Imperforate anus

Alternative names:

anal atresia; anorectal malformations

Definition:

A congenital obstruction of the anal opening.

Causes, incidence, and risk factors:

Imperforate anus is a malformation of the anorectal region that may occur in several forms. The rectum may end in a blind pouch that does not connect with the colon, or it may have openings to the urethra, bladder, or vagina. A condition of stenosis, or narrowing of the anus, or absence of the anus may be present.

The malformations are caused by abnormal development of the fetus, and many are associated with other congenital defects. Imperforate anus is a relatively common congenital malformation that occurs in about 1 out of 5,000 infants.