retrospondylolisthesis (re′tro-spon′di-lo-lis-the′sis)

Slipping posteriorly of the body of a vertebra, bringing it out of line with the adjacent vertebrae. [retro- + G. spondylos, vertebra, + olisthesis, a slipping]

retrosternal
retrosternal (re′tro-ster′nal)

Posterior to the sternum.

retrosteroid
retrosteroid (re-tro-ster′oyd, -ster′oyd)

A term sometimes used to designate a steroid in which the orientations of the substituents at carbons-9 and -10 are the opposite of those of the reference or “parent” compound.

retrotarsal
retrotarsal (re′tro-tar′sal)

Posterior to the tarsus, or edge of the eyelid.

retrouterine
retrouterine (re′tro-u′ter-in)

Posterior to the uterus.

retroversioflexion
retroversioflexion (re-tro-ver′se-o-flek′shun, -ver′zho-)

Combined retroversion and retroflexion of the uterus.

retroversion
retroversion (re-tro-ver′zhun)

1. A turning backward, as of the uterus. 2. Condition in which the teeth are located in a more posterior position than is normal. [retro- + L. verto, pp. versus, to turn]

retroverted
retroverted (re′tro-ver-ted)

Denoting retroversion.

Retroviridae
Retroviridae (re-tro-vir′i-de)

A family of RNA viruses 80–100 nm in diameter, enveloped, and containing two identical molecules of positive sense, single-stranded RNA, molecular weight 3–6 × 10⁶; genomic RNA serves as a template for the synthesis of a complementary DNA, which may be integrated into the host DNA. There are currently 7 genera: Mammalian type B retroviruses, Mammalian type C retroviruses, Avian type C retroviruses, Type D retroviruses, BLV-HTLV retroviruses, Lentivirus, and Spumovirus.

retrovirus
retrovirus (re′tro-vi′rus)

Any virus of the family Retroviridae.Retroviruses are potent disease agents, but they have also served as invaluable research tools in molecular biology. In 1979, the molecular biologist Richard Mulligan used a genetically altered r. to trigger the production of hemoglobin in vitro by monkey kidney cells. His technique for using retroviruses to import alien genes into cells has been widely adopted. Medical researchers have also explored retroviral transport as a means of gene therapy. However, evidence suggesting that retroviruses may play a role in carcinogenesis raises questions as to the safety of their use in gene therapy. See oncogene.

retrusion
retrusion (re-troo′zhun)

1. Retraction of the mandible from any given point. 2. The backward movement of the mandible. [L. retrudo, pp. -trusus, to push back]

Rett
Rett

Andreas, 20th century Austrian pediatrician. See R. syndrome.

return
return

total anomalous pulmonary venous r. (TAPVR) See anomalous pulmonary venous connections, total or partial, under connection.
venous r. the blood returning to the heart via the great veins and coronary sinus.

Retzius
Retzius

Magnus G., Swedish anatomist and anthropologist, 1842–1919. See R. striae, under stria, lines of R., under line, foramen of R., calcification lines of R., under line, foramen of Key-R., sheath of Key and R..

Retzius
Retzius

Anders A., Swedish anatomist and anthropologist, 1796–1860. See R. cavity, cavum retzii, R. fibers, under fiber, R. gyrus, R. ligament, R. space, retroperitoneal veins, under vein.

reunient
reunient (re-u′ne-ent)

Connecting; denoting the ductus reuniens. [L. re-, again, + unio, pp. unitus, to unite]

Reuss
Reuss

August von, Austrian ophthalmologist, 1841–1924. See R. formula, R. test.

revaccination
revaccination (re′vak-si-na′shun)

Vaccination of an individual previously successfully vaccinated.

revascularization
revascularization (re-vas′ku-lar-i-za′shun)

Reestablishment of blood supply to a part.

reverberation
reverberation (re′ver-be-ra′shun)

Multiple echoes or reflections; in ultrasonography, an artifactual image caused by delay of an echo that has been reflected back and forward again before returning to the transducer.

Reverdin
Reverdin

Jacques L., Swiss surgeon, 1842–1929. See R. graft.

reversal
reversal (re-ver′sal)

1. A turning or changing to the opposite direction, as of a process, disease, symptom, or state. 2. The changing of a dark line or a bright one of the spectrum into its opposite. 3. Denoting the difficulty of some persons in distinguishing the lowercase printed or written letter p from q or g, b from d, or s from z. 4. In psychoanalysis, the change of an instinct or affect into its opposite, as from love into hate. [L. reverto, pp. -versus, to turn back or about]
adrenaline r. SYN: epinephrine r..
epinephrine r. the fall in blood pressure produced by epinephrine when given following blockage of α-adrenergic receptors by an appropriate drug such as phenoxybenzamine; the vasodilation reflects the ability of epinephrine to activate β-adrenergic receptors that, in vascular smooth muscle, are inhibitory; in the absence of α-receptor blockade, the β-receptor activation by epinephrine is masked by its predominant action on vascular α-receptors, which causes vasoconstriction. SYN: adrenaline r..
narcotic r. the use of narcotic antagonists, such as naloxone, to terminate the action of narcotics.
pressure r. cessation of anesthesia by hyperbaric pressure; of major importance in understanding the mode of action of anesthetics.
sex r. SYN: sex reassignment.

reversible
reversible (re-ver′si-bl)

Capable of reversal; said of diseases or chemical reactions.

reversion
reversion (re-ver′zhun)

1. The manifestation in an individual of certain characteristics, peculiar to a remote ancestor, which have been suppressed during one or more of the intermediate generations. 2. The return to the original phenotype, either by reinstatement of the original genotype (true r.) or by a mutation at a site different from that of the first mutation, which cancels the effect of the first mutation (suppressor mutation). [L. reversio (see reversal)]

revertant
revertant (re-ver′tant)

In microbial genetics, a mutant that has reverted to its former genotype (true reversion) or to the original phenotype by means of a suppressor mutation. [L. revertans, pros.p. of reverto, to turn back]

review
review

drug utilization r. an authorized, structured, ongoing program that collects, analyzes, and interprets drug use patterns to improve the quality of drug use and patient outcomes.

Revilliod
Revilliod

Léon, Swiss physician, 1835–1919. See R. sign.

revivescence
revivescence (re-vi-ves′ens)

SYN: revivification (1) . [L. re-vivesco, to come to life again, fr. vivo, to live]

revivification
revivification (re-viv′i-fi-ka′shun)

1. Renewal of life and strength. SYN: revivescence. 2. Refreshening the edges of a wound by paring or scraping to promote healing. SYN: vivification. [L. re-, again, + vivo, to live, + facio, to make]

revulsion
revulsion (re-vul′shun)

SYN: derivation (1) . [L. revulsio, act of pulling away, fr. revello, pp. -vulsus, to pluck or pull away]

reward
reward (re-ward′)

SYN: reinforcer.

rewarming
rewarming (re-warm′ing)

Application of heat to correct hypothermia.

Rexed
Rexed

Bror A., Swedish physician, scientist, and public servant, *1914. See lamina of R..

Reye
Reye

Ralph Douglas Kenneth, 20th century Australian pathologist. See R. syndrome.

Reymond Reymond

See Du Bois-R..

Reynolds
Reynolds

Osborne, English physicist, 1842–1912. See R. number.

RF
RF

Abbreviation for releasing factors; rheumatoid factors, under factor; replicative form; reticular formation.

RFA
RFA

Abbreviation for right frontoanterior position.

RFLP
RFLP

Abbreviation for restriction fragment length polymorphism.

RFP
RFP

Abbreviation for right frontoposterior position.

RFT
RFT

Abbreviation for right frontotransverse position.

RH
RH

Abbreviation for releasing hormone.

Rh
Rh

1. Symbol for rhodium. 2. See R. blood group, Blood Groups appendix.

Rha
Rha

Abbreviation for l-rhamnose.

rhabarberone
rhabarberone (ra-bar′ber-on)

SYN: aloe-emodin.

rhabd- rhabd-

See rhabdo-.

rhabditiform
rhabditiform

See r. larva.

Rhabditis-like
Rhabditis-like

See rhabditiform larva.

rhabdo- rhabdo-, rhabd-

Rod; rod-shaped (rhabdoid). [G. rhabdos]

rhabdocyte
rhabdocyte (rab′do-sit)

Rarely used term for band cell or metamyelocyte. [rhabdo- + G. kytos, cell]

rhabdoid
rhabdoid (rab′doyd)

Rod-shaped. [rhabdo- + G. eidos, resemblance]

rhabdomyoblast
rhabdomyoblast (rab-do-mi′o-blast)

Large round, spindle-shaped, or strap-shaped cells with deeply eosinophilic fibrillar cytoplasm that may show cross striations; found in some rhabdomyosarcomas. [rhabdo- + G. mys, muscle, + blastos, germ]

rhabdomyolysis
rhabdomyolysis (rab′do-mi-ol′i-sis)

An acute, fulminating, potentially fatal disease of skeletal muscle that entails destruction of muscle, as evidenced by myoglobinemia and myoglobinuria. [rhabdo- + G. mys, muscle, + lysis, loosening]
acute recurrent r. [MIM*268200] repeated paroxysmal attacks of muscle pain and weakness followed by passage of dark red-brown urine, often precipitated by intercurrent illness and diagnosed by demonstration of myoglobin in the urine; it is attributed to abnormal phosphorylase activity in skeletal muscle, but there may be more than one biologic type; probably autosomal recessive inheritance. In some cases, at least, there is deficiency of carnitine palmitoyl transferase. SYN: familial paroxysmal r..
exertional r. r. produced in susceptible individuals by muscular exercise.
familial paroxysmal r. SYN: acute recurrent r..
idiopathic paroxysmal r. SYN: myoglobinuria.

rhabdomyoma
rhabdomyoma (rab′do-mi-o′ma)

A benign neoplasm derived from striated muscle, occurring in the heart in children, probably as a hamartomatous process. [rhabdo- + G. mys, muscle, + -oma, tumor]

rhabdomyosarcoma
rhabdomyosarcoma (rab′do-mi-o-sar-ko′ma)

A malignant neoplasm derived from skeletal (striated) muscle, occurring in children or, less commonly, in adults; classified as embryonal alveolar (composed of loose aggregates of small round cells) or pleomorphic (containing rhabdomyoblasts). SYN: rhabdosarcoma. [rhabdo- + G. mys, muscle, + sarkoma, sarcoma]
embryonal r. malignant neoplasm occurring in children, consisting of loose, spindle-celled tissue with rare cross-striations, and arising in many parts of the body in addition to skeletal muscles.

rhabdophobia
rhabdophobia (rab-do-fo′be-a)

Morbid fear of a rod (or switch) as an instrument of punishment. [rhabdo- + G. phobos, fear]

rhabdosarcoma
rhabdosarcoma (rab′do-sar-ko′ma)

SYN: rhabdomyosarcoma.

rhabdosphincter
rhabdosphincter (rab′do-sfingk′ter)

A sphincter made up of striated musculature. SYN: striated muscular sphincter. [rhabdo- + G. sphinkter, sphincter]

Rhabdoviridae
Rhabdoviridae (rab′do-vir′i-de)

A family of rod- or bullet-shaped viruses of vertebrates, insects, and plants, including rabiesvirus and vesicular stomatitis virus (of cattle). Virions (100–430 by 45–100 nm), formed by budding from surface membranes of cells, are enveloped and ether sensitive, with surface spikes 5–10 nm long; nucleocapsids contain negative sense single-stranded RNA (MW ∼4.4 × 10⁶) and are of helical symmetry. There are five genera: Vesiculovirus, Lyssavirus, Ephemerovirus, Nucleorhabdovirus, and Cytorhabdovirus.

rhabdovirus
rhabdovirus (rab′do-vi′rus)

Any virus of the family Rhabdoviridae.

rhachi- rhachi-

For words so beginning, see rachi-.

Rhadinovirus
Rhadinovirus (rad-en′o-vi-rus)

A herpesvirus genus, subfamily Gammaherpesvirinae, associated with Kaposi sarcoma.

rhagades
rhagades (rag′a-dez)

Chaps, cracks, or fissures occurring at mucocutaneous junctions; seen in vitamin deficiency diseases and in congenital syphilis. [G. rhagas, pl. r., a crack]

rhagadiform
rhagadiform (ra-gad′i-form)

Resembling or characterized by rhagades. [G. rhagas (rhagad-), crack, + L. forma, shape]

-rhagia -rhagia

See -rrhagia.

rhamnoside
rhamnoside (ram′no-sid)

A glycoside of rhamnose.

rhamnoxanthin
rhamnoxanthin (ram-no-zan′thin)

SYN: frangulin.

Rhamnus
Rhamnus (ram′nus)

A genus of shrubs and trees (family Rhamnaceae). The bark and berries of R. cathartica are cathartic; R. frangula is the source of frangula; R. purshiana is the source of cascara sagrada. SYN: buckthorn. [G. rhamnos]

rhaphania
rhaphania (ra-fa′ne-a)

SYN: raphania.

rhaphe
rhaphe (ra′fe)

SYN: raphe.

-rhaphy -rhaphy

See -rrhaphy.

rhe
rhe (re)

The absolute unit of fluidity, the reciprocal of the unit of viscosity. [G. rheos, a stream]

-rhea -rhea

See -rrhea.

rhegma
rhegma (reg′ma)

A rent or fissure. [G. breakage]

rhegmatogenous
rhegmatogenous (reg-ma-toj′e-nus)

Arising from a bursting or fractionating of an organ. See r. retinal detachment. [G. rhegma, breakage, + -gen, producing]

rheic
rheic (re′ik)

Relating to Rheum (rhubarb).

Rheinberg microscope
Rheinberg microscope

See under microscope.

rhenium
rhenium (Re) (re′ne-um)

A metallic element of the platinum group; atomic wt. 186.207, atomic no. 75. [Mod. L., fr. L. Rhenus, Rhine river]

rheo- rheo-

Blood flow; electrical current. [G. rheos, stream, current, flow]

rheobase
rheobase (re′o-bas)

The minimal strength of an electrical stimulus of indefinite duration that is able to cause excitation of a tissue, e.g., muscle or nerve. SEE ALSO: chronaxie. SYN: galvanic threshold. [rheo- + G. basis, a base]

rheobasic
rheobasic (re-o-ba′sik)

Pertaining to or having the characteristics of a rheobase.

rheocardiography
rheocardiography (re′o-kar-de-og′ra-phe)

Impedance plethysmography applied to the heart. [rheo- + cardiography]

rheochrysidin
rheochrysidin (re-o-kris′i-din)

The 3-methyl ether of emodin.

rheoencephalogram
rheoencephalogram (re′o-en-sef′a-lo-gram)

Graphic registration of the changes in conductivity of tissue of the head caused by vascular factors.

rheoencephalography
rheoencephalography (re′o-en-sef-a-log′ra-fe)

The technique of measuring blood flow of the brain; commonly used to denote impedance r., which uses changes in electrical impedance and resistance as a measure of flow. [rheo- + encephalography]

rheogram
rheogram (re′o-gram)

A plot of the shear stress versus the shear rate for a fluid. [rheo- + G. gramma, something written]

rheologist
rheologist (re-ol′o-jist)

A specialist in rheology.

rheology
rheology (re-ol′o-je)

The study of the deformation and flow of materials. [rheo- + G. logos, study]

rheometer
rheometer (re-om′e-ter)

1. An instrument for measurement of the rheologic properties of materials, e.g., of blood. 2. A galvanometer. [rheo- + G. metron, measure]

rheometry
rheometry (re-om′e-tre)

Measurement of electrical current or blood flow.

rheopexy
rheopexy (re′o-pek-se)

A property of certain materials in which an increased rate of shear favors an increase in viscosity. [rheo- + G. pexis, fixation]

rheostat
rheostat (re′o-stat)

A variable resistor used to adjust the current in an electrical circuit. [rheo- + G. statos, stationary]

rheostosis
rheostosis (re-os-to′sis)

A hypertrophying and condensing osteitis that tends to run in longitudinal streaks or columns, like wax drippings on a candle, and that involves a number of the long bones. SYN: flowing hyperostosis, streak hyperostosis. [rheo- + G. osteon, bone, + -osis, condition]

rheotaxis
rheotaxis (re-o-tak′sis)

A form of positive barotaxis, in which a microorganism in a fluid is impelled to move against the current flow of its medium. [rheo- + G. taxis, orderly arrangement]

rheotropism
rheotropism (re-ot′ro-pizm)

A movement contrary to the motion of a current, involving part of an organism, rather than the organism as a whole, as in rheotaxis. [rheo- + G. tropos, a turning]

rhestocythemia
rhestocythemia (res′to-si-the′me-a)

An obsolete term for the presence of broken-down red blood cells in the peripheral circulation. [G. rhaio, to destroy, + kytos, a hollow (a cell), + haima, blood]

rhesus
rhesus (re′sus)

Generic name for Macaca mulatta. [Mod. L., fr. L. R., G. Rhesos, a mythical king of Thrace]

rheum
rheum (room)

A mucous or watery discharge. [G. rheuma, a flux]

rheumatalgia
rheumatalgia (roo-ma-tal′je-a)

Obsolete term for rheumatic pain. [G. rheuma, flux, + algos, pain]

rheumatic
rheumatic (roo-mat′ik)

Relating to or characterized by rheumatism. SYN: rheumatismal. [G. rheumatikos, subject to flux, fr. rheuma, flux]

rheumatid
rheumatid (roo′ma-tid)

Rheumatic nodules or other eruptions that may accompany rheumatism. [G. rheum, flux, + -id (1)]

rheumatism
rheumatism (roo′ma-tizm)

1. Obsolete term for rheumatic fever. 2. Indefinite term applied to various conditions with pain or other symptoms of articular origin or related to other elements of the musculoskeletal system. [G. rheumatismos, rheuma, a flux]
articular r. SYN: arthritis.
cerebral r. central nervous system symptoms resulting from a rheumatic disease. Formerly seen primarily as a manifestation of rheumatic fever, now seen less frequently as a part of other diseases such as systemic lupus erythematosus. SEE ALSO: Sydenham chorea.
chronic r. a nonspecific disorder of the joints, slow in progress, producing a painful thickening and contraction of the fibrous structures, interfering with motion, and causing deformity.
gonorrheal r. an arthritis, usually initially a polyarthritis, but often localizing in one joint as a pyarthrosis caused by systemic infection with the gonococcus.
r. of the heart rheumatic cardiac valvular disease, most often of the mitral and aortic valves.
inflammatory r. rheumatoid arthritis or other cause of joint inflammation.
Macleod r. rheumatoid arthritis with abundant serous effusion in the affected joints.
muscular r. SYN: fibrositis (2) .
nodose r. 1. SYN: rheumatoid arthritis. 2. an acute or subacute articular r., accompanied by the formation of nodules on the tendons, ligaments, and periosteum in the neighborhood of the affected joints.
subacute r. a mild but usually protracted form of acute rheumatic fever, often resistant to treatment.
tuberculous r. an inflammatory condition of the joints or fibrous tissues during the course of tuberculosis.

rheumatismal
rheumatismal (roo-ma-tiz′mal)

SYN: rheumatic.

rheumatoid
rheumatoid (roo′ma-toyd)

Resembling r. arthritis in one or more features. [G. rheuma, flux, + eidos, resemblance]

rheumatologist
rheumatologist (roo-ma-tol′o-jist)

A specialist in rheumatology.

rheumatology
rheumatology (roo-ma-tol′o-je)

The medical specialty concerned with the study, diagnosis, and treatment of rheumatic conditions. [G. rheuma, flux, + logos, study]

rhigotic
rhigotic (ri-got′ik)

Pertaining to rhigosis.

rhIL-11
rhIL-11

SYN: recombinant human interleukin 11.

rhin- rhin-, rhino-

The nose. [G. rhis]

rhinal
rhinal (ri′nal)

SYN: nasal.

rhinalgia
rhinalgia (ri-nal′je-a)

Pain in the nose. SYN: rhinodynia. [rhin- + G. algos, pain]

rhinedema
rhinedema (ri′ne-de′ma)

Swelling of the nasal mucous membrane. [rhin- + G. oidema, swelling]

rhinencephalic
rhinencephalic (ri′nen-se-fal′ik)

Relating to the rhinencephalon.

rhinencephalon
rhinencephalon (ri′nen-sef′a-lon)

