By Dr Vikas Shah, Consultant Radiologist

In my previous article, I described what the pelvic floor is, what problems you may suffer from if your pelvic floor fails, and went through one of the main tests of the pelvic floor: a proctogram. This article focuses on some of the main findings in proctogram tests.

A rectocele (pronounced rek-tow-seal) is bulge of the front wall of the back passage (the rectum) into the back wall of the vagina. The typical symptoms that this causes are:

  • feeling of a lump or fullness in the back of the vagina
  • needing to press from inside the vagina to empty bowels
  • feeling of stool being trapped and needing to go to the toilet repeatedly

The reasons for doing a proctogram when a rectocele is suspected are:

  • to confirm there is a rectocele
  • see how small or big it is
  • look for other pelvic floor problems that may influence the choice of treatment, such as rectal prolapse, how far down the pelvic floor drops when straining and an enterocele (loops of small bowel dropping down low into the pelvis and pressing on the rectum)

This image is taken from the end of a proctogram test and shows a bulge at the front of the rectum (towards the left of the picture) which is the rectocele.

A rectal prolapse is suspected when people complain of a feeling of a lump coming out of the back passage (anus, and is the final stage of the process known as intussusception. The problem starts with the lining of the bowel becoming thicker and looser (rectal mucosal thickening) and starting to droop down. When the lining of the rectum droops into the anal canal (back passage), this is known as anal mucosal (or internal) intussusception. This by itself will not cause a feeling of a lump coming out but commonly makes people feel a fullness in their back passage even when they don't need to go to the toilet. Eventually, the whole thickness of the wall of the bowel droops down into the anal canal (recto-anal intussusception) and may end up drooping down all the way to the anal verge (the outside of the back passage, known as a full thickness external prolapse). Usually the prolapse will go back in by itself or with some gentle pressure but sometimes it can stay outside permanently. Note that the terms rectal prolapse and intussusception are used interchangeably and refer to the same process.

When someone describes symptoms of a prolapse, a proctogram test is done because sometimes it is difficult to see a prolapse in clinic. Not only can the proctogram test reveal the rectal prolapse but it can also show how small or big it is, and show other problems such as an enterocele or a rectocele. This video clip (from my YouTube channel  shows the development of an external prolapse and an enterocele in a proctogram:


Please note that there is some confusing terminology about this on the Internet and even amongst hospital specialists. Some sites describe a rectocele as a rectal prolapse; technically speaking this is not a rectal prolapse. A rectocele is a weakening of either the front wall of the rectum or the back wall of the vagina, and the effect is a forward bulge of the rectum into the vagina. A rectal prolapse, strictly speaking, is the same process as intussusception, which is the telescoping of bowel into the adjacent bowel. 

Arguably the most difficult (and controversial) diagnosis to make is anismus or anorectal dyssynergy. This disorder is defined by abnormal relaxation or failure of relaxation of one of the core pelvic floor muscles: puborectalis. This muscle forms a sling around the back of the lower part of the rectum, and is normally contracted (tense). When someone attempts to open their bowels, it should relax, and allow the angle between the rectum and anal canal to straighten. In anismus, there is either a failure of relaxation, or what is known as paradoxic contraction, i.e. the muscle tenses even more. This means that the angle between the rectum and anal canal doesn't straighten properly, and usually very little or none of the barium paste is expelled. 

It is important to try to distinguish anismus from the effects of anxiety caused by the test. If someone feels anxious and tense, they may not be able to fully relax the muscle and the appearances then (wrongly) suggest anismus. The ways that this can be avoided include a full explanation of the test, time taken to go through any queries or concerns, a cohesive team of radiographers and radiologists, and most of all, showing empathy for the patient. We ask people to try to do something in a hospital room that they have difficulty doing in the privacy of their own home - go to the toilet. Therefore, it is an important part of the radiologist and radiographer's jobs to put the patient at ease to ensure that a false diagnosis of anismus is not reached.

Dr Vikas Shah
Consultant Radiologist in Leicester, UK