Rectum and anal canal junction line for the dentate line, the dentate line is located in the upper edge of the anal canal distance from the anal verge of about 1.5 to 2 centimeters, so the normal rectal mucosa is palpable. Rectal mucosa of the lowermost distance from the anal verge of about 2 centimeters, under normal circumstances can be touched to the texture of the softer and smoother state. If the touch is accompanied by tenderness, lumps, strictures, bleeding, etc., further examination is needed to clarify the cause. Usually the doctor takes the left side lying position, chest and knee position, amputation position to the patient for rectal fingerprinting, it is recommended not to touch the rectum self-diagnosis, to avoid pain, leakage of diagnosis. Touching the rectum is of great significance for early detection of anal canal, rectal cancer and other diseases, and it is necessary for professional doctors to standardize the operation of diagnosis and treatment in order to avoid self-diagnosis and treatment causing delays in the condition.