Digestive Disease Center

Leading the world in digestive health through innovation and excellence.
M.U.S.C. Digestive Disease Center logoChanging What's Possible®
Ask your doctor
about MUSC

Ano-Rectal Manometry

Ano-rectal manometry measures pressures of the anal sphincter muscles. It also measures how well a person feels different sensations of fullness in the rectum.

A person prepares for the test by using a plain Bisacodyl or Saline enema (for example, Fleets brand) about two to four hours before the test. The enema can be purchased at the drugstore without a prescription. It is important not to eat anything, or drink liquids with caffeine, for about four hours prior to the test.

The person lies on his left side. A small, flexible tube, about the size of a thermometer, is inserted into the rectum. A tiny amount of water drips into the tube while it is connected to a machine that measures pressure.

During the test the nurse asks the person to squeeze, relax, and push. The anal sphincter muscle pressures are measured during each of these maneuvers. To squeeze, the person tightens the sphincter muscles as if trying to prevent anything from coming out. To push, the person strains down as if trying to have a bowel movement.

Ordinarily, the sphincter muscle tightens, and the anal canal pressures increase when the person tries to squeeze. When the person stops squeezing, the muscles should relax, and pressures return to baseline.

When the person pushes, as if having a bowel movement, the sphincter muscles should stay relaxed. This will cause the pressures to stay the same as during rest, or to decrease slightly. If the pressures increase during a push, this may be a sign that the sphincter muscles tighten when pushing. This tightness could contribute to constipation.

Sphincterography and anal manometry show how strong the sphincter muscles are and if they relax as they should during rectal emptying.

Weak muscles that still tighten some can be strengthened with special exercise and treatments. Muscles that do not relax with a push can also be retrained. This is called Pelvic Muscle Retraining and is discussed later.

If the muscles are very weak, some constipation operations may be modified. If a person with colonic inertia has weak sphincters, then to prevent incontinence, the colon may not be shortened as much.

Top of page

Why should I visit the Medical University of South Carolina?


photo of Ashley River Tower
MUSC Ashley River Tower

Your doctor will probably agree with you about your preference to come to MUSC. We offer excellent patient care at a state-of-the-art facility, in a historic setting in the southeastern United States. Our doctors are nationally ranked among the highest in the nation. We employ a multidisciplinary approach to the treatment of patients using the latest technology in medicine.

Come see why MUSC is changing what's possible®.

Read more about why you should choose MUSC for your healthcare needs.

×