A largely archaic collective term denoting the parts of the cerebral hemisphere directly related to the sense of smell: the olfactory bulb, olfactory peduncle (together still listed as the first cranial nerve or olfactory nerve despite the fact that they form part of the central nervous system), olfactory tubercle, and olfactory or piriform cortex including the cortical nucleus of the amygdala. The term originally also encompassed the hippocampus, the entire amygdala, and the fornicate gyrus, all of which are no longer believed to be specifically related to the sense of smell. SEE ALSO: limbic system. SYN: smell-brain. [rhin- + G. enkephalos, brain]

rhinenchysis
rhinenchysis (ri-nen′ki-sis)

A nasal douche; washing out the nasal cavities. [rhin- + G. enchysis, a pouring in]

rhinion
rhinion (rin′e-on)

A craniometric point: the lower end of the internal suture. [G. r., nostril, dim. of rhis (rhin-), nose]

rhinism
rhinism (ri′nizm)

SYN: rhinolalia.

rhinitis
rhinitis (ri-ni′tis)

Inflammation of the nasal mucous membrane. SYN: nasal catarrh. [rhin- + G. -itis, inflammation]
acute r. an acute catarrhal inflammation of the mucous membrane of the nose, marked by sneezing, lacrimation, and a profuse secretion of watery mucus; usually associated with infection by one of the common cold viruses. SYN: coryza, head cold.
allergic r. r. associated with hay fever.
atrophic r. chronic r. with thinning of the mucous membrane; often associated with crusts and foul-smelling discharge. SYN: ozena.
r. caseosa, caseous r. a form of chronic r. in which the nasal cavities are more or less completely filled with an ill-smelling cheesy material.
chronic r. a protracted sluggish inflammation of the nasal mucous membrane; in the later stages the mucous membrane with its glands may be thickened (hypertrophic r.) or thinned (atrophic r.).
gangrenous r. cancrum nasi.
hypertrophic r. chronic r. with permanent thickening of the mucous membrane.
r. medicamentosa inflammation of the nasal mucous membrane secondary to excessive or improper topical medication.
scrofulous r. tuberculous infection of the nasal mucous membrane.
r. sicca a form of chronic r. with little or no secretion.
vasomotor r. congestion of nasal mucous membrane and rhinorrhea without infection or allergy.

rhino- rhino-

See rhin-.

rhinoanemometer
rhinoanemometer (ri′no-an-e-mom′e-ter)

SYN: rhinomanometer. [rhino- + G. anemos, wind, + metron, measure]

rhinocele
rhinocele (ri′no-sel)

Cavity (ventricle) of the rhinencephalon, the primitive olfactory part of the telencephalon. [rhino- + G. koilia, a hollow]

rhinocephaly
rhinocephaly, rhinocephalia (ri′no-sef′a-le, -se-fa′le-a)

Rhinencephaly;a form of cyclopia in which the nose is represented by a fleshy proboscis-like protuberance arising above the slitlike orbits, and the rhinencephalic lobes of the telencephalon are poorly developed with some tendency to become fused together. [rhino- + G. kephale, head]

Rhinocladiella
Rhinocladiella (ri′no-klad-e-el′a)

A genus of dematiaceous (dark colored) fungi, characterized by acrotheca, that cause chromoblastomycosis. SEE ALSO: Phialophora.

rhinocleisis
rhinocleisis (ri-no-kli′sis)

SYN: rhinostenosis. [rhino- + G. kleisis, a closure]

rhinodymia
rhinodymia (ri-no-dim′e-a)

Duplication of the nose on an otherwise normal face. [rhino- + G. -dymos, fold]

rhinodynia
rhinodynia (ri-no-din′e-a)

SYN: rhinalgia. [rhino- + G. odyne, pain]

rhinoestrosis
rhinoestrosis (ri′no-es-tro′sis)

Infection of horses and donkeys, rarely humans, with larvae of the fly Rhinoestrus purpureus; human infection is usually benign and of short duration, limited to the first stage of the larva and resulting in a mild ophthalmomyiasis.

Rhinoestrus purpureus
Rhinoestrus purpureus (ri-no-es′trus pur-poo′re-us)

A species of fly of the family Oestridae, the nasal botflies, that causes rhinoestrosis.

rhinogenous
rhinogenous (ri-noj′e-nus)

Originating in the nose. [rhino- + G. -gen, producing]

rhinokyphosis
rhinokyphosis (ri′no-ki-fo′sis)

A hump deformity of the nose. [rhino- + G. kyphosis, humped condition]

rhinolalia
rhinolalia (ri′no-la′le-a)

Nasalized speech. SYN: rhinism, rhinophonia. [rhino- + G. lalia, talking]
r. aperta abnormal speech attributable to inadequate velopharyngeal closure.
r. clausa abnormal speech attributable to nasal obstruction.

rhinolite
rhinolite (ri′no-lit)

SYN: rhinolith.

rhinolith
rhinolith (ri′no-lith)

A calcareous concretion in the nasal cavity often around a foreign body. SYN: nasal calculus, rhinolite. [rhino- + G. lithos, stone]

rhinolithiasis
rhinolithiasis (ri′no-li-thi′a-sis)

The presence of a nasal calculus. [rhinolith + G. -iasis, condition]

rhinologic
rhinologic (ri-no-loj′ik)

Relating to rhinology.

rhinologist
rhinologist (ri-nol′o-jist)

A specialist in diseases of the nose.

rhinology
rhinology (ri-nol′o-je)

The branch of medical science concerned with the nose and paranasal sinuses and their diseases. [rhino- + G. logos, study]

rhinomanometer
rhinomanometer (ri′no-ma-nom′e-ter)

A manometer used to determine the presence and amount of nasal obstruction, and the nasal air pressure and flow relationships. SYN: rhinoanemometer. [rhino- + manometer]

rhinomanometry
rhinomanometry (ri′no-ma-nom′e-tre)

1. The use of a rhinomanometer. 2. The study and measurement of nasal air flow and pressures.

rhinonecrosis
rhinonecrosis (ri′no-ne-kro′sis)

Necrosis of the bones of the nose. [rhino- + necrosis]

rhinopathy
rhinopathy (ri-nop′a-the)

Disease of the nose. [rhino- + G. pathos, suffering]

rhinopharyngeal
rhinopharyngeal (ri′no-fa-rin′je-al)

1. SYN: nasopharyngeal. 2. Relating to the rhinopharynx.

rhinopharyngolith
rhinopharyngolith (ri′no-fa-ring′go-lith)

A concretion in the nasopharynx. [rhinopharynx + G. lithos, stone]

rhinopharynx
rhinopharynx (ri′no-far′ingks)

SYN: nasopharynx. [rhino- + pharynx]

rhinophonia
rhinophonia (ri′no-fo′ne-a)

SYN: rhinolalia. [rhino- + G. phone, voice]

rhinophyma
rhinophyma (ri′no-fi′ma)

Hypertrophy of the nose with follicular dilation, resulting from hyperplasia of sebaceous glands with fibrosis and increased vascularity; a form of acne rosacea. SYN: brandy nose, copper nose, hammer nose, hypertrophic rosacea, potato nose, rum nose, rum-blossom, toper's nose. [rhino- + G. phyma, tumor, growth]

rhinoplasty
rhinoplasty (ri′no-plas-te)

1. Repair of a defect of the nose. 2. Plastic surgery to change the shape or size of the nose. [rhino- + G. plastos, formed]

rhinopneumonitis
rhinopneumonitis (ri′no-noo-mo-ni′tis)

Inflammation of the mucous membranes of the nose and lung. [rhino- + G. pneumon, lung, + -itis, inflammation]

rhinorrhea
rhinorrhea (ri-no-re′a)

A discharge from the nose. [rhino- + G. rhoia, flow]
cerebrospinal fluid r. a discharge of cerebrospinal fluid from the nose.
gustatory r. watery nasal discharge associated with eating.

rhinosalpingitis
rhinosalpingitis (ri′no-sal-pin-ji′tis)

Inflammation of the mucous membrane of the nose and eustachian tube. [rhino- + G. salpinx, tube, + -itis, inflammation]

rhinoscleroma
rhinoscleroma (ri′no-skle-ro′ma)

A chronic granulomatous process involving the nose, upper lip, mouth, and upper air passages; starts usually as a growth of hard smooth nodules in the anterior nares that spreads backward into the pharynx, larynx, trachea, and even into the bronchi; it may involve the external auditory meatus and is believed to be due to a specific bacterium, Klebsiella rhinoscleromatis. [rhino- + G. skleroma, an induration]

rhinoscope
rhinoscope (ri′no-skop)

A small mirror attached at a suitable angle to a rodlike handle, used in posterior rhinoscopy and nasopharyngoscopy.

rhinoscopic
rhinoscopic (ri′no-skop′ik)

Relating to the rhinoscope or to rhinoscopy.

rhinoscopy
rhinoscopy (ri-nos′ko-pe)

Inspection of the nasal cavity. [rhino- + G. skopeo, to view]
anterior r. inspection of the anterior portion of the nasal cavity with or without the aid of a nasal speculum.
median r. inspection of the roof of the nasal cavity and openings of the posterior ethmoid cells and sphenoidal sinus by means of a long-bladed nasal speculum or nasopharyngoscope.
posterior r. inspection of the nasopharynx and posterior portion of the nasal cavity by means of the rhinoscope, or with a nasopharyngoscope. SEE ALSO: nasopharyngoscopy.

rhinosinusitis
rhinosinusitis (ri-no-si-noo-si′tis)

Inflammation of the mucous membrane of the nose and paranasal sinuses.

rhinosporidiosis
rhinosporidiosis (ri′no-spo-rid-e-o′sis)

Invasion of the nasal cavity or, occasionally, the conjunctiva, or other superficial structures by Rhinosporidium seeberi, resulting in a chronic granulomatous disease producing polyps or other forms of hyperplasia on mucous membranes; it is found principally in India and Sri Lanka.

Rhinosporidium seeberi
Rhinosporidium seeberi (ri′nospo-rid′e-um se-be′ri)

A funguslike organism, of worldwide distribution and uncertain taxonomic position, found in certain vascular raspberry-like nasal polyps (rhinosporidiosis). [rhino- + G. sporidion, dim. of sporos, seed]

rhinostenosis
rhinostenosis (ri′no-ste-no′sis)

Nasal obstruction. SYN: rhinocleisis. [rhino- + G. stenosis, a narrowing]

rhinotomy
rhinotomy (ri-not′o-me)

1. Any cutting operation on the nose. 2. Operative procedure in which the nose is incised along one side so that it may be turned away to provide full vision of the nasal passages for radical sinus operations. [rhino- + G. tome, incision, cutting]

rhinotracheitis
rhinotracheitis (ri′no-tra-ke-i′tis)

Inflammation of the nasal cavities and trachea. [rhino- + trachea + -itis, inflammation]

Rhinovirus
Rhinovirus (ri′no-vi′rus)

A genus of acid-labile viruses (family Picornaviridae) of worldwide distribution, with a single-stranded positive sense RNA genome, associated with the common cold in humans. There are more than 110 antigenic types, formerly classified as M strains (culturable in rhesus monkey kidney and human cells) and H strains (growing only in cultures of human cells).

rhinovirus
rhinovirus

Any virus of the genus R..
bovine rhinoviruses viruses that cause widespread subclinical and occasionally mild clinical respiratory diseases of calves in the United States and Europe.
equine rhinoviruses viruses that cause inapparent as well as mild to relatively severe upper respiratory tract disease in the United States and Europe; most prevalent in breeding stables, and associated with high morbidity but negligible mortality; all equine isolates are related serologically to the original isolate.

Rhipicephalus
Rhipicephalus (ri-pi-sef′a-lus)

A genus of inornate hard ticks (family Ixodidae) consisting of about 50 species, all of which are Old World except R. sanguineus. Eyes and festoons are present in both sexes; short palpi and ventral plates are present only in the male. The genus includes important vectors of disease in humans and domestic animals. [G. rhipis, fan, + kephale, head]
R. sanguineus the brown dog tick, probably the most common and cosmopolitan species found on dogs in the U.S.; it may attack other animals but rarely attacks humans; it is a vector of Rocky Mountain spotted fever in Mexico and is a vector of the rickettsia of boutonneuse fever.

rhizo- rhizo-

Combining form denoting root. [G. rhiza]

rhizoid
rhizoid (ri′zoyd)

1. Rootlike. 2. Irregularly branching, like a root; denoting a form of bacterial growth. 3. In fungi, the rootlike hyphae that arise at the nodes of the hyphae of Rhizopus species. [rhizo- + G. eidos, resemblance]

rhizome
rhizome (ri′zom)

The creeping underground stem of plants such as iris, calamus, and sanguinaria. [G. rhizoma, mass of roots, fr. rhiza, root, + -oma, mass]

rhizomelia
rhizomelia (ri-zo-me′le-a)

1. Disproportion in the length of the most proximal segment of the limbs (upper arms and thighs). 2. A disorder involving the shoulder and hip joint. [rhizo- + G. melos, limb]

rhizomelic
rhizomelic (ri-zo-mel′ik)

Of or relating to the hip joint or the shoulder joint.

rhizomeningomyelitis
rhizomeningomyelitis (ri′zo-me-ning′go-mi-e-li′tis)

Inflammation of the nerve roots, the meninges, and the spinal cord. SYN: radiculomeningomyelitis. [rhizo- + G. meninx, membrane, + myelon, marrow, + -itis, inflammation]

Rhizomucor
Rhizomucor (ri-zo-moo-kor)

A genus of fungi in the family Mucoraceae; a cause of mucormycosis.

rhizoplast
rhizoplast (ri′zo-plast)

A fine connection between the flagellum or blepharoplast and the nucleus of a protozoan. [rhizo- + G. plastos, formed]

Rhizopoda
Rhizopoda (ri-zo-po′da)

A superclass in the subphylum Sarcodina that includes the amebae of humans, having pseudopodia of various forms but without axial filaments. SYN: Rhizopodasida, Rhizopodea. [rhizo + G. pous (pod-), foot]

Rhizopodasida
Rhizopodasida (ri′zo-po-das′i-da)

SYN: Rhizopoda.

Rhizopodea
Rhizopodea (ri-zo-po′de-a)

SYN: Rhizopoda. [rhizo- + G. pous (pod-), foot]

rhizopterin
rhizopterin (ri-zop′ter-in)

A folic acid factor for certain bacteria. SYN: SLR factor, Streptococcus lactis R factor.

Rhizopus
Rhizopus (ri-zo′pus)

A genus of fungi (class Zygomycetes, family Mucoraceae); some species cause mucormycosis in humans.

rhizotomy
rhizotomy (ri-zot′o-me)

Section of the spinal nerve roots for the relief of pain or spastic paralysis. SYN: radicotomy, radiculectomy. [G. rhiza, root, + tome, section]
anterior r. section of anterior spinal root.
facet r. a percutaneous radiofrequency lysis of the innervation of a facet.
posterior r. section of posterior spinal root. SYN: Dana operation.
trigeminal r. division or section of a sensory root of the fifth cranial nerve, accomplished through a subtemporal (Frazier-Spiller operation), suboccipital (Dandy operation), or transtentorial approach. SYN: retrogasserian neurectomy, retrogasserian neurotomy.

rho
rho (ρ) (ro)

1. The 17th letter of the Greek alphabet. 2. Symbol for density. 3. See r. factor.

rhod- rhod-

See rhodo-.

rhodamine B
rhodamine B (ro′da-men, -min) [C.I. 45170]

A fluorescent red basic xanthene dye, tetraethylrhodamine chloride, used in histology as a contrasting stain to methylene blue and methyl green, and as a vital fluorochrome.

rhodanate
rhodanate (ro′da-nat)

SYN: thiocyanate.

rhodanese
rhodanese (ro′da-nez)

SYN: thiosulfate sulfurtransferase.

rhodanic acid
rhodanic acid (ro-dan′ik)

SYN: thiocyanic acid.

rhodanile blue
rhodanile blue (ro′da-nil)

A dye mixture, considered by some to be a salt of rhodamine B and Nile blue, used to stain keratinized epithelium (red) and fibroblasts (blue), as well as spermatozoa and normal and pathologic acidophilic, basophilic, and certain neutrophilic elements of cells and tissues; used as a substitute for hematoxylin and eosin.

rhodeose
rhodeose (ro′de-os)

SYN: fucose.

rhodin
rhodin (ro′din)

A dihydroporphyrin derivative (the two additional hydrogens being at positions 17 and 18) of the type found in chlorophyll b and with a formyl group on position 7 rather than a methyl group.

rhodium
rhodium (Rh) (ro′de-um)

A metallic element, atomic no. 45, atomic wt. 102.90550. [Mod. L. fr. G. rhodon, a rose]

Rhodnius
Rhodnius (rod′ne-us)

Genus of reduvid bug that is the principal vector of Trypanosoma cruzi in Venezuela, Colombia, French Guiana, Guyana, and Surinam.
R. prolixus a reduvid bug, an important cause of South American trypanosomiasis.

rhodo- rhodo-, rhod-

Rosy, red color. [G. rhodon, rose]

Rhodococcus
Rhodococcus (ro-do-kok′us)

A genus of rod-shaped, Gram-positive, partially acid-fast, aerobic bacteria found in soil and in the feces of herbivores. Some species are pathogenic for animals and humans. The type species is R. rhodochrous.
R. equi a bacterial species causing bronchopneumonia and the formation of abscesses in the lungs of foals. It can cause bronchopneumonia in immunodeficient humans, especially those with AIDS. SYN: Corynebacterium equi.

rhodogenesis
rhodogenesis (ro′do-jen′e-sis)

The production of rhodopsin by the combination of 11-cis-retinal and opsin in the dark. [rhodopsin + G. genesis, production]

rhodophylactic
rhodophylactic (ro′do-fi-lak′tik)

Relating to rhodophylaxis.

rhodophylaxis
rhodophylaxis (ro′do-fi-lak′sis)

The action of the pigment cells of the choroid in preserving or facilitating the reproduction of rhodopsin. [rhodopsin + G. phylaxis, a guarding]

rhodopsin
rhodopsin (ro-dop′sin)

A purplish-red thermolabile protein, MW about 40,000, found in the external segments of the rods of the retina; it is bleached by the action of light, which converts it to opsin and all-trans-retinal, and is restored in the dark by rhodogenesis; the dominant protein in the plasma membrane of rod cells. SYN: visual purple.
r. kinase an enzyme that regulates r. function by phosphorylating activated r. at a number of sites; phosphorylated photoactivated r. binds to arrestin.

Rhodotorula
Rhodotorula (ro-do-tor′u-la)

A genus of yeasts, usually pink to red and of questionable pathogenicity, which are generally introduced iatrogenically in prosthetic implants and into immunocompromised patients via intravenous catheters.

rhombencephalon
rhombencephalon (rom-ben-sef′a-lon) [TA]

That part of the developing brain that is the most caudal of the three primary vesicles of the embryonic neural tube; secondarily divided into metencephalon and myelencephalon; the r. includes the pons, cerebellum, and medulla oblongata. SYN: hindbrain [TA] , hindbrain vesicle&star. [rhombo- + G. enkephalos, brain]

rhombic
rhombic (rom′bik)

1. SYN: rhomboid. 2. Relating to the rhombencephalon.

rhombo- rhombo-

Rhombic, rhomboid. [G. rhombos]

rhomboatloideus
rhomboatloideus

See musculus r..

rhombocele
rhombocele (rom′bo-sel)

SYN: rhomboidal sinus. [rhombo- + G. koilia, a hollow]

rhomboid
rhomboid, rhomboidal (rom′boyd, rom-boy′dal)

Resembling a rhomb; i.e., an oblique parallelogram, but having unequal sides; in anatomy, denoting especially a ligament and two muscles. SYN: rhombic (1) . [rhombo- + G. eidos, appearance]

rhomboideus
rhomboideus (rom-bo-id′e-us)

See rhomboid minor (muscle).

rhombomere
rhombomere

Segments of the developing neural tube in the rhombencephalon; nine rhombomeres appear in the developing human. [rhombencephalon + G. meros, part]

rhonchal
rhonchal, rhonchial (rong′kal, rong′ke-al)

Relating to or characteristic of a rhonchus.

rhonchus
rhonchus, pl .rhonchi (rong′kus, -ki)

An added sound with a musical pitch occurring during inspiration or expiration, heard on auscultation of the chest and caused by air passing through bronchi that are narrowed by inflammation, spasm of smooth muscle, or presence of mucus in the lumen; if low-pitched, it is called sonorous r.; if high-pitched, with a whistling or squeaky quality, sibilant r.. [L. fr. G. rhenchos, a snoring]
cavernous r. SYN: cavernous rale.

rhopheocytosis
rhopheocytosis (ro′fe-o-si-to′sis)

Formation of vacuoles at a cell surface without prior formation of cytoplasmic projections, by which the cell appears to aspirate surrounding material. SEE ALSO: pinocytosis. [G. rhopheo, to gulp down, or aspirate, + kytos, cell, + -osis, condition]

rhoptry
rhoptry, pl .rhoptries (rop′tre, -tres)

Electron-dense club-shaped, tubular or saccular organelles, extending back from the anterior end of sporozoites and other stages of certain sporozoans in the subphylum Apicomplexa. SYN: paired organelles, toxoneme. [G. rhopalon, club]

rhotacism
rhotacism (ro′ta-sizm)

Mispronunciation of the “r” sound. [G. rho, the letter r]

rhubarb
rhubarb (roo′barb)

Any plant of the genus Rheum (family Polygonaceae), especially R. rhaponticum, garden r., and R. officinale or R. palmatum; the last two species or their hybrids, deprived of periderm tissues, dried, and powdered, are used for their astringent, tonic and laxative effects.

