Anal fissure

Anal fissure is a longitudinal tear that appears in the most distal portion of the anal canal. Its most frequent location is the posterior midline (90-98%), another less common location is the anterior midline (12% of those that appear in women and 7% in men). It has an equal incidence in both sexes and is more frequent in the middle age of life. Most are of unknown origin. The most likely explanation is acute trauma to the anal canal during defecation (large hard stools) and rarely by the explosive expulsion of liquid feces. The fact that the posterior wall of both the subendothelial and sphincter spaces are less vascularized makes them more vulnerable to the location of fissures. The passage to chronicity is due to both sphincter hypertonia and ischemia.

The presence of multiple fissures or in places other than those mentioned forces us to rule out diseases such as ulcerative colitis, Crohn's disease, tuberculosis, syphilis, immunodeficiency syndrome ... (Keep in mind that more than half of fissures secondary to inflammatory bowel diseases occur in the posterior midline and are painful).