This is a cut in the lining of the anal canal at the level of the opening of the anus and just inside the anal canal. This may be superficial or deep depending on the chronicity of the condition.

Superficial fissures are usually fresh cuts, quite painful, seen after a bout of the forceful strained expulsion of a hard stool and associated with fresh bleeding.

Chronic fissures are usually deep. They are associated with chronic episodes of constipation. They are usually seen in the midline either posteriorly or anteriorly. They have thickened edges and maybe muscle deep, adherent to the underlying internal sphincter. They are associated with skin protrusions called sentinel skin tags.

Fissures cause the patient severe pain and bleeding during defecation, especially if constipated. They are associated with fresh bleeding which streaks the stools. In chronic deep fissures, the pain might persist for many hours after the act of defecation is completed. The patient experiences difficulty in sitting as well as in walking.

Initially, conservative treatment may be attempted. This includes high fiber diet, plenty of oral fluids, laxatives and local application of creams to alleviate pain and initiate healing of the fissure. The patient must be counseled about healthy food habits. Adequate fruits, vegetables giving fiber and plenty of oral fluids are a prerequisite in the diet for a comfortable stool.

When conservative treatment fails, one has to think in terms of the surgery called excision of the fissure with lateral sphincterotomy or anal dilatation. These surgeries help to freshen the edges of a fissure so that it now can heal and to loosen the spasm of the anal canal to help passage of stool to become smooth and pain-free.

An untreated, longstanding fissure besides being uncomfortable, may trouble a patient further by giving rise to complications such as abscesses and fistulae.