Rhus
Rhus (roos, rus)

A genus of vines and shrubs (family Anacardiaceae) containing various species that are used for their ornamental foliage; formerly used in tanning. Certain poisonous species are classified as Toxicodendron. [L., fr. G. rhous, sumac]

rhypophobia
rhypophobia (ri-po-fo′be-a)

SYN: mysophobia. [G. rhypos, filth, + phobos, fear]

rhythm
rhythm (rith′um)

1. Measured time or motion; the regular alternation of two or more different or opposite states. 2. SYN: r. method. 3. Regular or irregular occurrence of an electrical event in the electrocardiogram or electroencephalogram. SEE ALSO: wave. 4. Sequential beating of the heart generated by a single beat or sequence of beats. [G. rhythmos]
agonal r. an idioventricular r., characterized by unusually wide and bizarre ventricular complexes, often seen in moribund patients.
alpha r. 1. a wave pattern in the encephalogram in the frequency band of 8–13 Hz; 2. the posterior dominant 8–13 Hz r. in the awake, relaxed person with closed eyes, that attenuates with eye opening. SYN: alpha wave, Berger r..
atrioventricular junctional r. the cardiac r. when the heart is controlled by the AV junction (including node); arising in the AV junction, the impulse ascends to the atria and descends to the ventricles, each at varying speeds depending on the site of the pacemaker; only descends to the ventricles in the common form of atrioventricular dissociation and in idiojunctional r.. SYN: AV junctional r., nodal bradycardia, nodal r..
AV junctional r. SYN: atrioventricular junctional r..
basic electrical r. (BER) a slow wave of depolarization of smooth muscle from the fundus to the pylorus that coordinates gastric peristalsis and emptying.
Berger r. SYN: alpha r..
beta r. a wave pattern in the electroencephalogram in the frequency band of 18–30 Hz. SYN: beta wave.
bigeminal r. that cardiac r. when each beat of the dominant r. (sinus or other) is followed by a premature beat, with the result that the heartbeats occur in pairs (bigeminy). SYN: coupled r..
cantering r. SYN: gallop.
chaotic r. completely irregular cardiac r. at varying rates. SEE ALSO: arrhythmia.
circadian r. circadian.
circus r. SYN: circus movement.
coronary nodal r. formerly applied by some authorities to the electrocardiographic pattern of normal upright P waves in leads I and II with a short P-R interval.
coronary sinus r. an ectopic atrial r. supposedly originating from a pacemaker at the mouth of the coronary sinus; recognized in the electrocardiogram by P-waves that are inverted in leads II, III, and aVF with a normal or prolonged P-R interval; an ectopic (“lower”) atrial r..
coupled r. SYN: bigeminal r..
delta r. a wave pattern in the electroencephalogram in the frequency band of 1.5–4.0 Hz.
diurnal r. diurnal.
ectopic r. any cardiac r. arising from a center other than the normal pacemaker, the sinus node.
escape r. three or more consecutive impulses at a rate not exceeding the upper limit of the inherent pacemaker; extreme range of impulse formation at the sinoatrial node is between 40 and 180 impulses per minute, that of the atrioventricular junction is normally 40–60 impulses per min, and the normal rate of the ventricular myocardium (idioventricular r.) is 20–40 impulses per min.
gallop r. SYN: gallop.
idiojunctional r. SYN: idionodal r..
idionodal r. an independent r., the ventricles being under control of the AV node (AV junction). SYN: idiojunctional r..
idioventricular r. a slow independent ventricular r. under control of a ventricular center (which is, by definition, ectopic). SYN: ventricular r..
junctional r. rhythms originating anywhere within the AV junction. Formerly, “AV nodal” or simply “nodal” rhythms.
nodal r. SYN: atrioventricular junctional r..
pendulum r. SYN: embryocardia.
quadrigeminal r. a cardiac arrhythmia in which the heartbeats are grouped in fours, each usually composed of one sinus beat followed by three extrasystoles, but a repetitive group of four of any composition is quadrigeminal. SYN: quadrigeminy.
quadruple r. a quadruple cadence to the heart sounds due to the easy audibility of both third and fourth heart sounds, indicative of serious myocardial disease. SYN: trainwheel r..
reciprocal r. a cardiac arrhythmia in which the impulse arising in the AV junction descends to and activates the ventricles on one intrajunctional pathway and simultaneously ascends toward the atria in parallel pathways; before reaching the atria, however, the impulse is reflected downward and again activates the ventricles, producing an echo or reciprocal beat; recognized in the electrocardiogram by the presence of an inverted P wave in lead aVF and usually II sandwiched between two ventricular complexes aberrantly, both of which may be normal or one of which may be conducted.
reciprocating r. a cardiac arrhythmia initiated by an AV junctional beat followed in turn by a reciprocal beat; the descending impulse of the reciprocal beat, before reaching the ventricles, is also reflected backward to the atria, but before reaching the atria is reflected downward again to the ventricles, so that there is both retrograde atrial activation and orthograde ventricular activation.
reversed reciprocal r. a cardiac arrhythmia in which a normal sinus impulse, before reaching the ventricles, is reflected backward to the atria; thus in the electrocardiogram a ventricular complex is sandwiched between a normal sinus P wave and a retrograde P wave; if the dysrhythmia continues, subsequent cycles are similar to those of reciprocating r..
sinus r. normal cardiac r. proceeding from the sinoatrial node; in healthy adults its rate is 60–90 beats/min.
systolic gallop r. obsolete term for extra sounds, usually clicks, heard during systole.
theta r. a wave pattern in the electroencephalogram in the frequency band of 4–7 Hz. SYN: theta wave.
tic-tac r. SYN: embryocardia.
trainwheel r. SYN: quadruple r..
trigeminal r. a cardiac arrhythmia in which the beats are grouped in trios, usually composed of a sinus beat followed by two extrasystoles. SYN: trigeminy.
triple r. a triple cadence to the heart sounds at any heart rate, due to the easy audibility of a third (S₃) (usually) or fourth (S₄) heart sound, or at faster rates a summation sound due to coincidence of the third and fourth heart sounds (“S₇” = S₃ + S₄).
ultradian r. ultradian.
ventricular r. SYN: idioventricular r..

rhytide
rhytide (ri′tid)

A skin wrinkle. [[G. rhytis, -idos, wrinkle]]

rhytidectomy
rhytidectomy (rit-i-dek′to-me)

Elimination of wrinkles from, or reshaping of, the face by excising any excess skin and tightening the remainder; the so-called face-lift. SYN: face-lift, rhytidoplasty. [G. rhytis (rhytid-), a wrinkle]

rhytidoplasty
rhytidoplasty (rit′i-do-plas-te)

SYN: rhytidectomy. [G. rhytis, a wrinkle, + plastos, formed]

rhytidosis
rhytidosis (rit-i-do′sis)

1. Wrinkling of the face to a degree disproportionate to age. 2. Laxity and wrinkling of the cornea, an indication of approaching death. SYN: rutidosis. [G. a wrinkling, fr. rhytis, a wrinkle, + -osis, condition]
r. retinae retinal wrinkling.

RIA
RIA

Abbreviation for radioimmunoassay.

Rib
Rib

Symbol for ribose. SYN: os costale.

rib- rib-

See ribo-.

ribavirin
ribavirin (ri′ba-vi-rin)

A synthetic nucleoside antiviral agent that, by its inhibitory effect on the synthesis of guanosine 5′-phosphate, inhibits both DNA and RNA synthesis; used for treatment of viral pneumonia caused by respiratory syncytial virus.

ribbon
ribbon (rib′on)

A r.-shaped structure. [M. E. riban]
Reil r. SYN: medial lemniscus.

Ribes
Ribes

François, French physician, 1765–1845. See R. ganglion.

ribitol
ribitol (ri′bi-tol)

Reduction product of ribose (–CHO at position 1 of ribose reduced to –CH₂OH). SYN: adonitol.

ribityl
ribityl (ri′bi-til)

The radical of ribitol; a constituent of riboflavin.

rib [I–XII]
rib [I–XII]

One of the 24 elongated curved bones forming the main portion of the bony wall of the chest. SYN: costa (1) . [A.S. ribb]
bicipital rib fusion of first thoracic rib with cervical vertebra.
bifid rib one in which the body bifurcates.
cervical rib [TA] a supernumerary rib articulating with a cervical vertebra, usually the seventh, but not reaching the sternum anteriorly. SEE ALSO: cervical rib syndrome. SYN: costa cervicalis [TA] .
false ribs five lower ribs on either side that do not articulate with the sternum directly. SYN: costae spuriae [VII–XII] [TA] , vertebrochondral ribs.
first rib [I] [TA] atypical rib having a single facet on its head, for articulation with the T1 vertebra, and the broadest, shortest and most sharply curved shaft; it also bears two transverse grooves on its superior surface for the subclavian vessels, separated by the scalene tubercle and ridge. SYN: costa prima [I] [TA] .
floating ribs [XI–XII] the two lower ribs on either side that are not attached anteriorly. SYN: costae fluctuantes [XI–XII], costae fluitantes, vertebral ribs.
lumbar rib [TA] an occasional rib articulating with the transverse process of the first lumbar vertebra.
rib notching a smooth defect in the lower border of one or more upper ribs caused by enlarged intercostal collateral vessels, most often a sign of coarctation of the aorta.
slipping rib subluxation of a rib cartilage, with costochondral separation.
true ribs [I–VII] seven upper ribs on either side whose cartilages articulate directly with the sternum. SYN: costae verae [I–VII] [TA] , vertebrosternal ribs.
vertebral ribs SYN: floating ribs [XI–XII].
vertebrochondral ribs SYN: false ribs.
vertebrosternal ribs SYN: true ribs [I–VII].

ribo- ribo-

1. Ribose. 2. As an italicized prefix to the systematic name of a monosaccharide, r. indicates that the configuration of a set of three consecutive, but not necessarily contiguous, CHOH (or asymmetric) groups is that of ribose; e.g., d-ribose, a trivial name, is d-r.pentose in systematic nomenclature. [German Ribose]

riboflavin
riboflavin, riboflavine (ri′bo-fla-vin)

A heat-stable factor of the vitamin B complex whose isoalloxazine nucleotides are coenzymes of the flavodehydrogenases. The daily human requirement is 1.7 mg for adult men and 1.3 mg for adult women, with a higher daily requirement during pregnancy and lactation; dietary sources include green vegetables, liver, kidneys, wheat germ, milk, eggs, cheese, and fish. SYN: flavin (1) , flavine, lactoflavin (2) , vitamin B₂ (1) .
r. kinase a cytosolic enzyme catalyzing the formation of flavin mononucleotide (r. phosphate) from r., utilizing ATP as phosphorylating agent. SYN: flavokinase.
methylol r. a mixture of methylol derivatives of r. formed by the action of formaldehyde on r. in weakly alkaline solution; it has the same action as r., but is preferred for parenteral administration.

riboflavin 5′-phosphate
riboflavin 5′-phosphate

SYN: flavin mononucleotide.

ribofuranose
ribofuranose (ri-bo-foor′a-nos)

The 1,4 cyclic furan form of ribose.

ribofuranosylthymine
ribofuranosylthymine (ri′bo-foor-an′o-sil-thi′men)

SYN: ribothymidine.

ribo-2-hexulose
ribo-2-hexulose

SYN: psicose.

ribonuclease
ribonuclease (RNase) (ri-bo-noo′kle-as)

A transferase or phosphodiesterase that catalyzes the hydrolysis of ribonucleic acid. SEE ALSO: r. (pancreatic), r. (Bacillus subtilis). SYN: ribonucleinase.
RNase A r. (pancreatic).
alkaline RNase r. (pancreatic).
RNase α an enzyme catalyzing endonucleolytic cleavage of O-methylated RNA yielding 5′-phosphomonoesters.
r. D (RNase D) an enzyme (endonuclease) that trims the extra 3′ nucleotides from immature tRNA.
Escherichia coli RNase I SYN: RNase T₂.
RNase I r. (pancreatic).
RNase II an enzyme cleaving RNA exonucleolytically in the 3′ to 5′ direction, yielding 5′-phosphomononucleotides. SEE ALSO: microbial RNase II.
RNase III an enzyme catalyzing endonucleolytic cleavage of double-stranded RNA, yielding 5′-phosphomonoesters.
microbial RNase II SYN: RNase T₂.
RNase N₁ SYN: RNase T₁.
RNase N₂ SYN: RNase T₂.
RNase P an enzyme catalyzing the endonucleolytic cleavage tRNA precursors to yield 5′-phosphomonoesters.
pancreatic RNase r. (pancreatic).
plant RNase SYN: RNase T₂.
RNase T₁ a nuclease endonucleolytically cleaving ribonucleic acids at the 3′-5′ link of a guanosine 3′-phosphate residue, producing oligonucleotides terminating in this nucleotide; a transferase (endonuclease) in the first (cyclizing) step, a phosphodiesterase on the second (hydrolyzing) step. SYN: guanyloribonuclease, RNase N₁.
RNase T₂ an enzyme endonucleolytically cleaving RNA to 3′-nucleotides with 2′,3′-cyclic nucleotides as intermediates. SYN: Escherichia coli RNase I, microbial RNase II, plant RNase, RNase N₂.
RNase U₂ an enzyme endonucleolytically cleaving RNA to 3′-phosphomono- and 3′-phosphooligonucleotides ending in adenylate or guanylate residues with 2′,3′-cyclic phosphate intermediates.
RNase U₄ SYN: yeast RNase.
yeast RNase an enzyme catalyzing the exonucleolytic cleavage of RNA to yield 3′-phosphomononucleotides. SYN: RNase U₄.

ribonuclease (Bacillus subtilis)
ribonuclease (Bacillus subtilis)

1. Ribonuclease (Azotobacter agilis); ribonuclease (Proteus mirabilis); an enzyme catalyzing the endonucleolytic cleavage of RNA to yield 2′,3′-cyclic nucleotides. 2. Ribonuclease T₁.

ribonuclease (pancreatic)
ribonuclease (pancreatic)

An enzyme isolated from the pancreas of ruminants that transfers the 3′-phosphate of a pyrimidine ribonucleotide residue in a polynucleotide from the 5′-position of the adjoining nucleotide to the 2′-position of the pyrimidine nucleotide itself (a transferase, endonuclease action), thus breaking the chain and forming a pyrimidine 2′,3′-cyclic phosphate, then (or independently) hydrolyzing this phosphodiester to leave a pyrimidine nucleoside 3′-phosphate residue (phosphodiesterase action); used in cytochemistry to selectively degrade and remove RNA as a control for staining of RNA.

ribonucleic acid
ribonucleic acid (RNA) (ri′bo-noo-kle′ik)

A macromolecule consisting of ribonucleoside residues connected by phosphate from the 3′-hydroxyl of one to the 5′-hydroxyl of the next nucleoside. RNA is found in all cells, in both nuclei and cytoplasm and in particulate and nonparticulate form, and also in many viruses; polynucleotides made in vitro are generally called such. Various RNA fractions are identified by location, form, or function.
acceptor RNA SYN: transfer RNA.
antisense RNA the transcription product of the DNA antisense strand; it can play a role in the inhibition of translation. SEE ALSO: antisense DNA.
chromosomal RNA RNA associated with the chromosome (not mRNA, tRNA, or rRNA) that may have a role in transcription.
heterogeneous nuclear RNA (hnRNA) an ill-defined form of RNA, of high molecular weight, that never leaves the nucleus and is thought to be the precursor of messenger RNA.
informational RNA SYN: messenger RNA.
initiation tRNA tRNA in prokaryotes containing a formyl-methionyl residue that initiates translation. SYN: formyl-methionyl-tRNA, starter tRNA.
messenger RNA (mRNA) the RNA reflecting the exact nucleoside sequence of the genetically active DNA and carrying the “message” of the latter, coded in its sequence, to the cytoplasmic areas where protein is made in amino acid sequences specified by the mRNA, and hence primarily by the DNA; viral RNAs are considered to be natural messenger RNAs. SYN: informational RNA, template RNA.
messengerlike RNA (mlRNA) heterogeneous nuclear RNA.
nuclear RNA (nRNA) rNA found in nuclei, or associated with DNA, or with nuclear structures (nucleoli).
RNA polymerase nucleotidyltransferases.
ribosomal RNA the RNA of ribosomes and polyribosomes.
small nuclear RNA (snRNA) small RNA ( i.e., about 90–300 nucleotides long) in the nucleus believed to have a role in RNA processing and cellular architecture.
soluble RNA (sRNA) SYN: transfer RNA. [soluble in molar salt]
starter tRNA SYN: initiation tRNA.
suppressor tRNA the tRNA associated with a suppressor mutation.
template RNA SYN: messenger RNA.
transfer RNA (tRNA) short-chain RNA molecules present in cells in at least 20 varieties, each variety capable of combining with a specific amino acid (see aminoacyl-tRNA). By joining (through their anticodons) with particular spots (codons) along the messenger RNA molecule and carrying their amino acyl residues along, they lead to the formation of protein molecules with a specific amino acid arrangement—the one ultimately dictated by a segment of DNA in the chromosomes. Each tRNA has about 80 nucleotides (MW about 25,000); most of the 20 varieties occur in multiple “isoacceptor” forms, separable by chromatography. Further subvarieties exist in, e.g., different strains of an organism, in subcellular organelles, and in different metabolic states. Cognate tRNAs are the tRNAs recognized by the specific amino acyl-tRNA synthetases. SYN: acceptor RNA, soluble RNA.

ribonucleinase
ribonucleinase (ri-bo-noo′kle-i-nas)

SYN: ribonuclease.

ribonucleoprotein
ribonucleoprotein (RNP) (ri′bo-noo′kle-o-pro′ten)

A combination of ribonucleic acid and protein.

ribonucleoside
ribonucleoside (ri-bo-noo′kle-o-sid)

A nucleoside in which the sugar component is ribose; the common ribonucleosides of RNA are adenosine, cytidine, guanosine, and uridine.

ribonucleotide
ribonucleotide (ri-bo-noo′kle-o-tid)

A nucleotide (nucleoside phosphate) in which the sugar component is ribose; the major ribonucleotides of RNA are adenylic acid, cytidylic acid, guanylic acid, and uridylic acid.
r. reductase a protein complex that converts r. diphosphates (NDPs) such as ADP and CDP to 2′-deoxyribonucleotide diphosphates (dNDPs) such as dADP and dCDP. This complex requires thioredoxin, thioredoxin reductase, and NADPH. It is crucial for DNA synthesis.

ribophorins
ribophorins (ri′-bo-for′inz)

Ribosome receptor proteins that interact specifically with the large ribosomal subunit and aid in translocation of newly synthesized proteins across the endoplasmic reticulum. [ribonucleic acid + G. phoros, carrying, + -in]

ribopyranose
ribopyranose (ri-bo-pir′a-nos)

The 1,5-cyclic form of ribose.

ribose
ribose (Rib) (ri′bos)

The pentose that, as the d-isomer, is present in ribonucleic acid; epimers of d-r. are d-arabinose, d-xylose, and l-lyxose.

ribose-5-phosphate
ribose-5-phosphate

Ribose phosphorylated on carbon-5; an intermediate in the pentose phosphate pathway.
ribose 5-phosphate isomerase an enzyme catalyzing interconversion of d-ribose 5-phosphate and d-ribulose 5-phosphate; of importance in ribose metabolism and in the pentose phosphate pathway. SYN: phosphopentose isomerase, phosphoriboisomerase.

riboside
riboside (ri′bo-sid)

The product formed by replacement of the H of the C-1 OH of ribose by an alcohol residue (which may be another sugar); differs from ribosyl compounds and does not occur in ribonucleic acids, where the radical is a ribosyl (1-OH missing entirely). See structure for methyl β-d-ribofuranoside below.

ribosome
ribosome (ri′bo-som)

A granule of ribonucleoprotein, 120–150 Å in diameter, that is the site of protein synthesis from aminoacyl-tRNAs as directed by mRNAs. SYN: Palade granule.

ribosuria
ribosuria (ri-bo-soo′re-a)

The enhanced urinary excretion of d-ribose; commonly one manifestation of muscular dystrophy. [ribose + G. ouron, urine]

ribosyl
ribosyl (ri′bo-sil)

The radical formed by loss of the hemiacetal OH group from either of the two cyclic forms of ribose (yielding ribofuranosyl and ribopyranosyl compounds), by combination with an H of an –NH– or a –CH– group; the natural nucleosides are r. compounds, not ribosides, as the bond between ribose and aglycon is C–N or C–C, not –C–O–X–.

ribosylation
ribosylation (ri-bo-sil-a-shun)

The covalent attachment of one or more ribosyl groups to a molecule (usually a macromolecule).
ADP r. covalent attachment of an ADP-ribosyl moiety to a macromolecule; E.G., the action of diphtheria toxin.

