Cramp-like pain in the small abdomen and anus is considered to be spasmodic pain, both of which are caused by an acute attack of anal fissure. Due to dry, rough stool, the anal fissure is caused by cutting directly through the anus during defecation, which then causes cramp-like pain in the small abdomen and anal area, and local pain caused by contraction of the pelvic muscles around the anus due to an acute attack of anal fissure. Due to constipation, the tension around the anus is greater during defecation, the front and back of the anus is more pronounced, and defecation is dry and strenuous, leading to fissures in the skin, mucous membrane and soft tissues of the anal area. After defecation, patients with anal fissures will show pain or bleeding due to localized fissures. Repeated attacks will form old anal fissures, when the fissures are deeper and not only the skin and soft tissues are damaged, but also the deeper muscles are fractured, resulting in persistent painful attacks, and most patients need surgery to relieve them.