Last reviewed 09/2020
An anal fissure is a crack in the wall of the anal mucosa so that the circular muscle layer is exposed. The tear usually occurs directly posteriorly and in the midline.
Men and women are equally affected. The peak incidence is in the 20-30 year old age group.
An anal fissure may be produced secondary to inflammatory bowel disease, especially Crohn's, in which case it should heal with successful medical treatment of the primary condition.