anal fissure

Anal fissure is a small ulcer of the full thickness of the anal canal skin below the dentate line, oriented parallel to the longitudinal axis of the anal canal, approximately 0.5-1.1 cm in length. Initially, there is only a small tear in the anal canal skin, which may sometimes extend to the subcutaneous tissue or even to the superficial layer of the sphincter. The tear is linear or fusiform in shape; when the anus is opened, the wound surface becomes round or oval and is difficult to heal. Superficial lacerations of the anal canal should not be considered anal fissures, as they heal quickly and are usually asymptomatic. Anal fissures commonly occur in the posterior and anterior midline of the anus, predominantly in the posterior part, and are less common on the lateral sides. If an anal fissure occurs laterally or there are multiple fissures, it may be an early manifestation of inflammatory bowel disease. Anal fissure is a common anal canal disease, predominantly affecting young adults, can also occur in children, and is less common in the elderly. Some data show that in China, it is more common in males than females, but clinical observation indicates that more females than males seek medical attention.