1-ribosylorotate
1-ribosylorotate (ri′bo-sil-or′o-tat)

SYN: orotidine.

ribosylpurine
ribosylpurine (ri′bo-sil-pur′en)

SYN: nebularine.

ribosylthymidine
ribosylthymidine

SYN: ribothymidine.

ribothymidine
ribothymidine (T, Thd) (ri-bo-thi′mi-den)

5-Methyluridine;the ribosyl analog of thymidine (deoxyribosylthymine); a nucleoside found in small amounts in ribonucleic acids. SYN: ribofuranosylthymine, ribosylthymidine.

ribothymidylic acid
ribothymidylic acid (rTMP, TMP) (ri′bo-thi-mi-dil′ik)

Ribothymidine 5′-phosphate;the ribose analog of thymidylic acid; a rare component of transfer RNAs.

ribotide
ribotide (ri′bo-tid)

A corruption of riboside, by analogy with nucleoside-nucleotide, to mean ribonucleotide.

ribovirus
ribovirus (ri′bo-vi′rus)

SYN: RNA virus.

ribozyme
ribozyme (ri′bo-zim)

A nonprotein biocatalyst; several cleave precursors of tRNA to yield functional tRNAs; others act on rRNA; plays a key role in intron splicing events. SYN: organic catalyst (1) , RNA enzyme. [ribonucleic acid + -zyme]

ribulose
ribulose (ri′bu-los)

The 2-keto isomer of ribose. As the 5-phosphate, it participates in the pentose monophosphate shunt; as the 1,5-bisphosphate, it combines with CO₂ at the start of the photosynthetic process in green plants (“carbon dioxide trap”); d-r. is the epimer of d-xylulose.

ribulose-1,5-bisphosphate carboxylase
ribulose-1,5-bisphosphate carboxylase

A dimerizing carboxy-lyase; an enzyme that catalyzes the addition of carbon dioxide to d-ribulose 1,5-bisphosphate and the hydrolysis of the addition product to two molecules of 3-d-phosphoglyceric acid, a key reaction in the fixation of CO₂ in photosynthesis. SYN: carboxydismutase.

ribulose-phosphate 3-epimerase
ribulose-phosphate 3-epimerase

An enzyme catalyzing the reversible interconversion of d-xylulose 5-phosphate and its epimer, d-ribulose 5-phosphate; a step in the nonoxidative phase of the pentose phosphate pathway. SYN: phosphoribulose epimerase.

Ricco
Ricco

Annibale, Italian astrophysicist, 1844–1919. See R. law.

rice
rice (ris)

The grain of Oryza sativa (family Gramineae), the r. plant; a food; also used, finely pulverized, as a dusting powder. [G. oryza]

Rich
Rich

Arnold R., U.S. pathologist, 1893–1968. See Hamman-R. syndrome.

Richards
Richards

Barry Wyndham, 20th century English physician. See R.-Rundle syndrome.

Richardson
Richardson

John Clifford, Canadian neurologist, *1909. See Steele-R.-Olszewski disease, Steele-R.-Olszewski syndrome.

Richter
Richter

August G., German surgeon, 1742–1812. See R. hernia, R.-Monro line, Monro-R. line.

Richter
Richter

Maurice N., U.S. pathologist, *1897. See R. syndrome.

ricin
ricin (ri′sin, ris′in)

A highly toxic lectin and hemagglutin occurring in the seeds (castor beans) of the castor oil plant, Ricinus communis; if eaten, acts as a violent irritant and may be fatal; an N-glycosidase that acts on the GOS subunit of rRNA.

ricinism
ricinism (ris′i-nizm)

Poisoning by ingestion of toxic principles from seeds (castor beans) or leaves of the castor oil plant, Ricinus communis.

ricinoleate
ricinoleate (ris-i-no′le-at)

A salt of ricinoleic acid.

ricinoleic acid
ricinoleic acid (ris-i-no-le′ik, ri-si-)

An unsaturated hydroxy acid present in castor oil.

Ricinus
Ricinus (ris′i-nus)

A genus of plants (family Euphorbiaceae) with one species, R. communis, the castor oil plant, the source of castor oil; the leaves are said to be a galactagogue. SYN: castor bean. [L.]

rickets
rickets (rik′ets)

A disease due to vitamin D deficiency and characterized by overproduction and deficient calcification of osteoid tissue, with associated skeletal deformities, disturbances in growth, hypocalcemia, and sometimes tetany; usually accompanied by irritability, listlessness, and generalized muscular weakness; fractures are frequent. SYN: infantile osteomalacia, juvenile osteomalacia, rachitis. [E. wrick, to twist]
acute r. SYN: hemorrhagic r..
adult r. SYN: osteomalacia.
celiac r. arrested growth and osseous deformities associated with defective absorption of fat and calcium in celiac disease.
familial hypophosphatemic r. SYN: vitamin D-resistant r..
hemorrhagic r. bone changes seen in infantile scurvy, consisting of subperiosteal hemorrhage and deficient osteoid tissue formation; often used to indicate simultaneous occurrence of r. and scurvy. SYN: acute r..
hereditary hypophosphatemic r. with hypercalciuria, an inherited disorder in which there is a defect in renal tubular reabsorption.
late r. SYN: osteomalacia.
refractory r. r. that does not respond to treatment with usual doses of vitamin D and adequate dietary calcium and phosphorus; most often due to inherited renal tubular disorder, e.g., Fanconi syndrome.
renal r. a form of r. occurring in children in association with and apparently caused by renal disease with hyperphosphatemia. SYN: pseudorickets, renal fibrocystic osteosis, renal infantilism, renal osteitis fibrosa.
scurvy r. SYN: infantile scurvy.
vitamin D-resistant r. a group of metabolic disorders characterized by renal tubular defect in phosphate transport and bone abnormalities resulting in hypophosphatemic r. or osteomalacia; hypocalcemia and tetany are not features. There is an autosomal dominant form [MIM*193100] and an X-linked dominant form [MIM*307800], the latter caused by mutation in the phosphate-regulating gene with homologies to endopeptidases (PHEX) on chromosome Xp. Both forms are not responsive to standard therapeutic doses of vitamin D but they may respond to very large doses of phosphate and/or vitamin D. There is also an autosomal recessive form [MIM*277440] caused by mutation in the vitamin D receptor gene (VDR) on 12q. SYN: familial hypophosphatemic r..

Ricketts
Ricketts

Howard T., U.S. pathologist, 1871–1910. See Rickettsia.

Rickettsia
Rickettsia (ri-ket′se-a)

A genus of bacteria (order Rickettsiales) containing small (nonfilterable), often pleomorphic, coccoid to rod-shaped, Gram-negative organisms that usually occur intracytoplasmically in lice, fleas, ticks, and mites but do not grow in cell-free media; pathogenic species infect humans and other animals, causing epidemic typhus, murine, or endemic typhus, Rocky Mountain spotted fever, tsutsugamushi disease, rickettsialpox, and other diseases; type species is R. prowazekii. [Howard T. Ricketts]
R. africae a species of R. studied principally in Zimbabwe that appears to be carried by the tick Amblyomma hebraeum; a cause of spotted fever.
R. akari a bacterial species causing human rickettsialpox; transmitted by the house mouse mite, Liponyssoides sanguineus; a mild febrile disease of 7–10 days is produced with an urban distribution in the northeastern U.S. and in wild or commensal rodents in the countries of the former USSR and Africa.
R. australis a bacterial species causing a spotted fever, North Queensland tick typhus, clinically and serologically similar to the disease caused by the agent of rickettsialpox; Ixodes holocyclus and I. tasmani are probable vectors. Small marsupials are suspected reservoirs of this agent, which is found over much of coastal Queensland, especially in secondary scrub and savannah.
R. burnetii former name for Coxiella burnetii.
R. canis former name for Ehrlichia canis.
R. conorii a species of bacteria causing boutonneuse fever in southern Europe, Africa, and the Middle East; transmitted by various ticks, such as the dog tick Rhipicephalis sanguineus.
R. honei a bacterial species causing Flinders Island spotted fever in Australia.
R. japonica a bacterial species causing Japanese spotted fever.
R. mooseri a species similar to R. prowazekii but with less variation in appearance; the resultant endemic typhus is milder and has a somewhat slower onset.
R. prowazekii a bacterial species causing epidemic and recrudescent typhus, transmitted by body lice; type species of the genus R..
R. psittaci former name for Chlamydia psittaci.
R. rickettsii a bacterial species, the agent of Rocky Mountain spotted fever, South African tick-bite fever, São Paulo exanthematic typhus of Brazil, Tobia fever of Colombia, and spotted fevers of Minas Gerais and Mexico; transmitted by infected ixodid ticks, especially Dermacentor andersoni and D. variabilis.
R. sennetsu SYN: Ehrlichia sennetsu.
R. sibirica a bacterial species, the agent of Siberian or North Asian tick typhus, transmitted by various ixodid ticks, which also serve as reservoirs, possibly aided by rodents and hares; the disease resembles Rocky Mountain spotted fever.
R. slovaca a bacterial species causing a newly recognized rickettsiosis associated with local erythema and possibly meningoencephalitis; transmitted by the tick Dermacentor marginatus.
R. tsutsugamushi former name for Orientia tsutsugamushi.
R. typhi a bacterial species causing murine or endemic typhus fever, transmitted by the rat flea.

rickettsial
rickettsial (ri-ket′se-al)

Pertaining to or caused by rickettsiae.

rickettsialpox
rickettsialpox (ri-ket′se-al-poks′)

Infection with Rickettsia akari, which is spread by mites from reservoir in house mice; a benign, self-limited process first recognized in 1946 in the Kew Gardens area of New York City; a few limited outbreaks have been observed elsewhere since then. SYN: Kew Gardens fever, mite-born typhus, vesicular rickettsiosis.

rickettsiosis
rickettsiosis (ri-ket-se-o′sis)

Infection with rickettsiae.
vesicular r. SYN: rickettsialpox.

rickettsiostatic
rickettsiostatic (ri-ket′se-o-stat′ik)

An agent inhibitory to the growth of Rickettsia. [Rickettsia + G. statikos, bringing to a standstill]

rickety
rickety (rik′e-te)

SYN: rachitic.

Rickles
Rickles

Norman H., U.S. oral pathologist, *1920. See R. test.

RID
RID

Abbreviation for radial immunodiffusion.

Riddoch
Riddoch

George, British physician, 1888–1947. See R. phenomenon. SEE ALSO: R. phenomenon.

Rideal
Rideal

Samuel, English chemist and bacteriologist, 1863–1929. See R.-Walker coefficient, R.-Walker method.

ridge
ridge (rij)

1. A (usually rough) linear elevation. SEE ALSO: crest. 2. In dentistry, any linear elevation on the surface of a tooth. 3. The remainder of the alveolar process and its soft tissue covering after the teeth are removed. [A. S. hyrcg, back, spine]
alveolar r. SYN: alveolar process of maxilla.
apical ectodermal r. the layer of surface ectodermal cells at the apex of the embryonic limb bud; thought to exert an inductive influence on the condensation of underlying mesenchyme and be necessary for continued outgrowth of the limb.
basal r. 1. SYN: alveolar process of maxilla. 2. SYN: cingulum of tooth.
bicipital ridges SYN: crest of greater tubercle, crest of lesser tubercle.
buccocervical r. a convexity within the cervical third of the buccal surface of molars.
buccogingival r. a distinct r. on the buccal surface of a deciduous molar tooth, approximately 1.5 mm from the crown-root junction.
bulbar r. one of two spiral subendocardial thickenings in the embryonic bulbus cordis; when they fuse, they divide the bulbus into the aorta and pulmonary artery.
bulboventricular r. an elevation on the inner surface of the embryonic heart at 4–5 weeks; it indicates the division between the developing ventricles and the bulbus cordis.
dental r. the prominent border of a cusp or margin of a tooth.
dermal ridges [TA] surface ridges of the epidermis of the palms and soles, where the sweat pores open. SYN: cristae cutis [TA] , epidermal ridges, papillary ridges, skin ridges.
epidermal ridges SYN: dermal ridges.
epipericardial r. an elevation separating the developing pharyngeal region from the embryonic pericardium.
external oblique r. SYN: oblique line of mandible.
ganglion r. SYN: neural crest.
genital r. SYN: gonadal r..
gluteal r. SYN: gluteal tuberosity.
gonadal r. an elevation of thickened mesothelium and underlying mesenchyme on the ventromedial border of the embryonic mesonephros; the primordial germ cells become embedded in it, establishing it as the primordium of the testis or ovary. SYN: genital r..
interpapillary ridges SYN: rete r..
key r. SYN: zygomaxillare.
lateral epicondylar r. SYN: lateral supraepicondylar r..
lateral supracondylar r. lateral supraepicondylar r..
lateral supraepicondylar r. [TA] the distal sharp portion of the lateral margin of the humerus. SYN: crista supraepicondylaris lateralis [TA] , crista supracondylaris lateralis&star, lateral supracondylar r.&star, lateral epicondylar crest, lateral epicondylar r., lateral supracondylar crest.
linguocervical r. SYN: linguogingival r..
linguogingival r. a r. occurring on the lingual surface, near the cervix, of the incisor and cuspid teeth. SYN: linguocervical r..
Mall ridges rarely used eponym for pulmonary ridges.
mammary r. bandlike thickening of ectoderm in the embryo extending on either side from just below the axilla to the inguinal region; in human embryos, the mammary glands arise from primordia in the thoracic part of the r., the balance of the r. disappearing; in some lower mammals that give birth to a litter of young, several milk glands develop along these lines. SYN: mammary fold, milk line, milk r..
marginal r. SYN: marginal crest of tooth.
medial epicondylar r. SYN: medial supraepicondylar r..
medial supracondylar r. medial supraepicondylar r..
medial supraepicondylar r. [TA] the distal sharp portion of the medial margin of the humerus. SYN: crista supraepicondylaris medialis [TA] , crista supracondylaris medialis&star, medial supracondylar r.&star, medial epicondylar crest, medial epicondylar r., medial supracondylar crest.
mesonephric r. a r. that, in early human embryos, composes the entire urogenital r.; however, later in development a more medial genital r., the potential gonad, is demarcated from it. SEE ALSO: urogenital r.. SYN: mesonephric fold.
milk r. SYN: mammary r..
mylohyoid r. SYN: mylohyoid line.
nasal r. SYN: agger nasi.
oblique r. a r. on the masticatory surface of an upper molar tooth from the mesiolingual to the distobuccal cusp.
oblique r. of trapezium SYN: tuberculum of trapezium bone.
palatine r. SYN: palatine raphe.
papillary ridges SYN: dermal ridges.
Passavant r. a prominence on the posterior wall of the nasopharynx formed by contraction of the superior constrictor muscle of the pharynx during swallowing. SYN: Passavant bar, Passavant cushion, Passavant pad.
pectoral r. SYN: crest of greater tubercle.
pharyngeal r. SYN: posterior fascicle of palatopharyngeus muscle.
primitive r. one of the paired ridges on either side of the primitive groove.
pronator r. an oblique r. on the anterior surface of the ulna, giving attachment to the pronator quadratus muscle.
pterygoid r. of sphenoid bone SYN: infratemporal crest of greater wing of sphenoid.
pulmonary ridges a pair of ridges overlying the common cardinal veins and bulging from the lateral body wall into the embryonic celom; so called because they give early indication of where the pleuropericardial folds will develop.
residual r. that portion of the processus alveolaris remaining in the edentulous mouth following resorption of the section containing the alveoli.
rete r. downward thickening of the epidermis between the dermal papillae; peg is a misnomer because the dermal papillae are cylindric but the epidermal thickening between papillae is not. SYN: interpapillary ridges, rete pegs.
skin ridges SYN: dermal ridges.
sphenoidal ridges sharp posterior margins of the lesser wings of the sphenoid bone that end medially in the anterior clinoid process; the sphenoidal ridges demarcate the anterior cranial fossa from the lateral part of the middle cranial fossa.
superciliary r. SYN: superciliary arch.
supplemental r. a r. on the surface of a tooth that is not normally present.
supraorbital r. SYN: supraorbital margin.
taste r. one of the ridges surrounding the vallate papillae of the tongue.
temporal r. SYN: inferior temporal line of parietal bone, superior temporal line of parietal bone.
transverse r. [TA] SYN: crista transversalis.
transverse palatine r. SYN: transverse palatine fold.
transverse ridges of sacrum [TA] one of four ridges that cross the pelvic surface of the sacrum; these mark the positions of the intervertebral disks between the bodies of the five sacral vertebrae in the immature bone. SYN: lineae transversae ossis sacri [TA] .
trapezoid r. SYN: trapezoid line.
triangular r. [TA] SYN: crista triangularis.
urogenital r. one of the paired longitudinal ridges developing in the dorsal body wall of the embryo on either side of the dorsal mesentery; the r. is formed at first by the growing mesonephros and later by the mesonephros and the gonad. SYN: genital fold, wolffian r..
wolffian r. SYN: urogenital r..

Ridley
Ridley

Humphrey, English anatomist, 1653–1708. See R. circle, R. sinus, circulus venosus ridleyi.

Riedel
Riedel

Bernhard M.C.L., German surgeon, 1846–1916. See R. disease, R. lobe, R. struma, R. thyroiditis.

Rieder
Rieder

Hermann, German pathologist, 1858–1932. See R. cells, under cell, R. cell leukemia, R. lymphocyte.

Riegel
Riegel

Franz, German physician, 1843–1904. See R. pulse.

Rieger
Rieger

Herwigh, German ophthalmologist. See R. anomaly, R. syndrome.

Riehl
Riehl

Gustav, Austrian dermatologist, 1855–1943. See R. melanosis.

RIF
RIF

Abbreviation for resistance-inducing factor.

rifampicin
rifampicin (rif′am-pi-sin)

SYN: rifampin.

rifampin
rifampin (rif′am-pin)

A first-line antituberculosis drug; a bactericidal agent used in the treatment of tuberculosis and other infections, that, like all antituberculosis drugs, must not be used alone in the treatment of active tuberculosis; a powerful inducer of hepatic microsomal enzymes. SYN: rifampicin.

rifamycin
rifamycin, rifomycin (rif-a-mi′sin, rif-o-)

A complex antibiotic, isolated from Nocardia mediterranei, that is active against Mycobacterium tuberculosis and Staphylococcus aureus; it is poorly absorbed from the gastrointestinal tract and often causes irritation and severe pain at the sites of injection.

