Anal fissures are an extremely common condition in proctology. They occur in the fragile and narrowest tissue of the anal canal due to the combined effect of various internal and external factors, leading to the opening and cracking of the digestive tract outlet up to the dentate line and the surface of the anal margin. The oval-shaped small ulcers that form from anal fissures usually occur at the anal region, aligning parallel to the longitudinal direction of the anal canal. The condition is often recurrent and difficult to heal. The angle continuation between the anal canal and the rectum means that the posterior wall of the anal canal is under the most pressure during bowel movements. Therefore, the posterior midline is most susceptible to injury and is also the most common site for the occurrence of anal fissures.