Anorectal Physiology & Ultrasound

An anorectal physiology test assesses the strength of your pelvis muscles, sphincter and nerves, while the ultrasound examines the structure of your pelvic floor muscles and any damage they might have had.

Anorectal refers to the anal canal and rectum, which are the parts of the bowel just inside your bottom.

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On this page, we’ll answer the following questions:


Why do I need an anorectal physiology test?

Anorectal physiology tests are the basic way to investigate your pelvic floor structure and function.

At Brisbane Colorectal, we request these tests for many patients with incontinence, obstructed defaecation syndrome and prolapse. We also perform them in patients with other conditions affecting the bottom, such as anal fistulas and fissures. These tests may be combined with a special X-ray and transit studies.

How do I prepare for an anorectal physiology test?

You don’t need to do anything to prepare – although it’s advisable to try to empty your bladder beforehand.

Since the tests don’t require any sedation, you can drive yourself to and from the appointment.

What happens during an anorectal physiology test?

Before the procedure, you’ll be asked to complete some questions about your symptoms while you wait. Then your doctor will take the time to explain the procedure to you.

You’ll also be given two small enemas. This is a painless procedure where liquid is put directly into the rectum, washing out the lower part of the bowel.

The tests are performed by a doctor and a nurse in a private room, and take around one hour.

Anorectal manometry

You’ll be asked to remove the clothing on your lower half, and lie on your left side with your knees bent. Your doctor will examine your bottom and perform a “PR examination” by inserting a gloved finger.

A small probe, around the size of a pen, will then be inserted. Your sphincter muscle strength will be tested by asking you to rest, squeeze and bear down. A small balloon attached to the probe will be inflated to test how it feels for you, as sensation can be abnormal in many patients with pelvic floor problems.

What can be learnt from anorectal manometry?

Normally, when stool enters the rectum, the anal sphincter muscle tightens to prevent the stool exiting the body at an inconvenient time. If this muscle is weak or doesn’t contract in a timely way, incontinence (stool leakage) can occur.

When a person pushes to have a bowel movement, the anal sphincter muscles are supposed to relax. This causes the pressures in the rectum to decrease, allowing the evacuation of stool. If these muscles tighten when pushing, this could contribute to constipation.

Anal manometry measures how strong the sphincter muscles are, and whether they relax as they should when passing a stool. It provides helpful information to the doctor in treating patients with faecal incontinence or severe constipation.

Faecal incontinence has many causes, including weak anal sphincter muscles or poor sensation in the rectum. These problems can be treated with biofeedback techniques using anal manometry and special pelvic floor exercises.

Similarly, there are multiple causes of constipation. Some involve sluggish movement through the whole colon, whereas others involve the anal sphincter muscles. In some patients with constipation, the anal sphincter muscles do not relax properly when pushing to have a bowel movement. This causes a type of obstruction. The good news is muscles that don’t relax with bearing down can be retrained with biofeedback techniques using anal manometry.


An ultrasound test will follow anorectal manometry. This involves inserting a different probe, about the thickness of a finger, into the bottom. You’ll then be asked to stay still and relax for the rest of the procedure.

As well as the above tests, electromyography (EMG) and pudendal nerve testing may be performed.

Pudendal nerve testing

This procedure evaluates the nerve supply to the anal muscle. A flexible circuit is attached to the doctor’s gloved finger and inserted into the bottom. The circuit contains a stimulating electrode and a recording electrode. This means the device stimulates the nerve and records the response at the same time.

You simply lie still and relax during this procedure. You may feel a slight pulse from the finger electrode, but this is very tolerable and causes no pain.

Anal sphincter EMG

Anal sphincter electromyography (EMG) examines the muscle contractions during squeezing, and muscle relaxation during pushing. It involves the placement of two small electrodes on either side of the anus. You’ll be asked to relax, squeeze and push at different times and the anal sphincter muscle electrical activity will be recorded.

What happens after an anorectal physiology test?

Once the testing is finished, you’ll be able to drive or take public transport, and go about your normal activities.

A report will be created based on your questionnaire answers and the outcomes from your procedure. An outpatient appointment will be booked for you to discuss results and treatment options. If you were referred for these tests by another doctor, your results will be sent to them.

Are there any risks with anorectal physiology tests?

Anorectal physiology tests are safe, low risk procedures that are unlikely to cause any pain.

Please let your doctor or nurse know if you do experience any pain or discomfort, or if you wish to pause during the tests.

Be assured that complications from anorectal physiology tests are rare. However, there is a possibility that the rectum could tear or bleed. Another remote possibility is equipment failure.

If you’re allergic to latex, do let us know when you arrive for your appointment. Your doctor can then make the easy switch to latex-free PPE.

How much do anorectal physiology tests cost?

The cost for the tests and a consultation with Dr Gillespie is $400. This is payable at your appointment.

You’ll receive a rebate from Medicare of $75.15, unless you have reached your Medicare Safety Net. Unfortunately you will not be able to claim a rebate from your private health insurer.

Can’t find what you’re looking for?

If you’ve been advised or suspect that you have a condition and it’s not listed here, please, call us on 07 3010 3360 and speak to our friendly team to see how we can help.