Riga
Riga

Antonio, Italian physician, 1832–1919. See R.-Fede disease.

right-eyed
right-eyed (rit-id)

SYN: dextrocular.

right-footed
right-footed (rit′fut-ed)

SYN: dextropedal.

right-handed
right-handed (rit′hand-ed)

Denoting the habitual or more skillful use of the right hand for writing and most manual operations. SYN: dextral, dextromanual.

rigidity
rigidity (ri-jid′i-te)

1. Stiffness or inflexibility. SYN: rigor (1) . 2. In psychiatry and clinical psychology, an aspect of personality characterized by an individual's resistance to change. 3. In neurology, one type of increase in muscle tone at rest; characterized by increased resistance to passive stretch, independent of velocity and symmetric about joints; increases with activation of corresponding muscles in the contralateral limb. Two basic types are cogwheel r. and lead-pipe r.. SEE ALSO: nuchal r.. [L. rigidus, rigid, inflexible]
cadaveric r. SYN: rigor mortis.
catatonic r. r. associated with catatonic psychotic states in which all muscles exhibit flexibilitas cerea.
cerebellar r. increased tone of the extensor muscles, related to injury of the vermis of the cerebellum.
clasp-knife r. SYN: clasp-knife spasticity.
cogwheel r. a type of r. seen in parkinsonism in which the muscles respond with cogwheel-like jerks to the use of constant force in bending the limb.
decerebrate r. a postural change that occurs in some comatose patients, consisting of episodes of opisthotonos, rigid extension of the limbs, internal rotation of the upper extremities, and marked plantar flexion of the feet; produced by a variety of metabolic and structural brain disorders. SYN: decerebrate state.
decorticate r. a unilateral or bilateral postural change, consisting of the upper extremities flexed and adducted and the lower extremities in rigid extension; due to structural lesions of the thalamus, internal capsule, or cerebral white matter. SYN: decorticate state.
lead-pipe r. the plastic type of r. resembling that of a pipe of lead seen in certain forms of parkinsonism.
nuchal r. impaired neck flexion resulting from muscle spasm (not actual r.) of the extensor muscles of the neck; usually attributed to meningeal irritation.
ocular r. the resistance offered by the eyeball to a change in intraocular volume; manifested as a change in intraocular pressure.
postmortem r. SYN: rigor mortis.
scleral r. the resistance of the eye to changes in shape with changes in intraocular pressure.

rigor
rigor (rig′er)

1. SYN: rigidity (1) . 2. SYN: chill (2) . [L. stiffness]
acid r. coagulation of muscle protein induced by acids.
calcium r. arrest of the heart in the fully contracted state as a result of poisoning with calcium.
heat r. coagulation of muscle protein induced by heat.
r. mortis stiffening of the body, 1–7 hours after death, from hardening of the muscular tissues as a consequence of the coagulation of the myosinogen and paramyosinogen; it disappears after 1–6 days or when decomposition begins. SYN: cadaveric rigidity, postmortem rigidity.
myocardial r. mortis SYN: ischemic contracture of the left ventricle.

Riley
Riley

Conrad M., U.S. pediatrician, *1913. See R.-Day syndrome.

Riley
Riley

Harris D., Jr., 20th century U.S. physician. See Smith-R. syndrome.

riluzole
riluzole (ril′oo-zol)

A drug used to treat amyotrophic lateral sclerosis; mechanism of action not known.

rim
rim

A margin, border, or edge, usually circular in form.
bite r. SYN: occlusion r..
occlusal r. SYN: occlusion r..
occlusion r. occluding surfaces built on temporary or permanent denture bases for the purpose of making maxillomandibular relation records and for arranging teeth. SYN: bite r., occlusal r., record r..
orbital r. SYN: orbital margin.
record r. SYN: occlusion r..

rima
rima, gen. and pl. rimae (ri′ma, ri′me) [TA]

A slit or fissure, or narrow elongated opening between two symmetric parts. [L. a slit]
r. glottidis [TA] the interval between the true vocal cords. SYN: r. vocalis&star, glottis vera, true glottis.
r. oris [TA] SYN: oral fissure.
r. palpebrarum [TA] SYN: palpebral fissure.
r. pudendi [TA] SYN: pudendal cleft.
r. respiratoria SYN: r. vestibuli.
r. vestibuli [TA] the interval between the false vocal cords or vestibular folds. SYN: false glottis, glottis spuria, r. respiratoria.
r. vocalis r. glottidis.
r. vulvae SYN: pudendal cleft.

rimantadine
rimantadine (ri-man′ta-den)

An antiviral agent resembling amantadine in its activity but seemingly with fewer central nervous system adverse reactions.

Rimini test
Rimini test

See under test.

rimose
rimose (ri′mos)

Fissured; marked by cracks in all directions, like the crackle of porcelain. [L. rimosus, fr. rima, a fissure]

rimula
rimula (rim′u-la)

A minute slit or fissure. [L. dim. of rima]

Rindfleisch
Rindfleisch

Georg E., German physician, 1836–1908. See R. folds, under fold.

ring
ring (ring) [TA]

1. A circular band surrounding a wide central opening; a r.-shaped or circular structure surrounding an opening or level area. SYN: anulus [TA] . 2. The closed ( i.e., endless) chain of atoms in a cyclic compound; commonly used for “cyclic” or “cycle.” 3. A marginal growth on the upper surface of a broth culture of bacteria, adhering to the sides of the test tube in the form of a circle. SYN: annulus. [A.S. hring]
abdominal r. SYN: deep inguinal r..
amnion r. the r. formed by the attachment of the amnion to the umbilical cord at its point of emergence from the umbilicus.
annuloplasty r. the dilated annulus is sutured, often to a prosthetic r., thereby reducing it to its normal systolic size.
anterior limiting r. SYN: anterior limiting lamina.
Balbani r. an extremely large puff at a band of a polytene chromosome.
benzene r. the closed-chain arrangement of the carbon and hydrogen atoms in the benzene molecule. SEE ALSO: cyclic compound.
Bickel r. SYN: pharyngeal lymphatic r..
Cannon r. SYN: Cannon point.
cardiac lymphatic r. SYN: lymph nodes around cardia of stomach, under lymph node.
casting r. SYN: refractory flask.
choroidal r. a lightly pigmented crescent or r. adjacent to the optic disk.
ciliary r. SYN: orbiculus ciliaris.
common tendinous r. of extraocular muscles [TA] a fibrous r. that surrounds the optic canal and the medial part of the superior orbital fissure; it gives origin to the four rectus muscles of the eye and is partially fused with the sheath of the optic nerve. SYN: anulus of Zinn, anulus tendineus communis, Zinn ligament, Zinn r., Zinn tendon.
conjunctival r. [TA] a narrow r. at the junction of the periphery of the cornea with the conjunctiva. SYN: anulus conjunctivae [TA] .
constriction r. 1. true spastic stricture of the uterine cavity resulting when a zone of muscle goes into local tetanic contraction and forms a tight constriction about some part of the fetus; 2. SYN: amnionic band.
crural r. SYN: femoral r..
deep inguinal r. [TA] the opening in the transversalis fascia through which the ductus deferens and gonadal vessels (or round ligament in the female) enter the inguinal canal. Located midway between anterior superior iliac spine and pubic tubercle, it is bounded medially by the lateral umbilical fold (inferior epigastric vessels) and inferiorly by the iliopubic tract. Indirect inguinal hernias exit the abdominal cavity via the deep inguinal r. SYN: anulus inguinalis profundus [TA] , abdominal r., anulus abdominalis, internal inguinal r..
external inguinal r. SYN: superficial inguinal r..
femoral r. [TA] the superior opening of the femoral canal, bounded anteriorly by the inguinal ligament, posteriorly by the pectineus muscle, medially by the lacunar ligament, and laterally by the femoral vein. Passageway by which many lymphatics from lower limb pass to abdomen. Accommodates enlargement of femoral vein in Valsalva maneuver. Often occupied by a lymph node (Cloquet) and is the site of femoral hernias. SYN: anulus femoralis [TA] , crural r..
fibrocartilaginous r. of tympanic membrane [TA] the thickened portion of the circumference of the tympanic membrane that is fixed in the tympanic sulcus. SYN: anulus fibrocartilagineus membranae tympani [TA] , Gerlach annular tendon.
fibrous r. 1. SYN: (right and left) fibrous rings of heart. 2. SYN: anulus fibrosus of intervertebral disk.
fibrous r. of intervertebral disk SYN: anulus fibrosus of intervertebral disk.
Fleischer r. an incomplete r. often present at the base of the keratoconus cone; it may be yellow or greenish from deposition of hemosiderin.
Fleischer-Strümpell r. SYN: Kayser-Fleischer r..
Flieringa r. a stainless steel r. sutured to the sclera to prevent collapse of the globe in difficult intraocular operations.
gestational r. the white r. identified by pulse echosonography that signals an early stage of pregnancy.
glaucomatous r. SYN: glaucomatous halo (1) .
Graefenberg r. obsolete term for a silver or silkworm gut r. designed for insertion into the uterine cavity as a means of contraception.
greater r. of iris SYN: outer border of iris.
internal inguinal r. SYN: deep inguinal r..
r. of iris SYN: border of iris.
Kayser-Fleischer r. a greenish yellow pigmented r. encircling the cornea just within the corneoscleral margin, seen in hepatolenticular degeneration, due to copper deposited in Descemet membrane. SYN: Fleischer-Strümpell r..
lesser r. of iris SYN: inner border of iris.
Liesegang rings colored rings of precipitated silver chromate formed when a drop of concentrated silver nitrate is added to the surface of a gel (such as gelatin, agar, or silica gel) containing potassium dichromate.
Lower r. SYN: (right and left) fibrous rings of heart.
lymphatic r. of cardiac part of stomach SYN: lymph nodes around cardia of stomach, under lymph node.
neonatal r. SYN: neonatal line.
pathologic retraction r. a constriction located at the junction of the thinned lower uterine segment with the thick retracted upper uterine segment, resulting from obstructed labor; this is one of the classic signs of threatened rupture of the uterus.
pharyngeal lymphatic r. [TA] the broken r. of lymphoid tissue, formed of the lingual, faucial, and pharyngeal tonsils. SYN: anulus lymphoideus pharyngis [TA] , Bickel r., tonsillar r., Waldeyer throat r..
physiologic retraction r. a ridge on the inner uterine surface at the boundary line between the upper and lower uterine segment that occurs in the course of normal labor.
polar r. a thickened, electron-dense r. at the anterior end of certain stages of the Apicomplexa; part of the apical complex characteristic of these sporozoans.
(right and left) fibrous rings of heart [TA] two fibrous rings that surround atrioventricular orifices of the heart, providing attachment for the atrioventricular valve leaflets and maintaining patency of the orifices. As part of the fibrous skeleton of the heart, the fibrous rings also provide origin and insertion for the myocardium. SYN: anulus fibrosus (1) [TA] , anulus fibrosus dexter/sinister cordis, coronary tendon, fibrous r. (1) , Lower r..
Schatzki r. a contraction r. or incomplete mucosal diaphragm in the lower third of the esophagus, which is occasionally symptomatic.
Schwalbe r. SYN: anterior limiting lamina.
scleral r. the appearance of the sclera adjacent to the optic disk when the retinal pigment epithelium does not extend to the optic nerve.
signet r. the early stage of trophozoite development of the malaria parasite in the red blood cell; the parasite cytoplasm stains blue around its circular margin, and the nucleus stains red in Romanowsky stains, while the central vacuole is clear, giving the ringlike appearance.
r. of Soemmerring a mass of lenticular fibers enclosed between the anterior and posterior portion of the lenticular capsule, leaving the pupillary area relatively free.
subcutaneous r. SYN: superficial inguinal r..
superficial inguinal r. [TA] the slitlike opening in the aponeurosis of the external oblique muscle of the abdominal wall through which the spermatic cord (round ligament in the female) and inguinal hernias emerge from the inguinal canal. SEE ALSO: aponeurosis of external oblique muscle. SYN: anulus inguinalis superficialis, external inguinal r., subcutaneous r..
tonsillar r. SYN: pharyngeal lymphatic r..
tracheal r. SYN: tracheal cartilages, under cartilage.
tympanic r. [TA] in the fetus, a more or less complete bony r. at the medial end of the cartilaginous external acoustic meatus, to which is attached the tympanic membrane. SYN: anulus tympanicus, tympanic bone.
umbilical r. [TA] an opening in the linea alba through which pass the umbilical vessels in the fetus; in young embryos it is relatively nearer to the pubis, but gradually ascends to the center of the abdomen; it is closed in the adult, its site being indicated by the umbilicus or navel. SYN: anulus umbilicalis, canalis umbilicalis.
vascular r. anomalous arteries (aortic arches) congenitally encircling the trachea and esophagus, at times producing pressure symptoms.
Vieussens r. SYN: limbus fossae ovalis.
Vossius lenticular r. a r.-shaped opacity found on the anterior lens capsule after contusion of the eye, due to pigment and blood.
Waldeyer throat r. SYN: pharyngeal lymphatic r..
Zinn r. SYN: common tendinous r. of extraocular muscles.

Ringer
Ringer

Sydney, English physiologist, 1835–1910. See R. injection, R. solution, lactated R. injection, Krebs-R. solution, Locke-R. solution, R. lactate.

ring-knife
ring-knife (ring-nif)

A circular or oval ring with internal cutting edge, on the model of the carpenter's spoke-shave, for shaving off tumors in the nasal and other cavities. SYN: spoke-shave.

ringworm
ringworm (ring′werm)

SYN: tinea.
r. of beard SYN: tinea barbae.
black-dot r. tinea capitis due most commonly to Trichophyton tonsurans or T. violaceum.
r. of body SYN: tinea corporis.
crusted r. SYN: favus.
r. of foot SYN: tinea pedis.
honeycomb r. SYN: favus.
r. of nails SYN: onychomycosis.
Oriental r. SYN: tinea imbricata.
r. of scalp SYN: tinea capitis.
scaly r. SYN: tinea imbricata.
Tokelau r. SYN: tinea imbricata. [Tokelau Islands in S. Pacific Ocean]

Rinne
Rinne

Friedrich Heinrich A., German otologist, 1819–1868. See R. test.

Riolan
Riolan

Jean, French anatomist and botanist, 1577–1657. See R. anastomosis, R. arc, R. arcades, under arcade, R. bones, under bone, R. bouquet, R. muscle.

RIP
RIP

Abbreviation for radioimmunoprecipitation.

riparian
riparian (ri-par′e-an, ri-)

Relating to a ripa; marginal.

Ripault
Ripault

Louis H.A., French physician, 1807–1856. See R. sign.

ripening
ripening (ri′pen-ing)

Denoting progressive oxidation of dye solutions, as in the r. of hematoxylin solutions to hematein or of methylene blue to azure dyes.

Ripstein
Ripstein

Charles B., 20th century U.S. surgeon. See R. operation.

RISA
RISA

Abbreviation for radioiodinated serum albumin.

risk
risk

The probability that an event will occur.
attributable r. the rate of a disease or other outcome in exposed individuals that can be attributed to the exposure.
competing r. an event that removes a subject from being at r. for an outcome under investigation.
empiric r. r. that is based on empiric evidence alone, without any appeal to formal theory or surmise.
radiation risks the risks to health posed by exposure to radiation. Sources of exposure are both natural and artificial ( e.g., medical and occupational). See background radiation.Excessive exposure to ionizing radiation is associated with increased r. of malignant diseases, particularly of the skin and blood-forming organs; increased r. of abnormal variation in reproductive cells, with the possibility of abnormality in offspring; and increased r. of fetal abnormality from maternal exposure during early pregnancy. For most people, natural sources account for the bulk of received radiation, with artificial sources adding only a small percentage to the average annual dose. Public perception of the hazards of radiation is often at odds with scientific positions on the subject. Equivocal research results (as in attempts to assess the added cancer r. posed by mammograms) have contributed to public fears. Some studies have concluded that, whether or not public fears of nuclear power plants are justified, the added stress caused by such fears in itself constitutes a threat to health.
recurrence r. r. that a disease will occur elsewhere in a pedigree, given that at least one member of the pedigree (the proband) exhibits the disease.
relative r. the ratio of the r. of disease among those exposed to a r. factor to the r. among those not exposed.

Risley
Risley

Samuel D., U.S. ophthalmologist, 1845–1920. See R. rotary prism.

risorius
risorius (ri-sor′e-us)

See r. (muscle). [L. risor, a laughter, fr. rideo, pp. risus, to laugh]

RIST
RIST

Abbreviation for radioimmunosorbent test.

ristocetin
ristocetin (ris-to-se′tin)

An antibiotic produced by the fermentation of Amycolatopsis orientalis lurida, comprising two substances; r. A and r. B; it is useful against staphylococcic and enterococcic infections refractory to other antibiotics.

risus risus (ri′sus)

Laughter. [laughter]
r. caninus (ri′sus ka-ni′nus) the semblance of a grin caused by facial spasm, seen especially in tetanus but also in some kinds of poisoning. SYN: canine spasm, r. sardonicus, sardonic grin, trismus sardonicus. [L. r., laugh + caninus, doglike]
r. sardonicus (sar-don′i-kus) SYN: r. caninus. [L. r., laughter, + sardonicus, fr. G. sardanios, scornful, infl. by sardonios, Sardinian, ref. to effects of Strychnos nux-vomica, poisonous herb fr. Sardinia]

Ritgen
Ritgen

Ferdinand A.M.F. von, German obstetrician, 1787–1867. See R. maneuver.

ritodrine
ritodrine (ri′to-dren)

A sympathomimetic agent with β₂-adrenergic stimulant actions, used as a uterine relaxant.

Ritter
Ritter

Johann W., German physicist, 1776–1810. See R. opening tetanus, R.-Rollet phenomenon.

ritual
ritual (rich′oo-al)

In psychiatry and psychology, any psychomotor activity ( e.g., morbid handwashing) performed by a person to relieve anxiety or forestall its development; typically seen in obsessive-compulsive disorder. [L. ritualis, fr. ritus, rite]

rituximab
rituximab (rit-uks′im-ab)

Monoclonal antibody used in the treatment of non-Hodgkin lymphoma.

rivalry
rivalry (ri′val-re)

Competition between two or more individuals or entities for the same object or goal. [L. rivalis, competitor, rival]
binocular r. alteration in perception of portions of the visual field when the two eyes are simultaneously and rapidly exposed to targets containing dissimilar colors or borders.
r. of retina simultaneous excitation of corresponding retinal areas of each eye by stimuli that differ in size, color, shape, or luminance, making fusion impossible.
sibling r. jealous competition among children, especially for the attention, affection, and esteem of their parents; by extension, a factor in both normal and abnormal competitiveness throughout life.

Rivea corymbosa
Rivea corymbosa (riv′e-a ko-rim-bo′sa)

Mexican bindweed, a plant of the family Convolvulaceae, the seeds of which were used in ceremonies by Aztec Indians in Mexico and contain lysergic acid amide, isolysergic acid, lysergic acid monoethylamide, chanoclavine, and other indole alkaloids; several hundred seeds must be ingested to produce hallucinatory and euphoric effects. SYN: morning glory (2) .

Riverius Riverius

See Rivière.

Rivero-Carvallo
Rivero-Carvallo

José Manuel, Mexican cardiologist, *1905. See Carvallo sign, Rivero-Carvallo effect.

Rivers
Rivers

William H., English physician, 1864–1922. See R. cocktail.

Rivière
Rivière, Riverius

Lazare (Lazarus), French physician, 1589–1655. See R. salt.

Rivinus Rivinus (Latin form of Bachmann)

August Q., German anatomist, 1652–1723. See R. canals, under canal, R. ducts, under duct, R. gland, R. incisure, R. membrane, R. notch.

rivus lacrimalis
rivus lacrimalis (ri′vus lak-ri-ma′lis) [TA]

SYN: lacrimal pathway. [L. rivus, stream, + Mediev. L. lacrimalis, fr. L. lacrima, a tear]

riziform
riziform (riz′i-form)

Resembling rice grains. [Fr. riz, rice]

RLL
RLL

Abbreviation for right lower lobe (of lung).

RLQ
RLQ

Abbreviation for right lower quadrant (of abdomen).

RMA
RMA

Abbreviation for right mentoanterior position.

RML
RML

Abbreviation for right middle lobe (of lung).

RMP
RMP

Abbreviation for right mentoposterior position.

RMT
RMT

Abbreviation for right mentotransverse position.

RMV
RMV

Abbreviation for respiratory minute volume.

R.N.
R.N.

Abbreviation for registered nurse.

Rn
Rn

Symbol for radon.

RNA
RNA

Abbreviation for ribonucleic acid.For terms bearing this abbreviation, see subentries under ribonucleic acid.

RNase
RNase

Abbreviation for ribonuclease.For terms bearing this abbreviation, see subentries under ribonuclease.

RNase D
RNase D

Abbreviation for ribonuclease D.

RNA splicing
RNA splicing

SYN: splicing (2) .

RNP
RNP

Abbreviation for ribonucleoprotein.

ROA
ROA

Abbreviation for right occipitoanterior position.

