Anal Stenosis

What is anal stenosis?

When a tubular organ or blood vessel becomes excessively narrow such that it can no longer perform as nature intended, it is a condition referred to by physicians as stenosis. Anal stenosis, also known as an anal stricture, is the narrowing of the anal canal, located just before the anal sphincter.

What is the anal sphincter?

The anal sphincter is a complex part of the body that maintains a seal that can be opened to discharge body waste. It is strong enough to restrict the passage of any fecal material but sensitive enough to differentiate between solid, liquid, and gas. There are actually two anal sphincter muscles … internal and external.

Illustration showing the external and internal sphincters of the rectum labelled: Rectum, Exterior sphincter, Interior SphincterThe internal anal sphincter is a thin, white muscle wrapped around the anal canal. The internal sphincter contracts during rest and sleep, and keeps small amounts of liquid and gas from escaping unexpectedly. The internal anal sphincter is an involuntary smooth muscle, like the muscles of your intestines. You cannot mentally control it.

The external anal sphincter is a thick, red voluntary muscle. It is wrapped around the internal anal sphincter muscle. It is the one you squeeze when you feel the urge to go to the bathroom but are not near one. Since it is voluntary muscle, like the muscles in your arms and legs, you can control it.

When food waste reaches the anus, it begins collecting in the flexible rectum. When enough waste has collected, a person will feel the need to go to the bathroom. Once the person is seated on the toilet, the anal sphincter should relax and allow the anal canal to empty. When the waste has been released from the canal, the anal sphincter should restrict and remain in that condition until the process needs to occur again.

But there can be problems … and one of those problems is called anal stenosis. Anal stenosis is a serious condition that can greatly impact a person's lifestyle and total well-being.

What causes anal stenosis?

Anal stenosis can be the result of many things, such as:

  • complications resulting from a surgical procedure
  • overuse of laxatives
  • a severe blood infection (sepsis) that compromises organs in the body
  • loss of blood to a particular area of the body
  • AIDS and venereal diseases
  • an infection caused by the amoeba entamoeba histolytica
  • inflammatory bowel disease (IBD), a disorder or inflammation of the colon and small intestine

There is a condition known as Anal Crohn's disease that mimics the symptoms of anal stenosis. Crohn's disease is an inflammation that can restrict the anal canal.


Symptoms can vary depending on the severity of the stenosis. They may include:

  • constipation
  • painful bowel movements
  • stools that are difficult to expel, are narrow, and break apart like pellets
  • evidence of bright red blood in the toilet (rectal bleeding)

Treatment of anal stenosis

Fortunately, preventing the condition from even occurring is the best treatment. But that is not always an option, especially if you must undergo surger

Some common preventative measures are:

  • fiber supplements; more fiber in your diet naturally softens stools, allowing them to pass more easily
  • stool softeners or emollient laxatives, which add moisture to the stool
  • sphincterotomy, a procedure in which the anal sphincter muscle is cut to open the anal canal

Surgical procedures to alleviate anal stenosis

The procedure that is performed to relieve anal stenosis is called an anoplasty. There are many variations of this procedure, and one is selected depending on the size and structure of the stenosis.

After surgery

  • Do not lift anything over 20 lbs. for ten days.
  • Shower only, no baths.
  • Avoid sitting directly on the surgical area.
  • Resume regular diet.
  • Drink eight 8 oz. glasses of water per day.
  • Resume previous medications, but patient should check with his/her doctor before taking any blood thinners or aspirin.

Things to remember

  • Anal stenosis can be disabling to the person who suffers from it.
  • People sometimes resort to excessive use of laxatives to find temporary relief.
  • Anal stenosis can be a disabling condition, affecting quality of life in many ways.
  • Depending on the severity of the condition, surgery may be an option.