An anal fissure is a small cut in the skin of the anus. The anus is the opening through which bowel movements pass.
Anal fissures are a fairly common disorder and occur more often in women.
Anal fissures are usually caused by small tears in the skin of the anus. These tears occur during bowel movements when hard, dry stools are passed. Although the doctor can usually diagnose an anal fissure by physical exam, a procedure called anoscopy may be used to confirm the diagnosis. This procedure uses an instrument called an anoscope to examine the anus and lower part of the rectum. Your doctor may want to perform additional studies, such as a sigmoidoscopy, if there is any question about the cause of the fissure.