Roach
Roach

F. Ewing, U.S. prosthodontist, 1868–1960. See R. clasp.

Roaf
Roaf

R. See R. syndrome.

Robert
Robert

Heinrich, L.F., German gynecologist, 1814–1878. See R. pelvis.

Roberts
Roberts

J.B., 20th century U.S. physician. See R. syndrome.

Robertshaw
Robertshaw

Frank L., 20th century English anesthesiologist. See R. tube.

Robertson
Robertson

See Argyll R..

Robin
Robin

Pierre, French pediatrician, 1867–1950. See Pierre R. syndrome.

Robin
Robin

Charles P., French physician, 1821–1885. See Virchow-R. space.

Robinow
Robinow

Meinhard, U.S. physician, *1909. See R. dwarfism, R. syndrome.

Robinson
Robinson

Brian F., 20th century British cardiologist. See R. index.

Robison
Robison

Robert, English chemist, 1884–1941. See R. ester, R. ester dehydrogenase, R.-Embden ester.

Robles
Robles

Rudolfo (Valverde), Guatemalan dermatologist, 1878–1939.

robotic
robotic (ro-bot′ik)

Pertaining to or characteristic of a robot, an automatic mechanical device designed to duplicate a human function without direct human operation. [Czech robot, robot, fr. robota, drudgery, + -ic]

Robson Robson

See Mayo-R..

robustness
robustness (ro-bust′ness)

In statistics, the degree to which the probability of drawing a wrong conclusion from the test result is not seriously affected by moderate departures from the assumptions implicit in the model on which the test is based. [L. robustus, hale, strong, fr. robur, oak, hard, strong]

ROC
ROC

Acronym for receiver operating characteristic, an analytic expression of diagnostic accuracy. See R. curve.

roccellin
roccellin (rok′sel-in) [C.I. 15620]

SYN: archil.

Rochalimaea
Rochalimaea (ro-cha-li′ma-a)

Former name for Bartonella. [H. da Rocha-Lima, Brazilian microbiologist]
R. henselae See Bartonella henselae.
R. quintana See Bartonella quintana.

rod
rod (rod)

1. A slender cylindric structure or device. 2. The photosensitive, outward-directed process of a rhodopsin-containing r. cell in the external granular layer of the retina; many millions of such rods, together with the cones, form the photoreceptive layer of rods and cones. SYN: r. cell of retina. [A.S. r.]
analyzing r. a device used with a surveyor to determine the relative positions of parallel surfaces and undercuts when designing removable partial dentures.
Auer rods SYN: Auer bodies, under body.
basal r. SYN: costa (2) .
Corti rods SYN: pillar cells, under cell.
enamel rods SYN: prismata adamantina, under prisma.
germinal r. SYN: sporozoite.
Maddox r. a glass r., or a series of parallel glass rods, that converts the image of a light source into a streak of light perpendicular to the axis of the r.. The position of this streak in relation to the image of the light source seen by the fellow eye indicates the presence and amount of heterophoria.
surgical r. a cylindric implant, usually composed of metal, used to align and internally fix fractures of long bones. SEE ALSO: nail, pin.

Rodentia
Rodentia (ro-den′she-a)

The rodents; the largest order of placental mammals (class Eutheria), all possessing one pair of chisel-like upper incisors for gnawing and flat-crowned premolars and molars for grinding; it includes the mice, rats, guinea pigs, squirrels, beavers, and many more. [Mod. L., fr. L. rodo, pres. p. rodens, to gnaw]

rodenticide
rodenticide (ro-den′ti-sid)

An agent lethal to rodents. [rodent + L. caedo, to kill]

Roentgen
Roentgen

Wilhelm K., German physicist and Nobel laureate, 1845–1923. Discovered x-rays in November, 1895; awarded Nobel Prize in Physics in 1901 for his discovery. See r., r. ray.

roentgen
roentgen (R, r) (rent′gen, rent′chen)

The international unit of exposure dose for x-rays or gamma rays; that quantity of radiation that will produce in 1 cc or 0.001293 g of air at STP, 2.08 × 10⁹ ions of both signs, each totaling 1 electrostatic unit (e.s.u.) of charge; in the MKS system this is 2.58 × 10⁻⁴ coulombs per kg of air. [W. K. R.]
r.-equivalent-man (rem) a unit of dose equivalent to that quantity of ionizing radiation of any type that produces in humans the same biologic effect as 1 rad of x-rays or gamma rays; the number of rems is equal to the absorbed dose, measured in rads, multiplied by the quality factor of the radiation in question. 100 rem = 1 Sv.
r.-equivalent-physical obsolete unit of measurement; that quantity of ionizing radiation of any kind that, upon absorption by living tissue, produces an energy gain per gram of tissue equivalent to that produced by 1 rad of x-rays or gamma-rays. See rad.

roentgenkymogram
roentgenkymogram (rent′gen-ki′mo-gram)

A record of the heart's movements taken with the roentgenkymograph.

roentgenkymograph
roentgenkymograph (rent′gen-ki′mo-graf)

An apparatus for recording the movements of the heart and great vessels or of the diaphragm on a single film. It consists of a lead sheet called the grid in which are cut horizontal or vertical slits, typically less than 1 mm wide, spaced 1–2 cm apart. During an x-ray exposure lasting as long as several cardiac or respiratory cycles, the grid or the film is moved vertically to record cardiac motion or horizontally for diaphragm motion.

roentgenkymography
roentgenkymography (rent′gen-ki-mog′ra-fe)

An obsolete technique involving the recording of movements of the heart by means of the roentgenkymograph.

roentgenogram
roentgenogram (rent′gen-o-gram)

SYN: radiograph.

roentgenograph
roentgenograph (rent′gen-o-graf)

SYN: radiograph.

roentgenography
roentgenography (rent′ge-nog′ra-fe)

SYN: radiography.

roentgenologist
roentgenologist (rent′gen-ol′o-jist)

A person skilled in the diagnostic or therapeutic application of roentgen rays; a radiologist.

roentgenology
roentgenology (rent′gen-ol′o-je)

The study of roentgen rays in all their applications. Radiology is the preferred term in the context of medical imaging.

roentgenometer
roentgenometer (rent′ge-nom′e-ter)

SYN: radiometer.

roentgenometry
roentgenometry (rent-ge-nom′e-tre)

Measurement of an administered therapeutic or diagnostic dose and the penetrating power of x-rays. SYN: x-ray dosimetry.

roentgenoscope
roentgenoscope (rent′gen-o-scop)

Obsolete term for fluoroscope.

roentgenoscopy
roentgenoscopy (rent-gen-os′ko-pe)

Obsolete term for fluoroscopy.

roentgenotherapy
roentgenotherapy (rent′gen-o-thar′a-pe)

Obsolete term for radiotherapy.

roetheln
roetheln

See röteln.

Roger
Roger

Georges Henri, French physiologist, 1860–1946. See R. reflex.

Roger
Roger

Henri L., French physician, 1809–1891. See R. disease, R. murmur, bruit de R., maladie de R..

Rogers
Rogers

Oscar H., U.S. physician, 1857–1941. See R. sphygmomanometer.

Rohr
Rohr

Karl, Swiss embryologist and gynecologist, *1863. See R. stria.

Röhrer index
Röhrer index

See under index.

Rokitansky
Rokitansky

Karl Freiherr von, Austrian pathologist, 1804–1878. See R. disease, R. hernia, R.-Aschoff sinuses, under sinus, Mayer-R.-Küster-Hauser syndrome.

rolandic rolandic (ro-lan′dik)

Relating to or described by Luigi Rolando.

Rolando
Rolando

Luigi, Italian anatomist, 1773–1831. See R. angle, R. area, R. cells, under cell, R. column, rolandic epilepsy, R. gelatinous substance, R. tubercle, fissure of R..

role
role (rol)

The pattern of behavior that a person exhibits in relationship to significant persons in his or her life; it has its roots in childhood and is influenced by significant people with whom the person has or had primary relationships. [Fr.]
complementary r. a r. in which the behavior pattern conforms with the expectations and demands of other people.
gender r. the public presentation of gender identity; specifically, everything a person says and does that signals to others or to the self that one is male or female (or androgynous). See sex r., gender identity.
noncomplementary r. a r. that does not conform with the expectations and demands of other people.
sex r. specifically, the pattern of behavior and thought related to sex organs and procreation; but more generally, behavior and thought that is stereotypically classified as belonging to either one sex or the other. See gender r..
sick r. in medical sociology, the familially or culturally accepted behavior pattern or r. which one is permitted to exhibit during illness or disability, including sanctioned absence from school or work and a submissive, dependent relationship to family, health care personnel, and significant others.

role-playing
role-playing

A psychotherapeutic method used in psychodrama to understand and treat emotional conflicts through the enactment or reenactment of stressful interpersonal events. See psychodrama.

rolitetracycline
rolitetracycline (ro′li-tet-ra-si′klen)

A more soluble and less irritating derivative of tetracycline; uses and effectiveness are similar to those of tetracycline, and it may be administered intravenously or intramuscularly, which makes it useful when oral administration of a tetracycline is impossible or impracticable.

roll
roll (rol)

1. A mass or structure in the shape of a r.. 2. The process by which a round entity is moved by a pressure gradient, as a leukocyte moves along a blood vessel wall.
iliac r. a sausage-shaped, often painful, nonfluctuating mass, with convexity to the right, palpable in the left iliac fossa, due to induration of the walls of the sigmoid flexure.
scleral r. SYN: scleral spur.

Roller
Roller

Christian F.W., German neurologist and psychiatrist, 1844–1978. See R. nucleus.

roller
roller (ro′ler)

See r. bandage.

Rolleston
Rolleston

Sir Humphry D., British physician, 1862–1944. See R. rule.

Rollet
Rollet

Alexander, Austrian physiologist, 1834–1903. See R. stroma, Ritter-R. phenomenon.

Romaña
Romaña

Cecilio, Argentinian physician in Brazil, *1899. See R. sign.

Romano
Romano

C., 20th century Italian physician. See R.-Ward syndrome.

Romanowsky
Romanowsky

Dimitri L., Russian physician, 1861–1921. See R. blood stain.

Romberg
Romberg

Moritz H., German physician, 1795–1873. See R. test, R. disease, facial hemiatrophy of R., R. syndrome, R. sign.

rombergism
rombergism (rom′berg-izm)

SYN: Romberg sign.

Römer
Römer

Paul H., German bacteriologist, 1876–1916. See R. test.

rongeur
rongeur (rawn-zher′)

A strong biting forceps for nipping away bone. [Fr. ronger, to gnaw]

R&slash;onne
R&slash;onne

Henning K.T., Danish ophthalmologist, 1878–1947. See R. nasal step.

roof
roof (roof)

A covering or rooflike structure; e.g., a tectorium, tectum, tegmen, tegmentum, integument. [A.S. hrof]
r. of fourth ventricle [TA] SYN: tegmen ventriculi quarti.
r. of mouth SYN: palate.
r. of orbit [TA] formed by the orbital plate of the frontal bone and the lesser wing of the sphenoid bone, the optic canal opens at its posterior limit; an indentation, the fossa for the lacrimal gland, is located in the anterolateral part of the r.. SYN: paries superior orbitae [TA] , superior wall of orbit.
r. of skull SYN: calvaria.
r. of tympanic cavity SYN: tegmental wall of tympanic cavity.
r. of tympanum SYN: tegmen tympani.

roofplate
roofplate (roof′plat)

See roof plate.

rooming-in
rooming-in (room′ing-in)

Placement of newborn with mother, rather than in nursery, during the postpartum hospital stay.

root
root (root) [TA]

1. The primary or beginning portion of any part, as of a nerve at its origin from the brainstem or spinal cord. SYN: radix (1) [TA] . 2. SYN: r. of tooth. 3. The descending underground portion of a plant; it absorbs water and nutrients, provides support, and stores nutrients. For roots of pharmacologic significance not listed below, see specific names. [A.S. rot]
accessory r. of tooth [TA] an anomalous additional tooth r.. SYN: radix accessoria [TA] .
anatomical r. that portion of a tooth extending from the cervical line to its apical extremity.
anterior r. of spinal nerve [TA] the motor r. of a spinal nerve. SYN: radix anterior nervi spinalis [TA] , motor r. of spinal nerve&star, radix motoria nervi spinalis&star, ventral r. of spinal nerve&star, radix ventralis nervi spinalis.
buccal r. of tooth [TA] r. of a multirooted tooth which is located toward the buccal side of the alveolar ridge. SYN: radix buccalis [TA] .
clinical r. of tooth [TA] that portion of a tooth embedded in the investing structures; the portion of a tooth not visible in the oral cavity. SYN: radix clinica dentis [TA] .
cochlear r. of VIII nerve one of the components of the vestibulocochlear nerve; it is made up of the central processes of the bipolar neurons that compose the spiral (cochlear) ganglion in the spiral canal of the modiolus of the bony cochlea; the cochlear r. enters the cranial cavity by passing in fascicles through the spiral foraminous tract at the bottom of the internal auditory meatus; it enters the brainstem through the pontomedullary groove, closely adhering to the caudoventral aspect of the vestibular r., and distributes its fibers to the ventral and dorsal cochlear nuclei in the floor of the lateral recess of the fourth ventricle. SYN: radix inferior nervi vestibulocochlearis.
cranial r. of accessory nerve [TA] the roots of the accessory nerve that arise from the medulla; the nerve fibers of the cranial r. join the intracranial portion of the vagus nerve and are distributed to the pharyngeal plexus, providing the motor innervation of the soft palate (except the tensor veli palati) and the pharynx. SEE ALSO: accessory nerve [CN XI]. SYN: radix cranialis nervi accessorii [TA] , pars vagalis nervi accessorii&star, vagal part of accessory nerve&star, accessory portion of spinal accessory nerve.
Culver r. SYN: leptandra.
dorsal r. of spinal nerve posterior r. of spinal nerve.
facial r. SYN: nerve of pterygoid canal.
r. of facial nerve fibers running from the facial motor nucleus upward to the facial colliculus where they curve around the abducens nucleus and then pass peripherally between the superior olive and sensory nucleus of the trigeminal, to emerge as the facial nerve from the pontomedullary groove. SYN: radix nervi facialis.
r. of foot SYN: tarsus (1) .
hair r. the part of a hair that is embedded in the hair follicle, its lower succulent extremity capping the dermal papilla pili in the deep bulbous portion of the follicle. SYN: radix pili.
inferior r. of ansa cervicalis [TA] fibers from the second and third cervical nerves that pass forward and downward along the internal jugular vein; they contribute to the ansa cervicalis and innervate the infrahyoid muscles. SYN: radix inferior ansae cervicalis [TA] , inferior limb of ansa cervicalis&star, descendens cervicalis.
lateral r. of median nerve [TA] the part of the median nerve arising from the lateral cord of the brachial plexus. SYN: radix lateralis nervi mediani [TA] .
lateral r. of optic tract [TA] the larger division of the posterior end of the optic tract that terminates in the lateral geniculate body. SYN: radix lateralis tractus optici [TA] .
long r. of ciliary ganglion SYN: sensory r. of ciliary ganglion.
r. of lung [TA] all the structures entering or leaving the lung at the hilum, forming a pedicle invested with the pleura; includes the bronchi, pulmonary artery and veins, bronchial arteries and veins, lymphatics, and nerves. SYN: radix pulmonis [TA] .
May apple r. SYN: podophyllum resin.
medial r. of median nerve [TA] the part of the median nerve coming from the medial cord of the brachial plexus. SYN: radix medialis nervi mediani [TA] .
medial r. of optic tract [TA] the smaller division of the posterior end of the optic tract that disappears under the medial geniculate body. SYN: radix medialis tractus optici [TA] .
r. of mesentery [TA] the origin of the mesentery of the small intestine (jejunum and ileum) from the posterior parietal peritoneum; about 9 inches (23 cm) in length, it extends from the duodenojejunal flexure (just to the left of the midline at the L2 vertebral level) to the ileocecal junction (iliac fossa). SYN: radix mesenterii [TA] .
motor r. of ciliary ganglion SYN: parasympathetic r. of ciliary ganglion.
motor r. of spinal nerve anterior r. of spinal nerve.
motor r. of trigeminal nerve [TA] the smaller r. of the trigeminal nerve, composed of fibers originating from the trigeminal motor nucleus and emerging from the pons medial to the much larger sensory r., to join the mandibular nerve; it carries motor and proprioceptive fibers to the muscles derived from the first bronchial (mandibular) arch, including the four muscles of mastication, plus the mylohyoid, anterior belly of the digastric, and the tensores tympani and veli palati. SYN: radix motoria nervi trigemini [TA] , masticator nerve, portio minor nervi trigemini.
r. of nail the proximal end of the nail, concealed under a fold of skin. SYN: radix unguis.
nasociliary r. of ciliary ganglion sensory r. of ciliary ganglion.
nerve r. one of the two bundles of nerve fibers (posterior and anterior roots) emerging from the spinal cord that join to form a single segmental (mixed) spinal nerve; some of the cranial nerves are similarly formed by the union of two roots, in particular the fifth or trigeminal nerve.
r. of nose [TA] the upper least protruding portion of the external nose situated between the two orbits. SYN: radix nasi [TA] .
oculomotor r. of ciliary ganglion parasympathetic r. of ciliary ganglion.
olfactory roots SYN: olfactory striae, under stria.
roots of olfactory tract, lateral and medial the two fiber bands that form the caudal continuation of the olfactory tract that, upon diverging, enclose the olfactory tubercle.
parasympathetic r. of ciliary ganglion [TA] a branch of the oculomotor nerve supplying parasympathetic preganglionic nerve fibers to the ciliary ganglion. SYN: radix parasympathica ganglii ciliaris [TA] , oculomotor r. of ciliary ganglion&star, radix nervi oculomotorii ad ganglion ciliare&star, radix oculomotoria ganglii ciliaris&star, branch of oculomotor nerve to ciliary ganglion, motor r. of ciliary ganglion, radix brevis ganglii ciliaris, short r. of ciliary ganglion.
parasympathetic r. of otic ganglion lesser petrosal nerve.
parasympathetic r. of pelvic ganglia pelvic splanchnic nerves, under nerve.
parasympathetic r. of pterygopalatine ganglion greater petrosal nerve.
parasympathetic r. of submandibular ganglion SYN: chorda tympani.
r. of penis [TA] the proximal attached part of the penis, including the two crura and the bulb. SYN: radix penis [TA] .
posterior r. of spinal nerve [TA] the sensory r. of a spinal nerve, having a dorsal r. ganglion containing the nerve cell bodies of the fibers conveyed by the r. in its distal end. SYN: radix posterior nervi spinalis [TA] , dorsal r. of spinal nerve&star, radix sensoria nervi spinalis&star, sensory r. of spinal nerve&star, radix dorsalis nervi spinalis.
sensory r. of ciliary ganglion [TA] sensory fibers passing from the eyeball through the ciliary ganglion to their cell bodies in the trigeminal ganglion via the nasociliary nerve. SYN: radix sensoria ganglii ciliaris [TA] , nasociliary r. of ciliary ganglion&star, radix nasociliaris ganglii ciliaris&star, ramus communicans nervi nasociliaris cum ganglio ciliari&star, communicating branch of nasociliary nerve with ciliary ganglion, long r. of ciliary ganglion, radix longa ganglii ciliaris.
sensory r. of pterygopalatine ganglion [TA] the ganglionic branches, two short sensory branches of the maxillary nerve in the pterygopalatine fossa, the fibers of which pass through the pterygopalatine ganglion without synapse. SYN: radix sensoria ganglii pterygopalatini [TA] , ganglionic branches of maxillary nerve to pterygopalatine ganglion&star, rami ganglionici nervi maxillaris&star, ganglionic branches of maxillary nerve, nervi pterygopalatini, nervi sphenopalatini, pterygopalatine nerves, rami ganglionares.
sensory r. of spinal nerve posterior r. of spinal nerve.
sensory r. of sublingual ganglion [TA] branch or branches of the lingual nerve conveying sensory fibers to the sublingual ganglion that traverse the ganglion without synapse for distribution to the floor of the mouth. SYN: radix sensoria ganglii sublingualis [TA] , ganglionic branches of lingual nerve to sublingual ganglion&star, ganglionic branches of lingual nerve to submandibular ganglion&star, rami communicantes ganglii sublingualis cum nervo linguali&star.
sensory r. of submandibular ganglion [TA] motor roots of submandibular ganglion; communicating branches between submandibular ganglion and lingual nerve. SYN: radix sensoria ganglii submandibularis [TA] , rami communicantes ganglii submandibularis cum nervo linguali&star, ganglionic branches of lingual nerve.
sensory r. of trigeminal nerve [TA] the large sensory r. of the trigeminal (or fifth cranial) nerve, extending from the semilunar ganglion into the pons through the middle cerebellar peduncle or brachium pontis, immediately lateral to the small motor r.. SYN: radix sensoria nervi trigemini [TA] , portio major nervi trigemini.
short r. of ciliary ganglion SYN: parasympathetic r. of ciliary ganglion.
spinal r. of accessory nerve [TA] originates from the upper five or six cervical spinal segments, emerges from the lateral surface of the spinal cord and ascends through the foramen magnum to join the cranial r.. SYN: radix spinalis nervi accessorii [TA] , pars spinalis nervi accessorii&star, spinal part of accessory nerve&star.
superior r. of ansa cervicalis [TA] the fibers that arise from the first and second cervical nerves, accompany the hypoglossal nerve, then branch off to meet the inferior r. in the ansa cervicalis; they innervate the infrahyoid muscles. SYN: radix superior ansae cervicalis [TA] , superior limb of ansa cervicalis&star, descendens hypoglossi, descending branch of hypoglossal nerve.
sympathetic r. of ciliary ganglion [TA] postganglionic fibers, having cell bodies in the superior cervical ganglion, branching from the carotid plexus passing through the ciliary ganglion without synapse to reach the eyeball. SYN: radix sympathica ganglii ciliaris [TA] .
sympathetic r. of otic ganglion [TA] branch arising from the periarterial plexus of the middle meningeal artery, bringing postsynaptic sympathetic fibers from the superior cervical sympathetic ganglion that traverse the ganglion without synapse for distribution to blood vessels within the parotid gland. SYN: radix sympathica ganglii otici [TA] .
sympathetic r. of pterygopalatine ganglion deep petrosal nerve.
sympathetic r. of sublingual ganglion [TA] branch arising from the periarterial plexus of the facial artery, bringing postsynaptic sympathetic fibers from the superior cervical sympathetic ganglion that traverse the ganglion without synapse for distribution to blood vessels of the sublingual gland. SYN: radix sympathica ganglii sublingualis [TA] .
sympathetic r. of submandibular ganglion [TA] branch to the submandibular ganglion composed of postsynaptic sympathetic fibers from the internal carotid plexus conveyed largely by a periarterial plexus of the facial artery. SYN: radix sympathica ganglii submandibularis [TA] , ramus sympathicus (sympatheticus) ad ganglion submandibulare, sympathetic branch to submandibular ganglion.
tegmental r. of tympanic cavity tegmental wall of tympanic cavity.
r. of tongue [TA] the posterior attached portion of the tongue. SYN: radix linguae [TA] , base of tongue.
r. of tooth [TA] that part of a tooth below the neck, covered by cementum rather than enamel, and attached by the periodontal ligament to the alveolar bone. SYN: radix dentis [TA] , radix (2) [TA] , r. (2) [TA] .
roots of trigeminal nerve collective term for the sensory r. of trigeminal nerve and motor r. of trigeminal nerve. SYN: radices nervi trigemini.
tuberous r. a r. that is swollen for food storage; tuberous primary roots occur in aconite, beet, and carrot; tuberous secondary roots occur in plants of the Umbelliferae; and tuberous adventitious roots occur in jalap and sweet potato.
ventral r. of spinal nerve anterior r. of spinal nerve.
vestibular r. vestibular r. of VIII nerve, a collective term for those sensory fibers of the 8th cranial nerve (vestibulocochlear) that originate from the vestibular labyrinth, have their cell bodies of origin in the vestibular ganglion, and function in the sphere of balance and equilibrium; centrally these fibers end primarily in the vestibular nuclei of the brainstem and in the cerebellum. SYN: radix superior nervi vestibulocochlearis, radix vestibularis, vestibular r. of vestibulocochlear nerve.
vestibular r. of vestibulocochlear nerve SYN: vestibular r..

