- Imperforate anus
- A congenital malformation (a birth defect) in which the rectum is a blind alley (a cul-de-sac) and there is no anus. The anus is imperforate in the sense that the normal perforation we call the anus is absent. The end of the intestinal tract has not made its way through the skin in the perineal area. Imperforate anus occurs in 1 in about 5,000 newborn babies. It has to be corrected by surgery. Imperforate anus is also known as anal atresia.
* * *partial or complete obstruction of the anus: a condition, discovered at birth, due to failure of the anus to develop normally in the embryo. There are several different types of imperforate anus; these include developmental anal stenosis, persistent anal membrane, and covered anus (due to fused genital folds). If the anal canal fails to develop, the rectum ends blindly above the muscles of the perineum. Most mild cases of imperforate anus can be treated by a simple operation. If the defect is extensive a temporary opening is made in the colon (see colostomy), with later surgical reconstruction of the rectum and anus.
* * *persistence of the anal epithelial plug, so that the anus is closed. The defect is not always complete; sometimes a narrow opening permits passage of contents of the colon. When the anus is completely imperforate, there is simply a dimple in the skin of the perineum; this condition is often associated with atresia of the lower rectum. Called also anal atresia, atresia ani, and proctatresia.
Medical dictionary. 2011.