This document discusses fistula in ano and anal fissure. It defines a fistula in ano as an abnormal track connecting two epithelial surfaces, most commonly caused by anorectal abscess. It describes the classification, symptoms, diagnosis and management of fistula in ano, including fistulotomy and setons for simple vs. complex fistulas. It also defines anal fissure as a tear distal to the dentate line, most commonly caused by hard stool or constipation. It notes the pathogenesis is a cycle of pain and spasm that impairs healing. It provides details on the location, symptoms and treatment of acute vs. chronic anal fissure.