rootlets
rootlets (root′lets)

In neuroanatomy, nerve r. (radicular fila). See filum. SEE ALSO: radicular fila, under filum.

root planing
root planing (plan′ing)

In dentistry, abrading of rough root surfaces to achieve a smooth surface.

ROP
ROP

Abbreviation for right occipitoposterior position.

ropalocytosis
ropalocytosis (ro-pal′o-si-to′sis)

Formation of numerous processes of erythroid cells, which in ultrathin sections appear club-shaped, associated with cytoplasmic vesicles and found in some diseases of the blood. [G. ropalon, club, + kytos, cell, + -osis, condition]

Ropes test
Ropes test

See under test.

Rorschach
Rorschach

Hermann, Swiss psychiatrist, 1884–1922. See R. test.

Rosa
Rosa (ro′za)

A genus of plants including the roses (family Rosaceae); several varieties are the sources of rose oil: R. alba, cottage rose; R. centifolia, the pale rose or cabbage rose (source of official rose oil); R. damascena, damask rose; and R. gallica, red rose or French rose. [L. rose]

rosacea
rosacea (ro-za′she-a)

Chronic vascular and follicular dilation involving the nose and contiguous portions of the cheeks; may vary from mild but persistent erythema to extensive hyperplasia of the sebaceous glands, seen especially in men as rhinophyma and by deep-seated papules and pustules; accompanied by telangiectasia at the affected erythematous sites. SYN: acne r.. [L. rosaceus, rosy]
granulomatous r. papular lesions in r., characterized microscopically by perifollicular granulomas with central necrosis and scattered giant cells. Lupus miliaris disseminatus faciei is probably a form of granulomatous r.. SYN: r.-like tuberculid, tuberculoid r..
hypertrophic r. SYN: rhinophyma.
tuberculoid r. SYN: granulomatous r..

Rosai
Rosai

Juan, U.S. pathologist, b. 1941. See R.-Dorfman disease.

rosanilin
rosanilin (ro-zan′i-lin) [C.I. 42510]

A tris(aminophenyl)methyl compound; together with pararosanilin it is a component of basic fuchsin; also used as an antifungal agent.

rosaprostol
rosaprostol (ro′sa-prost-ol)

A prostaglandin analog with protective properties for the gastric mucosa; similar to misoprostol and also used as an antiulcerative drug.

rosary
rosary (ro′zer-e)

A beadlike arrangement or structure.
rachitic r. a row of beading at the junction of the ribs with their cartilages, often seen in rachitic children. SYN: beading of the ribs.

Roscoe
Roscoe

Sir Henry E., British chemist, 1833–1915. See Bunsen-R. law.

Rose
Rose

Edmund, German physician, 1836–1914. See R. position.

Rose
Rose

Harry M., U.S. microbiologist, *1906. See R.-Waaler test.

rose
rose (roz)

1. Any shrub of the genus Rosa. 2. The petals of Rosa gallica, collected before expanding; used for its agreeable odor. [L. rosa]
r. hips the fruit or berries from wild r. bushes and in particular Rosa canina, R. gallica, R. condita, and R. Rugosa, (family Rosaceae). A rich source of vitamin C (ascorbic acid). SYN: hipberries.
r. oil a volatile oil from Rosa centifolia; used in perfumery and in ointments. SYN: attar of r..

rose bengal
rose bengal (roz′ ben′gal) [C.I. 45440]

The sodium salt of tetraiodotetra-chlorfluorescein, used as a stain for bacteria, as a stain in the diagnosis of keratitis sicca, and in liver function tests.

Rose-Bradford kidney
Rose-Bradford kidney

See under kidney.

rosemary oil
rosemary oil (roz′mar-e)

The volatile oil distilled with steam from the fresh flowering tops of Rosmarinus officinalis (family Labiatae); used as a flavoring and in perfumery.

Rosenbach
Rosenbach

Ottomar, German physician, 1851–1907. See R. law, R. sign, R. test, R.-Gmelin test.

Rosenmüller
Rosenmüller

Johann C., German anatomist, 1771–1820. See R. fossa, R. gland, R. node, R. recess, R. valve, organ of R..

Rosenthal
Rosenthal

Curt, 20th century German psychiatrist. See Melkersson-R. syndrome.

Rosenthal
Rosenthal

Friedrich C., German anatomist, 1780–1829. See R. canal, R. vein, basal vein of R..

Rosenthaler-Turk reagent
Rosenthaler-Turk reagent

See under reagent.

Rosenthal fiber
Rosenthal fiber

See under fiber.

roseola
roseola (ro-ze′o′la)

A symmetrical eruption of small, closely aggregated patches of rose-red color. It is believed to be caused by human herpesvirus type 6. SEE ALSO: exanthema subitum. SYN: macular erythema. [Mod. L. dim. of L. roseus, rosy]
epidemic r. SYN: rubella.
idiopathic r. r. not occurring as a symptom of a recognized general disease.
r. infantilis, r. infantum SYN: exanthema subitum.
syphilitic r. usually the first eruption of syphilis, occurring 6 to 12 weeks after the initial lesion.

Roser
Roser

Wilhelm, German surgeon, 1817–1888. See R.-Nélaton line.

rosette
rosette (ro-zet′)

1. The quartan malarial parasite Plasmodium malariae in its segmented or mature phase. 2. A grouping of cells characteristic of neoplasms of neuroblastic, neuroectodermal, or ependymal origin; a number of nuclei form a ring from which neurofibrils, which can be demonstrated by silver impregnation, extend to interlace in the center (Homer-Wright r.). 3. Roselike coiling of the uterus among certain pseudophyllidean tapeworms, such as Diphyllobothrium latum. 4. Cells of one type surrounding a cell of another type. [Fr. a little rose]
E r. (ro-zet′) the adherence of erythrocytes to cells. Sheep erythrocytes will adhere spontaneously to human T cells, forming rosettes.
EAC r. indicates the presence of complement receptors. Erythrocytes (E) coated with antibody (A) and complement (C) are incubated with test cells; if the test cells have complement receptors, the EAC will adhere to these cells, forming rosettes.
Homer-Wright rosettes pseudorosettes formed by the arrangement of tumor cells around an area of fibrillarity, evidence of neuroblastic differentiation in a medulloblastoma or primitive neuroectodermal tumor.
Wintersteiner rosettes rosettes found only in retinal embryonic tumors, formed by a group of columnar cells with a peripheral basement membrane arranged in a radial manner around a central cavity, the spokes corresponding to the photoreceptors.

rosin
rosin (roz′in)

The solid resin obtained after steam distillation of crude balsam from Pinus palustris and from other species of Pinus (family Pinaceae); used in plasters to render them adhesive and also in ointments to render them locally stimulating. SYN: colophony, resin (2) .

Ross
Ross

Donald N., Br. cardiac surgeon, * 1922; introduced aortic valve replacement using a pulmonic valve autograft. See R. procedure.

Ross
Ross

Sir George W., Canadian physician, 1841–1931. See R.-Jones test.

Ross
Ross

Sir Ronald, English physician and Nobel laureate, 1857–1932. See R. cycle.

Rossolimo
Rossolimo

Grigoriy I., Russian neurologist, 1860–1928. See R. reflex, R. sign.

rostellum
rostellum (ros-tel′um)

The anterior fixed or invertible portion of the scolex of a tapeworm, frequently provided with a row (or several rows) of hooks. [L. dim. of rostrum, a beak]
armed r. r. with one or more rows of hooks.
unarmed r. r. lacking hooks.

rostrad
rostrad (ros′trad)

1. In a direction toward any rostrum. 2. Situated nearer a rostrum or the snout end of an organism in relation to a specific reference point; opposite of caudad (2). [L. rostrum, beak, + -ad, toward]

rostral
rostral (ros′tral) [TA]

1. Relating to any rostrum or anatomic structure resembling a beak. 2. At the head end. SYN: rostralis [TA] . [L. rostralis, fr. rostrum, beak]

rostralis
rostralis (ros′tra′lis) [TA]

SYN: rostral, rostral. [L. fr. rostrum, beak]

rostrate
rostrate (ros′trat)

Having a beak or hook. [L. rostratus]

rostriform
rostriform (ros′tri-form)

Beak-shaped. [L. rostrum, beak]

rostrum
rostrum, pl .rostrarostrums (ros′trum, -tra) [TA]

Any beak-shaped structure. [L. a beak]
r. corporis callosi [TA] SYN: r. of corpus callosum.
r. of corpus callosum [TA] beak of the corpus callosum, the recurved portion of the corpus callosum passing backward from the genu to the anterior commissure. SYN: r. corporis callosi [TA] .
sphenoidal r. [TA] the anterior projecting part of the body of the sphenoid bone that articulates with the vomer. SYN: r. sphenoidale [TA] , r. of the sphenoid bone.
r. sphenoidale [TA] SYN: sphenoidal r..
r. of the sphenoid bone SYN: sphenoidal r..

ROT
ROT

Abbreviation for right occipitotransverse position.

rot
rot

To decay or putrify. [A.S. rotian]

rotamase
rotamase (ro′ta-maz)

Enzyme capable of altering the rotational conformation of a molecule.

rotamer
rotamer (ro′ta-mer)

An isomer differing from other conformation(s) only in rotational positioning of its parts, such as cis- and trans- forms.

rotameter
rotameter (ro-tam′e-ter)

A device for measuring the flow of gas or liquid; the fluid flowing up through a slightly tapered tube elevates a ball or other weight that partially obstructs the flow, until the wider cross-section allows that flow to pass around the floating obstruction. [L. rota, wheel, + G. metron, measure]

rotation
rotation (ro-ta′shun)

1. Turning or movement of a body around its axis. 2. A recurrence in regular order of certain events, such as the symptoms of a periodic disease. 3. In medical education, a period of time on a particular service or specialty. [L. rotatio, fr. roto, pp. rotatus, to revolve, rotate]
intestinal r. r. of the primitive intestinal loop around an axis formed by the superior mesenteric artery. See malrotation.
molecular r. one-hundredth of the product of the specific r. of an optically active compound and its molecular weight.
off-vertical r. r. about an axis eccentric to the body.
optic r. the change in the plane of polarization of polarized light of a given wavelength upon passing through optically active substances; measured in terms of specific r. by polarimetry, an important tool in chemical structural work, especially on carbohydrates.
specific optic r. ([α]) the arc through which the plane of polarized light is rotated by 1 g of a substance per milliliter of water when the length of the light path through the solution is 1 decimeter, typically using light corresponding to the D line of sodium.

rotator
rotator (ro-ta′ter, -tor)

SYN: r. muscle. See rotatores (muscles), under muscle. [L. See rotation]
medial r. a muscle that turns a part medialward. SEE ALSO: invertor. SYN: intortor.

rotavirus
rotavirus (ro′ta-vi′rus)

A group of RNA viruses (family Reoviridae) wheel-like in appearance that form a genus, Rota virus, which includes the human gastroenteritis viruses (a major cause of infant diarrhea throughout the world). Separated into groups A through F, rotaviruses can infect a number of vertebrates. They are fastidious, and in vitro culture is difficult. SYN: duovirus, gastroenteritis virus type B, infantile gastroenteritis virus, reovirus-like agent. [L. rota, wheel, + virus]

Rotch
Rotch

Thomas M., U.S. physician, 1849–1914. See R. sign.

röteln
röteln, roetheln (ruht′eln)

SYN: rubella. [Ger. little red spots, fr. rot, red, + -el, dim. suffix]

rotenone
rotenone (ro′te-non)

The principal insecticidal component of derris root, Derris elliptica, D. malaccensis, and other species of D., and from Lonchocarpus nicou (family Leguminosae); used externally for the treatment of scabies and infestation with chiggers, and in veterinary medicine for follicular mange and infestation with lice, fleas, and ticks; an inhibitor of the respiratory chain.

Roth
Roth

Moritz, Swiss physician and pathologist, 1839–1914. See R. spots, under spot, vas aberrans of R..

Roth
Roth

Vladimir K., Russian neurologist, 1848–1916. See Bernhardt-R. syndrome.

Roth Roth

See Benedict-R. apparatus.

Rothera
Rothera

Arthur C.H., English biochemist, 1880–1915. See R. nitroprusside test.

Rothia
Rothia (roth′e-a)

A genus of nonmotile, non–spore-forming, non–acid-fast, aerobic to facultatively anaerobic bacteria (family Actinomycetaceae) containing Gram-positive, coccoid, diphtheroid, or filamentous cells; metabolism is fermentative, and glucose fermentation yields primarily lactic acid but no propionic acid. These organisms are normal inhabitants of the human oral cavity and are opportunistic pathogens. The type species is R. dentocariosa. [G. D. Roth]
R. dentocariosa rare cause of infective endocarditis in humans.

Rothmund
Rothmund

August von, German physician, 1830–1906. See R. syndrome, R.-Thomson syndrome.

Rotor
Rotor

Arturo B., 20th century Philippine internist. See R. syndrome.

rotoscoliosis
rotoscoliosis (ro′to-sko-le-o′sis)

Combined lateral and rotational deviation of the vertebral column. [L. roto, to rotate, + G. skoliosis, crookedness]

rototome
rototome (ro′to-tom)

A rotating cutting instrument used in arthroscopic surgery.

rotoxamine
rotoxamine (ro-tok′sa-men)

Active isomer of carbinoxamine; an antihistaminic.

Rouget
Rouget

Charles M.B., French physiologist, 1824–1904. See R. muscle, R.-Neumann sheath.

Rouget
Rouget

Antoine D., 19th century French physiologist. See R. bulb.

rough
rough (ruf)

Not smooth; denoting the irregular, coarsely granular surface of a certain bacterial colony type.

roughage
roughage (ruf′ij)

Anything in the diet, e.g., bran, serving as a bulk stimulant of intestinal peristalsis.

Roughton
Roughton

Francis J.W., British scientist, 1899–1972. See R.-Scholander apparatus, R.-Scholander syringe.

Rougnon de Magny
Rougnon de Magny

Nicholas F., French physician, 1727–1799. See Rougnon-Heberden disease.

rouleau
rouleau, pl .rouleaux (roo-lo′)

An aggregate of erythrocytes stacked like a pile of coins. R. formation commonly indicates an increase in plasma immunoglobulin. [Fr. spool, cylinder, fr. rouler, to roll, fr. L.L. rotulo, fr. rota, wheel]

roundworm
roundworm (rownd′werm)

A nematode member of the phylum Nematoda, commonly confined to the parasitic forms.

Rous
Rous

F. Peyton, U.S. pathologist and Nobel laureate, 1879–1970. See R. sarcoma, R. sarcoma virus, R. tumor, R.-associated virus.

Roussy
Roussy

Gustave, French pathologist, 1874–1948. See R.-Lévy disease, R.-Lévy syndrome, Dejerine-R. syndrome.

Rouviere
Rouviere

Henri, French anatomist and embryologist, *1875. See node of R..

Roux
Roux

Philibert J., French surgeon, 1780–1854. See R. method.

Roux
Roux

Pierre P.E., French bacteriologist, 1853–1933. See Ro spatula, R. stain.

Roux
Roux

César, Swiss surgeon, 1857–1934. See R.-en-Y anastomosis, R.-en-Y operation.

Rovsing
Rovsing

Niels T., Danish surgeon, 1862–1927. See R. sign.

RPF
RPF

Abbreviation for renal plasma flow. See effective renal plasma flow.

R.Ph.
R.Ph.

Abbreviation for Registered Pharmacist.

rpm
rpm

Abbreviation for revolutions per minute.

RPO
RPO

1. Abbreviation for right posterior oblique, a radiographic projection. 2. Abbreviation for radiation protection officer.

R.Q.
R.Q.

Abbreviation for respiratory quotient.

-rrhagia -rrhagia

Excessive or unusual discharge; hemorrhage. [G. rhegnymi, to burst forth]

-rrhaphy -rrhaphy

Surgical suturing. [G. rhaphe, suture]

-rrhea -rrhea

A flowing; a flux. [G. rhoia, a flow]

-rrhoea -rrhoea

See -rrhea.

rRNA
rRNA

Abbreviation for ribosomal ribonucleic acid.

RSA
RSA

Abbreviation for right sacroanterior position.

RSD
RSD

Abbreviation for reflex sympathetic dystrophy.

RSP
RSP

Abbreviation for right sacroposterior position.

RST
RST

Abbreviation for right sacrotransverse position.

RSV
RSV

Abbreviation for Rous sarcoma virus; respiratory syncytial virus.

RT
RT, rt

Abbreviation for room temperature.

