TY - CHAP M1 - Book, Section TI - Anal Fissure A1 - Dooley-Hash, Suzanne A1 - Herrman, Nicholas W.C. A2 - Knoop, Kevin J. A2 - Stack, Lawrence B. A2 - Storrow, Alan B. A2 - Thurman, R. Jason Y1 - 2021 N1 - T2 - The Atlas of Emergency Medicine, 5e AB - An anal fissure is a longitudinal tear of the skin of the anal canal that extends from the dentate line to the anal verge. It is the most common cause of painful rectal bleeding. Fissures are thought to be caused by the passage of hard or large stools with constipation, but may also be seen with diarrhea. Incidence follows a bimodal distribution with fissures most commonly seen in infants and middle-aged adults. Patients present with intense sharp, burning pain during and after bowel movements. Pain may be accompanied by bright red blood. Gentle examination with separation of the buttocks usually provides adequate visualization. Anal fissures are typically a few millimeters wide and most commonly occur in the posterior midline where the skeletal muscle fibers encircling the anus are weakest. SN - PB - McGraw-Hill CY - New York, NY Y2 - 2024/03/28 UR - accessmedicine.mhmedical.com/content.aspx?aid=1181041452 ER -