In this section
The digestive system carries food through the body after it is eaten. The last parts of the bowel, where stool (poo) exits the body, are called the rectum and anus. The muscles and nerves of the rectum and anus need to work together to control bowel movements (poos). Usually, these muscles are contracted (closed) to prevent soiling (incontinence). When a person has a bowel movement, the muscles must relax together to allow the stool to exit the body.
The function of the muscles in the anus and rectum may be measured using a technique called anorectal manometry. This technique records the pressure waves when the muscles of the rectum and anus contract (squeeze) and relax.
In some children, the muscles of the anus and rectum do not function as they should. This may lead to problems such as constipation or soiling. Anorectal manometry may give us an understanding of how the muscles and nerves are working together.
An anorectal manometry may be performed to help understand the cause of your child’s symptoms, including constipation or soiling. It may also be done before or after surgery.
To perform an anorectal manometry, a thin, flexible tube (catheter) is placed into your child’s bottom. The tube is filled with water, which drips out of small holes along the side of the tube. A machine measures the changes in pressure of the water leaving the tube. This provides a picture of the patterns of contraction and relaxation of the muscles in the anus and rectum.
A small balloon is attached to the end of the manometry catheter. This may be inflated with different amounts of air to mimic stool in the rectum. The pressures in the anus and rectum are measured as the amount of air in the balloon is changed.
A lubricating gel will be put on your child’s bottom. It may feel cold. The doctor may perform a rectal examination to make sure the rectum is empty. The doctor or nurse will insert the flexible tube (catheter) into the rectum. The manometry tube will be connected to a machine, which measures the changes in pressure in the anus and rectum.
The doctor or nurse will perform some special tests. These tests may include:
The machine will record the changes in pressure as each test is done to measure how the muscles and nerves are working. After the study, a doctor or nurse will remove the tube from their bottom.
Your child will need to remain in bed during the procedure. Please bring any activities they enjoy, such as games, books and/or electronic devices. This will help them remain still and distracted during the procedure.
In some cases, your child’s doctor may also recommend other manometry studies (such as colonic manometry) to look at how the rest of your child’s bowel is functioning. If recommended, they will discuss this with you.
For more information, see our fact sheet on
Colonic Manometry .
If your child did not receive an anaesthetic, they will be able to head home after the test and resume their usual activities.
After an anaesthetic, your child will usually be discharged home on the day of the study. Your child must be feeling well, eating and drinking normally, and have no further tests planned for their admission before they are discharged.
The results will be discussed with you and your child at their next outpatient appointment.
Call the hospital if your child has:
What are the risks of the manometry study?
Please speak to your doctor if you have any questions or concerns about the study.
Developed by Departments of Gastroenterology and Paediatric Surgery at The Royal Children's Hospital, Melbourne. We acknowledge the input of RCH consumers and carers.
Reviewed December 2020.
Kids Health Info is supported by The Royal Children’s Hospital Foundation. To donate, visit
This information is intended to support, not replace, discussion with your doctor or healthcare professionals. The authors of these consumer health information handouts have made a considerable effort to ensure the information is accurate, up to date and easy to understand. The Royal Children's Hospital Melbourne accepts no responsibility for any inaccuracies, information perceived as misleading, or the success of any treatment regimen detailed in these handouts. Information contained in the handouts is updated regularly and therefore you should always check you are referring to the most recent version of the handout. The onus is on you, the user, to ensure that you have downloaded the most up-to-date version of a consumer health information handout.