Anal Manometry

There are two small muscles in the anus (opening from the rectum) that help to control bowel movements. These muscles are known as internal and external sphincters (sfink-ters). (Figures 1 and 2)  

These muscles are normally closed to prevent uncontrolled leakage of bowel movements. To have a bowel movement, these muscles must relax and open at the same time. Anal manometry is a test that studies how these muscles are working.   

Anal ManometryAnal Manometry

  • If your child is old enough, explain to your child how the test is done at a time that you feel is best. The nurse will help you with this.
  • Give your child an enema before the test. You will be instructed how and when to do this.
  • It may be helpful to bring a favorite toy or video to make your child more comfortable during the procedure.
  • Before the procedure, your child will be asked to empty his/her bladder.
  • When a child has anal manometry done at Cincinnati Children's Hospital Medical Center, it will start in the Clinical Research Center (CRC) unit where your child will lie on a table. (Figure 3) If your child is young enough, you may hold him/her in your lap.
  • The doctor and nurse will wear gowns, gloves and plastic glasses.  
  • Your child may be given some medicine to help him/her relax before the test is started.  
  • Your child will need to take off his/her pants and underwear. He/she will be asked to lie on his/her left side on the table. It is important that your child lie still during the test.
  • The doctor will look at the rectum and insert his/her finger to make sure there is no stool in the way and to lubricate the anal canal.
  • A tube with a balloon is inserted into the rectum. (Figure 4) The balloon is slowly inflated to different sizes. The largest size is about the size of a ping-pong ball.
  • The tube is connected to a computer with a graph. The computer records how well the muscles around the anus are working.
  • During the test, parents may be with their child or wait in the waiting area.  
  • The test will take about 45 minutes.
Anal ManometryAnal Manometry

  • The amount of air in the balloon is increased and decreased several times during the test. When the air is increased, your child will feel like he/she has to have a bowel movement. This urge will last only a few seconds and will go away as soon as the amount of air in the balloon is changed.
  • An older child may be asked to tell the doctor or nurse what he/she feels during the test. 
  • Your child may return to a normal diet, play and usual activities.
  • Your child's doctor will discuss the results of the test with you.

Last Updated 10/2012