Anal Fissure (Fissure in Ano; Anal Ulcer) By Parswa Ansari, MD, Hofstra Northwell-Lenox Hill Hospital, New York Reviewed / Revised Jan 2023 View Patient Education Symptoms and Signs Diagnosis Treatment More Information Topic Resources Anal Fissure An anal fissure is an acute longitudinal tear or a chronic ovoid ulcer in the squamous epithelium of the anal canal.