Anal sphincter electromyography

Anal sphincter electromyography (EMG) and anorectal manometry are simple outpatient tests to assess whether the anal muscle (sphincter) and nerves are working correctly. The anal sphincter is the muscle valve at the opening of the rectum that controls bowel movements. Sometimes the muscles and nerves involved in bowel function can be affected by disease or injury.

What to expect

If you require these tests, you’ll have to fast for a certain number of hours before the procedure and take enemas to clean out your digestive system. During the procedure, a small electrode is inserted a few inches into your rectum. You’ll be asked to alternately relax, squeeze and push (as if you were having a bowel movement). The electrical activity in the muscles will be recorded on a computer, and your doctor will determine if the muscles are behaving as they should. The test takes only about five minutes and you feel minimal discomfort, if any.