The rectum is the section of the digestive tract above the anus where stool is held before it passes out of the body through the anus. The anus is the opening at the end of the digestive tract where stool leaves the body. (See also Overview of the Anus and Rectum.)
Prolapse is when an organ slips out of its normal position in the body. Rectal prolapse causes the rectum to turn inside out, so that the rectal lining (rectal mucosa) is visible outside the body as a dark red, moist, fingerlike projection from the anus. Bleeding from the rectum can occur, and an uncontrolled loss of stool (fecal incontinence) is a frequent symptom. Less commonly, the rectum protrudes into the vagina (rectocele). This disorder causes pain only when complications occur or when the prolapse is severe.
A temporary prolapse of only the rectal lining often occurs in otherwise healthy infants, probably when the infant strains during a bowel movement, and is rarely serious. In adults, prolapse of the rectal lining tends to persist and may worsen, so that more of the rectum protrudes.
A complete prolapse of the rectum (sometimes formally called procidentia, but this term can refer to any complete organ prolapse) occurs most often in women older than age 60.
To determine the extent of a prolapse, a doctor examines the area while the person is standing or squatting and straining. By feeling the anal sphincter with a gloved finger, a doctor often detects diminished muscle tone.
In infants and children, a stool softener eliminates the urge to strain. Strapping the buttocks together between bowel movements usually helps the prolapse heal on its own.
In adults, surgery is usually needed to correct the problem. During one kind of abdominal operation (called rectopexy), the entire rectum is lifted, pulled back, and attached to the sacral bone in the pelvis. In another operation, a segment of the rectum is removed, and the remainder of the rectum is stitched to the sacral bone.
For people who are too weak to undergo surgery on the abdomen, surgery on the rectum is preferred.