a break in the skin lining the anal canal, usually causing pain during bowel movements and sometimes bleeding. Anal fissures occur as a consequence of constipation or sometimes of diarrhoea. Treatment is by soothing ointments, but if the condition is severe the operation of lateral sphincterotomy (cutting the muscle of the anal sphincter) is required.
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fissure in ano a painful linear ulcer at the margin of the anus.Medical dictionary. 2011.