Anal narrowing

Patients who suffer from constipation sometime feel that is because their anal opening (anal canal) is too narrow.  In fact, this is rarely ever the case.  In most instances, constipation has less to do with the anal canal itself and more to do with the function of the muscles in the bowel wall and surrounding the rectum.

True anal narrowing (stenosis) is quite rare and is almost always a compliation of surgery.  In fact, anal stenosis is one of the two dreaded complications of anal surgery, the other being damage to the sphincter (control) muscles.  Stenosis after surgery is usually the result of removing too much tissue.  So, at surgery, a careful surgeon will keep this in mind and make sure to leave adequate normal tissue in order to avoid a stenosis.  When a true stenosis does happen, it can be very difficult to fix.

Some patients may develop a stenosis from a chronic fissure, without ever having had surgery.  This can happen if the fissure is deep and has been present for years, leading to infection, scarring and contraction of the underlying muscle. However, most patients who seem to have a narrow anus when they have a fissure really just have a normal anal canal caliber, but it is made to seem narrow due to the intense muscle contraction that a fissure can cause.

© Pezim Clinic, Vancouver, British Columbia, Canada