Common Causes of Incontinence

Bowel function is controlled by 4 factors: rectal sensation, rectal storage capacity, anal sphincter pressure, and bowel habits.

Continence depends on functioning muscles and nerves in and around the rectum and anal canal. At the lower part of the bowels, the sigmoid colon helps to slow the passage of fecal material before it moves into the rectum. The rectum is more elastic than the rest of the bowel so it can stretch to store fecal material. It is surrounded by nerves that detect expansion of the rectum and signal a sensation of urgency to let us know when it is time to have a bowel movement.

Below the the rectum is the area known as the pelvic floor, which is made up of many different muscles. The puborectalis muscle and the external anal sphincter are voluntarily contracted to prevent leakage of stool when you feel fullness in the rectum. The internal anal sphincter is an involuntary muscle that helps to prevent leakage from the rectum. When it's time to have a bowel movement, all these muscles relax so the stool can pass through the anus.

"It can happen with no warning. You don't feel it or know it is there until you see it on your clothes. You are shocked, overwhelmed, and then numb."

Fecal incontinence occurs when something is wrong within the complex mechanisms of the body that maintain continence. Incontinence can result from a variety of factors, such as functional impairment or structural damage to certain muscles or nerves. Fecal incontinence is rarely due to a single factor.

Normal continence depends on the orderly progression of waste material (feces) through the large intestine (colon), rectum, and anus. Muscles and nerves interact to propel waste contents, sense its presence, and permit voluntary storage and elimination.

The pelvic floor plays an important role in maintaining continence. This is a group of muscles that span the underlying surface of the bony pelvis. These muscles not only support the organ systems within the pelvis and lower abdomen but also are necessary to maintain continence. If pelvic floor function is disturbed, normal bowel and bladder control will be disrupted. Incontinence occurs both in individuals with a normal and an abnormal pelvic floor.