A, anorectal anatomy: rectum: upper sigmoid colon, lower connected to the anal canal, the total length of 12-15 cm, rectal bladder trap, women for the rectum uterine trap. Rectal column: the lower end of the rectum is connected to the anal canal, about 10. Anal valve: a half-moon shaped wrinkled pocket between adjacent rectal columns. Anal sinus (anal saphenous fossa): between the anal valve and the wall of the rectum, opening upward funnel-shaped gap. Dentate line: the base of the anal valve and the rectal column, forming an untidy jagged edge at the junction of the rectum and anal canal. Comparison of the upper and lower anatomy of the dentate line. Second, anorectal examination methods: 1, position: knee-chest position: this position so that the anal canal is sagging, the anal part of the exposure is clear, to the viscera upward, the pelvis is empty, the inspection is convenient and easy to succeed, for the most commonly used position. Left prone position: this position is suitable for the weak or simple treatment at the same time. Cut stone position: exposure is clear, can be done at the same time for double diagnosis, this position is also a common position for rectal-anal surgery. Squatting position: suitable for the examination of internal hemorrhoids, prolapse or rectal polyps, etc., this position of rectal-anal tube pressure is the largest, visible internal hemorrhoids and prolapse of the most serious situation. Bending over to hold the chair position: poor exposure, but convenient and time-saving, suitable for crowd health census. 2, visual diagnosis: whether there is blood, pus, feces, mucus, fistula, lumps, eczema, ulcers, scarring, anal constriction or laxity, external hemorrhoids, prolapsed internal hemorrhoids or rectal mucosa, pinworms, fissures, sentinel hemorrhoids, let the patient to the anus to force the direction of the anus, to observe whether there are internal hemorrhoids, polyps or prolapse of anorectal and so on. 3, rectal diagnosis: simple but important. 4, anoscopy: first all into the anus, and then slowly exit, observation, according to the clock record, comprehensive observation, do not miss. Contraindications: anal stenosis, women’s menstrual period, anal fissure or local inflammation pain is obvious. 5, sigmoidoscopy: is the diagnosis of the upper rectum and the lower sigmoid colon lesions of the important examination methods, on: unknown blood in the stool, mucus stool, chronic diarrhea, acute and severe, fecal thinning and other clinical manifestations, should be considered sigmoidoscopy. Methods: One day before the examination, give a non-detergent diet and laxatives, and give an enema before the operation. The first anal finger-pointing, into the mirror about 15 centimeters, the intestinal lumen becomes smaller and has spiral mucosal folds, that is, the sigmoid colon. Biopsy can be taken at the same time, but do not take the center of the ulcer or the ulcerated part of the tumor to avoid perforation. Complications: bleeding, perforation. 6, X-ray barium enema examination: filling defect or mucosal destruction. 7, Fecal examination: suitable for long-term constipation, determination of anal sphincter and anorectal morphology, function and dynamics of the method. 8, CT examination: to understand the location and size of the tumor, to provide the relationship between the tumor and the surrounding pelvic organs and the scope of tumor invasion, and to carry out the staging of rectal cancer. 9.MRI: preoperative rectal examination or postoperative review. 10. Rectal cavity ultrasound scanning: preoperative staging and postoperative review of rectal cancer. Hemorrhoid Definition: soft venous mass formed by varicose veins at the lower end of rectum and anal verge, mostly seen in 20-40 years old. (A) etiology: 1, anatomical factors: rectum and anal canal is located in the lower part of the trunk, portal venous system without venous flap, hemorrhoids within the venous plexus increased pressure. 2, increased intra-abdominal pressure: pregnancy, urinary difficulties, constipation and so on. 3.Chronic infection of the lower rectum and anal canal. 4, Congenital defects or trauma. (B) clinical manifestations: internal hemorrhoids, external hemorrhoids, mixed hemorrhoids. 1.Bleeding: not mixed with feces, or dripping blood during defecation. 2.Projectile: mostly ring row. 3, pain: infection, erosion, thrombosis or incarceration when the pain is obvious. 4.Itching: combined with eczema. Internal hemorrhoids: varicose vein plexus on rectum. Stage I: bleeding during defecation, no pain, no prolapse, occurring in the left, right anterior and right posterior anal canal. Stage II: prolapse during defecation, can be self-returned, blood in stool is obvious. Stage III: prolapse during defecation, coughing, straining, walking, squatting, can’t be self-returned, must be hand-held back, easy to be embedded and necrotic. Stage IV: internal hemorrhoids continue to prolapse, can not be returned, hemorrhoid surface covered with skin, mostly in the elderly. External hemorrhoids: located below the dentate line, formed by the varicose vein plexus under the hemorrhoids, the surface covered with skin, can not be pushed into the rectum. Easy to form thrombosed external hemorrhoids, there are external hemorrhoids skin.