It is well known that the anal area is rich in nerves and has a keen sense of sensation, and any stimulation can lead to anal pain. The pain can be manifested as stinging, distension, burning, crushing pain, etc. Its pain can occur during defecation, after defecation, or not related to defecation. So how do you differentiate and diagnose the two symptoms of distension and discomfort in the rectum and anus and sharp anal pain? Severe anal pain As the name suggests, there is severe pain in the anus. It usually occurs during a bowel movement, but can also occur during non-bowel movements. It is mainly associated with the following diseases: perianal abscess, embedded hemorrhoids, anal fissure, advanced anorectal cancer, and foreign bodies in the anus. Diagnosis needs to be based on specific circumstances, the following anal fissure as an example: anal fissure symptoms have clear characteristics, as long as the detailed interrogation of the history of the course of the disease, as well as pain, bleeding characteristics, diagnosis is not difficult. However, in order to improve the accuracy of diagnosis and prevent mistakes, the diagnosis should be strictly based on several aspects of questioning, palpation, visual diagnosis and biopsy to differentiate the diagnosis. Visual diagnosis: acute anal fissure anus can be seen in the secretion, pull open the buttocks can be seen in the lower end of the anal fissure, such as using a probe to gently touch the lower end of the fissure, can cause pain; chronic anal fissure is common with connective tissue external hemorrhoids. Diagnosis: because of sphincter spasm anal tightening, such as excessive force, often cause severe pain, sometimes have to check under local anesthesia. Fissure felt in the anus, acute soft edge, shallow bottom, elastic, sensitive to touch; chronic side of the hard protrusion, the bottom of the deep, inelastic. Speculum examination: visible ovoid ulcers, or see small fissures. Acute anal fissure fissure edge neat, bottom light red; chronic anal fissure fissure edge is not neat, bottom deep gray-white, some serious anal fissure can also be seen sphincter fibers. Differential diagnosis: must be differentiated from tuberculous ulcers, syphilitic ulcers, soft chancre and epithelial cancer ulcers. Ulcerative colitis and granulomatous colitis complicated by anal fissure are very easy to distinguish. Rectal distension and discomfort: Rectal distension and discomfort is the most common symptom of anorectal diseases, due to the relationship between anatomy and physiology, the pain of anorectal diseases mostly occurs in the lower abdomen, perineum, anal verge and lower rectum. Differential diagnosis: 1, rectal and anal stenosis: it refers to the luminal diameter of the anus, anal canal and rectum become thin, deformation or different degrees of intestinal obstruction, called anal and rectal stenosis. Because of the different parts of the stenosis, anal stenosis and rectal stenosis (mostly seen above the dentate line 2.5-5cm or rectal jugular abdominal), stenosis is often within 10cm, and the nature of the primary lesion, stenosis of the upper end of the dilatation, the stenosis of the secondary vesiculobullous. ulceration, formation of epileptic scars or replacement by other tissue. The general diagnosis of this disease can provide important information, but the upper end of the lesion is more hidden, and should be done to do multiple examinations in order to make a correct diagnosis. 2, anorectal malformation: is the more common digestive tract malformation, its variety of complex pathology, not only the anorectal itself developmental defects, the muscles around the anus – puborectalis muscle, the external anal sphincter and internal sphincter have different degrees of change, neurological changes are also one of the important changes of this malformation, in addition to the malformation associated with the high incidence of malformations of other organs, some of the cases are multiple malformations. In addition, there is a high incidence of malformations of other organs associated with this malformation, and some cases are multiple malformations or malformations that seriously jeopardize the life of the child.