Releasing stool from the digestive tract requires a series of coordinated contractions of the rectum, as well as a relaxation of the internal and external anal sphincters. Damage to these nerves or muscles can result in pelvic pain, constipation, and/or stool incontinence.
Several diagnostic tests are used to measure the strength of the anal sphincter muscles, the nerves serving the muscles, the mechanics and the rate of transit of the bowel movement.
These tests involve:
- Anorectal manometry: Tests for rectal and anal contractions as well as anorectal sensation and the sphincter reflexes. This test is performed using a small tube inserted into the anus and rectum.
- Pudendal nerve testing: The pudendal nerves run on each side of the pelvis, and controls bladder function, bowel sphincter muscles and sexual function. This test measures the function of the pudendal nerve by using special electrodes on a gloved index finger pressed against the nerve site.
- Anorectal ultrasound: Ultrasound images allow the physician to examine the integrity of the sphincter muscle as well as the rectum.
- Flexible sigmoidoscopy: investigates for rectal and sigmoid diseases.