1. Diagnosis 1. Symptoms (1) Pain: Characterized by pain directly related to defecation, which can be radiated to the sacrococcygeal region, especially when the stool is dry. The pain often lasts for a long time after defecation, often ranging from several minutes to several hours, and even the pain cannot be relieved for a day, and is relieved only before the next defecation. (2) Bleeding: The bleeding is sporadic and usually not much, but it may appear as blood on hand paper or blood dripping after stool, and the color of bleeding is bright red. (3) Itching: It is caused by the secretion from the fissure ulcer or the secretion from the anal sinusitis and anal papillitis that are complicated by the fissure. (4) Constipation: Constipation is one of the causes of anal fissure, which in turn can cause constipation. Because of the severe pain in the anus during defecation, patients often have the fear of defecation, thus artificially controlling defecation, resulting in prolonged retention of stool in the rectum and more dryness due to excessive water absorption, making defecation more difficult, thus forming a vicious circle. The patient should be in a suitable position and the inspector should use both thumbs to gently separate the skin of the anal verge to both sides. A poke-shaped ulcer can be seen in the skin of the anal canal migration area, and if the ulcer surface is lightly touched with a probe, it can cause obvious pain. The ulcer surface of old anal fissures is grayish white, with a deep base and obvious thickening of the edges, and a fissured hemorrhoid can be formed at the lower end, which together with the enlarged anal papilla at the upper end of the ulcer is called the anal fissure triad. (1) Early anal fissure (fresh anal fissure) has a poke-shaped ulcer in the epithelium of the anal canal, with shallow trauma, neat and elastic edges, fresh or gray base, no obvious scarring, and easy healing. (2) Old anal fissure Because the sphincter often remains contracted, the ulcer surface is combined with infection, and the wound surface is poorly drained, resulting in hardening and thickening of the ulcer margin, inflammation, congestion, edema, fibrosis, obstruction of venous and lymphatic flow, causing edema and connective tissue hyperplasia. It is often combined with pathological changes such as anal papillomegaly, superfluous external hemorrhoids (sentinel hemorrhoids) and subcutaneous fistula. The treatment of anal fissure includes non-surgical and surgical treatment. Non-surgical treatment is generally available except for old anal fissures that do not heal for a long time. The principles of treatment are: to eliminate the symptoms of anal fissure and to promote the healing of fissure.