Ano-Rectal Manometry

What is ano-rectal manometry?

Ano-rectal manometry is a diagnostic procedure that evaluates rectosphincteric reflex, broken down into pressure of the anal sphincter muscles, sensation of the rectum and neural reflexes required for normal bowel movements.


Ano-rectal manometry may be used to determine the cause or confirm a diagnosis of certain conditions such as:

  • Constipation: Abnormal muscle functions of the sphincter or colon muscles are just some of the possible causes of constipation.
  • Fecal incontinence: Causes such as weak anal sphincter muscles or poor rectum sensation may contribute to fecal incontinence.
  • Hirschsprung’s disease: A congenital condition that affects the large intestine (colon) and causes missing nerve cells in the muscles of part or all of the colon. As a result, newborns and those diagnosed later in childhood with this condition are unable to have bowel movements.

What to expect during the procedure

A machine is attached to a small, flexible tube with a balloon at the end, known as a catheter. The catheter is inserted into the rectum and then slowly withdrawn. During this time, the patient may be asked to squeeze, relax and push to measure muscle pressure of the anal sphincter.

Ano-rectal manometry also works in conjunction with other diagnostic tests, including:

  • Anal sphincter electromyography (EMG): A small plug electrode is inserted into the anal canal, and the patient is then asked to squeeze, relax and push the muscles. The muscle activity is then recorded and assessed.
  • Balloon expulsion test: A small balloon is inserted into the rectum and filled with water. The patient then attempts to excrete it. The time it takes to pass the balloon is recorded and assessed.

To learn more about ano-rectal manometry or to schedule an appointment with one of our specialists, contact us today.

About Ano-rectal Manometry