RT3
RT₃

Symbol for reverse triiodothyronine.

rTMP
rTMP

Abbreviation for ribothymidylic acid.

RT-PCR
RT-PCR

Abbreviation for reverse transcriptase polymerase chain reaction.

RU-486
RU-486

SYN: mifepristone.

Ru
Ru

Symbol for ruthenium.

rub
rub (rub)

Friction encountered in moving one body in contact with another.
friction r. SYN: friction sound.
pericardial r., pericardial friction r. SYN: pericardial friction sound.
pleural r. friction r. sound caused by inflammation of the pleura. SYN: pleural friction r., pleural rale.
pleural friction r. SYN: pleural r..
pleuritic r. a friction sound produced by the rubbing together of the roughened surfaces of the costal and visceral pleurae.

Rubarth
Rubarth

Sven, Swedish veterinarian, *1905. See R. disease virus.

rubber
rubber (rub′er)

The prepared inspissated milky juice of Hevea brasiliensis and other species of Hevea (family Euphorbiaceae), known in commerce as pure Para r.; used in the manufacture of various plasters, tissues, bandages, etc.

rubber policeman
rubber policeman

See policeman.

rubeanic acid
rubeanic acid (roo′be-an-ik)

Dithiooxamide, which forms complete dark greenish-black complexes with copper in alkaline ethanolic solution; used histochemically for demonstrating pathologic copper deposits, as in Wilson disease; also reacts with cobalt and nickel.

rubedo
rubedo (roo-be′do)

A temporary redness of the skin. [L. redness, fr. ruber, red]

rubefacient
rubefacient (roo-be-fa′shent)

1. Causing a reddening of the skin. 2. A counterirritant that produces erythema when applied to the skin surface. [L. rubi-facio, fr. ruber, red, + facio, to make]

rubefaction
rubefaction (roo-be-fak′shun)

Erythema of the skin caused by local application of a counterirritant. [see rubefacient]

rubella
rubella (roo-bel′a)

An acute but mild exanthematous disease caused by r. virus (Rubivirus family Togaviridae), with enlargement of lymph nodes, but usually with little fever or constitutional reaction; a high incidence of birth defects in children results from maternal infection during the first trimester of fetal life (congenital r. syndrome). SYN: epidemic roseola, German measles, röteln, roetheln, third disease, three-day measles. [L. rubellus, fem. -a, reddish, dim. of ruber, red]

rubellin
rubellin (roo-bel′in)

A cardiac glycoside with a digitalis-like action, obtained from Urginia rubella (family Liliaceae).

rubeola
rubeola (roo-be′o-la, -be-o′la)

A term used for measles; not to be confused with rubella. [Mod. L. dim. of ruber, red, reddish]

rubeosis
rubeosis (roo-be-o′sis)

Reddish discoloration, as of the skin. [L. ruber, red, + G. -osis, condition]
r. iridis diabetica neovascularization of the anterior surface of the iris in diabetes mellitus.

rubescent
rubescent (roo-bes′ent)

Reddening. [L. rubesco, pr. p. rubescens, to become red]

rubidium
rubidium (Rb) (roo-bid′e-um)

An alkali element, atomic no. 37, atomic wt. 85.4678; its salts have been used in medicine for the same purposes as the corresponding sodium or potassium salts. [L. rubidus, reddish, dark red, fr. rubeo, to be red]

rubidomycin (daunorubicin)
rubidomycin (daunorubicin) (roo-bid′o-mi-sin)

An antibiotic used as an antineoplastic particularly in acute leukemias; similar to doxorubicin in antitumor activity and in exhibiting cumulative cardiotoxicity.

Rubin
Rubin

Isidor C., U.S. gynecologist, 1883–1958. See R. test.

rubin S
rubin S, rubine (roo′bin, ben) [C.I. 42685]

SYN: acid fuchsin.

Rubinstein
Rubinstein

Jack H., U.S. child psychiatrist and pediatrician, *1925. See R.-Taybi syndrome.

Rubivirus
Rubivirus (roo′bi-vi′rus)

A genus of viruses (family Togaviridae) that includes the rubella virus. [rubella + virus]

Rubner
Rubner

Max, German hygienist and biochemist, 1854–1932. See R. laws of growth, under law, R. test.

rubor
rubor (roo′bor)

Redness, as one of the four signs of inflammation (r., calor, dolor, tumor) enunciated by Celsus. [L.]

rubratoxin
rubratoxin (roo-bra-tok′sin)

A mycotoxin produced by Penicillium rubrum and P. purpurogenum, which form readily on cereal grains; responsible for outbreaks of toxicosis in the U.S.

rubredoxins
rubredoxins (roo-bre-dok′sinz)

Ferredoxins without acid-labile sulfur and with the iron in a typical mercaptide coordination.

rubriblast
rubriblast (roo′bri-blast)

SYN: pronormoblast. [L. ruber, red, + G. blastos, germ]
pernicious anemia type r. SYN: promegaloblast. See erythroblast.

rubric
rubric

Section or chapter heading, used with reference to groups of diseases, as in ICD. [M.E. rubrike, title or heading in red, fr. L. ruber, red]

rubricyte
rubricyte (roo′bri-sit)

Polychromatic normoblast. See erythroblast. [L. ruber, red, + kytos, cell]

rubrospinal
rubrospinal (roo′bro-spi′nal)

Relating to the nerve fibers passing from the red nucleus to the spinal cord: the r. tract [TA].

Rubulavirus
Rubulavirus (roo-boo′la-vi-rus)

A genus in the family Paramyxoviridae; causes mumps. SYN: mumpvirus.

ructus
ructus (ruk′tus)

SYN: eructation. [L. fr. ructo, pp. -atus, to belch]

Rud
Rud

Einar, Danish physician, *1892. See R. syndrome.

rudiment
rudiment (roo′di-ment)

1. An organ or structure that is incompletely developed. 2. The first indication of a structure in the course of ontogeny. SYN: rudimentum. [L. rudimentum, a beginning, fr. rudis, unformed]

rudimentary
rudimentary (roo-di-men′tar-e)

Relating to a rudiment. SYN: abortive (2) .

rudimentum
rudimentum, pl .rudimenta (roo′di-men′tum, -ta)

SYN: rudiment, rudiment. [L.]
r. hippocampi indusium griseum.

ruff
ruff (ruf)

A collar or ruffle.
pupillary r. the dark-brown, wrinkled rim of the normal pupil, which is the posterior pigment epithelium of the iris showing itself at the pupillary margin.

Ruffini
Ruffini

Angelo, Italian histologist, 1864–1929. See R. corpuscles, under corpuscle, flower-spray organ of R..

rufous
rufous (roo′fus)

Having a reddish complexion and red hair. SYN: erythristic. [L. rufus, reddish]

ruga
ruga, pl .rugae (roo′ga, roo′ge) [TA]

A fold, ridge, or crease; a wrinkle. [L. a wrinkle]
rugae of gallbladder mucosal folds of gallbladder, under fold.
gastric rugae gastric folds, under fold.
r. gastrica SYN: gastric folds, under fold.
r. palatina SYN: transverse palatine fold.
rugae of stomach SYN: gastric folds, under fold.
rugae of vagina SYN: vaginal rugae.
vaginal rugae [TA] a number of transverse ridges in the mucous membrane of the vagina. SYN: rugae vaginales [TA] , rugae of vagina.
rugae vaginales [TA] SYN: vaginal rugae.
rugae vesicae biliaris mucosal folds of gallbladder, under fold.

rugine
rugine (roo-zhen′)

1. SYN: periosteal elevator. 2. A raspatory. [Fr.]

rugitus
rugitus (roo′ji-tus)

A rumbling sound in the intestines. SEE ALSO: borborygmus. [L. a roaring, fr. rugio, to roar]

rugose
rugose (roo′gos)

Marked by rugae; wrinkled. SYN: rugous. [L. rugosus]

rugosity
rugosity (roo-gos′i-te)

1. The state of being thrown into folds or wrinkles. 2. A ruga.

rugous
rugous (roo′gus)

SYN: rugose.

Ruhemann purple
Ruhemann purple

a blue-violet dye formed in the reaction of ninhydrin with amino acids.

RUL
RUL

Abbreviation for right upper lobe (of lung).

rule
rule (rool)

A criterion, standard, or guide governing a procedure, arrangement, action, etc. SEE ALSO: law, principle, theorem. [O. Fr. reule, fr. L. regula, a guide, pattern]
Abegg r. the tendency of the sum of the maximum positive and maximum negative valence of a particular element to equal 8; e.g., C may have a valence of +4 and −4, O of +6 and −2. Sometimes loosely stated as all atoms have the same number of valences, a consequence of the tendency of valence electron shells to be filled to 8.
American Law Institute r. a test of criminal responsibility (1962): “a person is not responsible for criminal conduct if at the time of such conduct as a result of mental disease or defect he or she lacks substantial capacity either to appreciate the wrongfulness of the conduct or to conform the conduct to the requirements of law.”
r. of bigeminy r. that a ventricular premature beat will follow the beat terminating a long cycle. Sudden prolongation of the ventricular cycle, by changing the refractoriness in the conduction system, causes a peripheral region of bidirectional block to become transiently unidirectional and thus opens potential pathways for reentry to occur.
Chargaff r. in DNA the number of adenine units equals the number of thymine units; likewise, the number of guanine units equals the number of cytosine units.
Clark weight r. an obsolete r. for an approximate child's dose, obtained by dividing the child's weight in pounds by 150 and multiplying the result by the adult dose.
Cowling r. an obsolete r. for a child's dose: that fraction of the adult dose obtained by dividing the age of the child at the nearest birthday by 24.
Durham r. an American test of criminal responsibility (1954) under which an accused person is not held criminally responsible if the unlawful act was the product of mental disease or mental defect.
Gibb phase r. SYN: phase r..
Goriaew r. rarely used term for a r. of a blood counting field by which it is marked off in a series of squares, some of which are again subdivided into 16 smaller ones.
Haase r. the length of the fetus in centimeters, divided by 5, is the duration of pregnancy in months, i.e., the age of the fetus.
Hückel r. the number of depolarized electrons in an aromatic ring is equal to 4n + 2 where n is 0 or any positive integer; l-tyrosine, l-phenylalanine, l-tryptophan, and l-histidine (when the imidazole ring is deprotonated) obey this r..
Ingelfinger r. a principle developed by Franz Ingelfinger for use in the editorial offices of the New England Journal of Medicine, stating that original articles submitted for publication will be reviewed on the understanding that the same information will not be submitted for publication elsewhere during the period of review; has been adopted by many other peer-reviewed medical journals.
isoprene r. the classical, outmoded statement that naturally occurring terpenes are built up by condensation of isoprene units by either a 1-4 linkage (“head to tail”) or a 4-4 linkage (“tail to tail”).
Jackson r. after an epileptic attack, simple and quasiautomatic functions are less affected and more rapidly recovered than the more complex ones.
Le Bel-van't Hoff r. the number of stereoisomers of an organic compound is 2ⁿ, where n represents the number of asymmetric carbon atoms (unless there is an internal plane of symmetry); a corollary of their simultaneously announced conclusions, in 1874, that the most probable orientation of the bonds of a carbon atom linked to four groups or atoms is toward the apexes of a tetrahedron, and that this accounted for all then-known phenomena of molecular asymmetry (which involved a carbon atom bearing four different atoms or groups). SEE ALSO: stereoisomerism.
Liebermeister r. in adult febrile tachycardia, about eight pulse beats correspond to an increase of 1°C.
Meyer-Overton r. because inhalation agents act via the lipid-rich CNS cells, anesthetic potency increases with lipid solubility.
M'Naghten r. the classic English test of criminal responsibility (1843): “to establish a defense on the ground of insanity, it must be clearly proved that, at the time of committing the act, the party accused was laboring under such a defect of reasoning, from disease of the mind, as not to know the nature and quality of the act he was doing, or if he did know it, that he did not know he was doing what was wrong.”
Nägele r. determination of the estimated delivery date by adding 7 days to the first day of the last normal menstrual period, counting back 3 months, and adding 1 year.
New Hampshire r. pioneering American test of criminal responsibility (1871): “if the [criminal] act was the offspring of insanity, a criminal intent did not produce it.”
r. of nines method used in calculating body surface area involved in burns whereby values of 9% or 18% of surface area are assigned to specific regions as follows: Head and neck, 9%; anterior thorax, 18%; posterior thorax, 18%; arms, 9% each; legs, 18% each; and perineum, 1%.
Ogino-Knaus r. the time in the menstrual period when conception is most likely to occur is at about midway between two menstrual periods; fertilization of the ovum is least likely just before or just after menstruation; the basis for the rhythm method of contraception.
r. of outlet an obstetric r. for determining whether the pelvic outlet will permit the passage of a fetus; the sum of the posterior sagittal diameter and the transverse diameter of the outlet must equal at least 15 cm if a normal-sized baby is to pass.
phase r. an expression of the relationships existing between systems in equilibrium: P + V = C + 2, where P is the number of phases, V the variance or degrees of freedom, and C the number of components; it also follows that the variance is V = C + 2 − P. For H₂O at its triple point, V = 1 + 2 − 3 = 0, i.e., both temperature and pressure are fixed. SYN: Gibb phase r..
Prentice r. each centimeter of decentration of a lens results in 1 prism diopter of deviation of light for each diopter of lens power.
Rolleston r. the ideal adult systolic blood pressure is 100 plus half the age, whereas the maximal physiologic pressure is 100 plus the age; of historical interest.
Schütz r. the rate of an enzyme reaction is proportional to the square root of the enzyme concentration; applied specifically to pepsin within a limited range. SYN: Schütz law.
stopping rules in randomized controlled trials and other systematic experiments on human subjects, rules laid down in advance that specify conditions under which the experiment will be terminated, e.g., unequivocal demonstration that one regimen in a randomized controlled trial is clearly superior to the other, or that one is clearly harmful.
Trusler r. for pulmonary artery banding a method that gives guidance as to the correct tightness of the band; the degree of banding for a complex congenital cardiac anomaly with bidirectional shunting less than that for simple ones.
Young r. an obsolete r. to determine a child's dose: 12 is added to the child's age and the sum is divided by the age; the adult dose divided by the figure so obtained gives the proper dose.

ruler
ruler (roo′ler)

A calibrated strip for measuring plane surfaces.
isometric r. a calibrated scale for eliminating distortion in the measurement of plane surfaces.

rum
rum (rum)

A spirit distilled from the fermented juice of the sugar cane.

rum-blossom
rum-blossom (rum-blos′um)

SYN: rhinophyma.

ruminant
ruminant (roo′mi-nant)

An animal that chews the cud, material regurgitated from the rumen for rechewing; e.g., the sheep, cow, deer, or antelope.

rumination
rumination (roo-mi-na′shun)

1. The physiologic process in ruminant animals in which coarse, hastily eaten food is regurgitated from the rumen, thoroughly rechewed, reduced to finer particles, mixed with saliva, and reswallowed. 2. A disorder of infancy characterized by repeated regurgitation of food, with weight loss or failure to thrive, developing after a period of normal functioning. 3. Periodic reconsideration of the same subject. [L. ruminatio, fr. rumino, to chew the cud, think over, fr. rumen, throat]

ruminative
ruminative (roo′min-a-tiv)

Characterized by a preoccupation with certain thoughts and ideas.

Ruminococcus
Ruminococcus (room′e-no-kok′us)

A genus of anaerobic, Gram-positive coccobacilli isolated from the repiratory tract of humans and the intestinal tract of humans and animals. The type species is R. productus, formerly Peptostreptococcus productus.

Rumpel
Rumpel

Theodor, German physician, 1862–1923. See R.-Leede sign, R.-Leede test, R.-Leede phenomenon.

run
run (run)

A group of successive measurements in an analytic process or during a period of time within which the accuracy and precision of the measuring system are expected to be stable. [ME runnen, fr. A. S. rinnan, fr. O.N. rinna]

Rundle Rundle

A.T., British physician. See Richards-R. syndrome.

Runeberg
Runeberg

Johan W., Finnish physician, 1843–1918. See R. formula.

runoff
runoff (run′awf)

Delayed part of the angiographic examination of a vascular bed, to show small artery patency.

runt
runt (runt)

A stunted animal, occurring most frequently in species that give birth to large litters. [A.S.]

rupia
rupia (roo′pe-a)

1. Ulcers of late secondary syphilis, covered with yellowish or brown crusts that have been compared in their appearance to oyster shells. 2. Term occasionally used to designate a very scaly, heaped-up, and secondarily infected psoriatic lesion. [G. rhypos, filth]

rupioid
rupioid (roo′pe-oyd)

Resembling rupia. [G. rhypos, filth (rupia), + eidos, resemblance]

rupture
rupture (rup′choor)

1. SYN: hernia. 2. A solution of continuity or a tear; a break of any organ or other of the soft parts. [L. ruptura, a fracture (of limb or vein), fr. rumpo, pp. ruptus, to break]
artificial membrane r. r. of the membranes induced by use of an amniohook or similar device.
membrane r. r. of the amnionic sac allowing the amnionic fluid to escape through the vagina.
premature membrane r. r. of the membranes before the onset of labor.
preterm membrane r. r. of membranes before term (<37 weeks gestation).
spontaneous membrane r. spontaneous r. of membranes, with or without associated labor.

RUQ
RUQ

Abbreviation for right upper quadrant (of abdomen).

Rushton
Rushton

Martin A., British pathologist, 1903–1970. See R. bodies.

Russell
Russell

Albert L., U.S. dentist, 1905–1985. See R. Periodontal Index.

Russell
Russell

Alexander, 20th century British pediatrician. See R. syndrome, Silver-R. dwarfism, Silver-R. syndrome.

Russell
Russell

Gerald F.M., 20th century English physician. See R. sign.

Russell
Russell

Hamilton, 20th century Australian surgeon. See R. traction.

Russell
Russell

James S. Risien, British physician, 1863–1939. See hooked bundle of R., uncinate bundle of R..

Russell
Russell

Patrick, Irish physician in India, 1727–1805. See R.'s viper venom, R.'s viper.

Russell
Russell

William, Scottish physician, 1852–1940. See R. bodies, under body.

Russell
Russell

William James, English chemist, 1830–1909. See R. effect.

Russell Periodontal Index
Russell Periodontal Index

An index that estimates the degree of periodontal disease present in the mouth by measuring both bone loss around the teeth and gingival inflammation; used frequently in the epidemiologic investigation of periodontal disease.

Rust
Rust

Johann N., German surgeon, 1775–1840. See R. phenomenon.

rusts
rusts (rusts)

Species of Puccinia and other microbes constituting important pathogens of plants, especially cereal grains; they are important allergens for humans when inhaled in large numbers, as in harvesting processes.

ruthenium
ruthenium (Ru) (roo-the′ne-um)

A metallic element of the platinum group; atomic no. 44, atomic wt. 101.07; ¹⁰⁶Ru, with a half-life of 1.020 years, has been used in the treatment of certain eye problems. [Mediev. L. Ruthenia, Russia, where first obtained]

ruthenium red
ruthenium red

Ammoniated r. oxychloride, used in histology and electron microscopy as a stain for certain complex polysaccharides.

rutherford
rutherford (ruth′er-ferd)

Obsolete term for a unit of radioactivity, representing that quantity of radioactive material in which a million disintegrations are taking place per second; 37 r. = 1 mCi. See Becquerel. [Ernest R., British physicist and Nobel laureate, 1871–1937]

rutidosis
rutidosis (roo-ti-do′sis)

SYN: rhytidosis.

rutin
rutin (roo′tin)

A flavonoid obtained from buckwheat, which causes decreased capillary fragility. SYN: rutoside.

rutinose
rutinose (roo′ti-nos)

A disaccharide of d-glucose and l-rhamnose, and a component of rutin.

rutoside
rutoside (roo′to-sid)

SYN: rutin.

Ruysch
Ruysch

Frederik, Dutch anatomist, 1638–1731. See R. membrane, R. muscle, R. tube, R. veins, under vein.

RV
RV

Abbreviation for residual volume.

Ryan
Ryan

Norbert J., 20th century Australian pathologist. See R. stain.

ryanodine
ryanodine (ri-an′o-den)

An alkaloid obtained from Ryania speciosa (family Flacourtiaceae); has a disruptive effect on calcium storage in cardiac and skeletal muscle, where it produces sustained contractions; used as an insecticide.

rye smut
rye smut (ri′ smut′)

SYN: ergot.

Ryle
Ryle

John A., English physician, 1889–1950. See R. tube.