Fontanelles - sunken
Alternative names:
soft spot - sunken; sunken fontanelles
Definition:
Concave deformity of the "soft spot" in an infant.
Considerations:
The skull is made up of bony plates (7 in the skull itself and 14 in the facial area). They join together to form a solid, bony cavity protecting the brain and supporting the structures of the head. The area where the bones join together are called the sutures.
The bones are not joined together firmly at birth (this allows the head to accommodate passage through the birth canal). The sutures gradually accumulate minerals and harden (this process is called ossification), firmly joining the skull bones together.
In an infant, the spaces where two sutures intersect form a membrane-covered "soft spot" called a fontanelle (fontanel or fonticulus). The fontanelles allow for growth of the skull during an infant's first year.
There are normally 2 fontanelles that are present on a newborn's skull, the anterior and posterior fontanelles. The anterior fontanell is mid-line on top of the head and slightly toward the front. The posterior fontanelle is also mid-line but toward the back of the skull where it turns downward.. Like the sutures, fontanelles gradually ossify and become closed, solid bony areas. The posterior fontanelle (in the back of the head) usually closes by the time an infant is 1 or 2 months old; the anterior fontanelle at the top of the head usually closes sometime between 9 months and 2 years old with an average closure of 18 months.
The fontanelles should feel firm and very slightly concave to the touch. A pulse may be felt in the fontanelle and sometimes is even visible in young infants. A noticeably sunken fontanelle may be a sign that the infant does not have enough fluid in his or her body (dehydrated or dehydration).
Common causes:
Note: There may be other causes of sunken fontanelles. This list is not all inclusive, and the causes are not presented in order of likelihood. The causes of this symptom can include unlikely diseases and medications. Furthermore, the causes may vary based on age and gender of the affected person, as well as on the specific characteristics of the symptom such as location, quality, time course, aggravating factors, relieving factors, and associated complaints.
Home care:
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