What diseases fall under the scope of anorectal medicine? Various diseases of the anus, rectum and colon fall under the scope of anorectal medicine. Common anal diseases include internal and external hemorrhoids, anal fissures, anal fistulas and prolapse; colon diseases include ulcerative colitis, colon polyps, colonic diverticulitis, colon tumors and rectal prolapse. In addition, such as anal eczema, anal pruritus, acral warts, various congenital anorectal malformations also belong to the category of anorectal diseases. What factors are related to the occurrence of anorectal diseases in the Department of Anorectal Medicine, Guang’anmen Hospital, Chinese Academy of Traditional Chinese Medicine, Li Guodong? The occurrence of anorectal diseases is caused by a variety of factors, which can be summarized into two categories: endogenous and exogenous factors. Internal factors: (1) anatomical factors: the anorectal department has a large number of special structures, such as anal fossa, anal glands, anal papillae, rectal flaps and special vascular structures, such as the lack of venous flaps in the rectal veins, the side branches of the portal vein system and the vena cava system anastomosing at the lower end of the rectum, and the vascular cushion tissue on the dentate line, which easily cause common anorectal diseases such as hemorrhoids and anal fistula. (2) Physiological factors: The colon and rectum are the main organs for transporting food residues and storing feces, and the residues of food decomposed and absorbed by the body often carry a lot of harmful substances, which can induce tumors when they stay in the colon and rectum for a long time. (3) Genetic factors: genetic gene defects can produce multiple colonic polyps, P-J syndrome and other hereditary anorectal diseases. (4) Abnormal embryonic development factors: the anorectum is the result of the fusion of endoderm and ectoderm in the human body during embryonic development. If the development process is abnormal, many congenital anorectal diseases can be produced in the anorectal region, such as congenital anorectal disorder, congenital rectovaginal (urethral) fistula, congenital megacolon, etc. External causes: (1) bad defecation habits: reading books and newspapers in the toilet, resulting in prolonged squatting and defecation time, which can easily cause stasis of blood in the anorectum and induce disease. Smoking in the toilet can buffer the brain’s defecation reflex, which is very likely to cause constipation. Excessive force during defecation, some people do not care whether the feeling of defecation is strong, blindly and constantly fierce efforts to earn, can only make the rectum anus and pelvic floor muscles increase unnecessary burden, leading to the occurrence and development of disease. (2) defecation abnormalities: diarrhea and constipation are important factors in the pathogenesis of anorectal disease, constipation is the biggest bane, prolonged retention of toxic substances in the rectum can not only induce rectal cancer, and the accumulation of feces, affecting blood circulation, forceful solution of dry fecal mass, will certainly make the anus under greater pressure to produce bruising, swelling, fissures and a series of pathological changes. Diarrhea is often a clinical manifestation of colon disease, and diarrhea can also increase the chances of local infection in the anus, producing diseases such as anal sinusitis, inflammatory external hemorrhoids and perianal abscesses. (3) Dietary factors: It is natural that dietary patterns or dietary varieties inevitably change in daily life. Such as the quality of food coarse and fine, change in the type of vegetables and the amount of increase or decrease, the amount of protein, fat, starch, fiber and other content, water intake, can affect the composition of feces in the rectum, causing anorectal disease. The incidence of anorectal diseases has increased significantly due to the long-term consumption of alcohol or spicy food, which can stimulate the mucous membrane of the digestive tract and cause vasodilation and colon dysfunction. The national survey data prove that the incidence rate of spicy food is 61.6% and the incidence rate of wine drinkers is 64.6%, which are significantly higher than the total incidence rate. (4) Chronic diseases: such as long-term malnutrition and weakness, causing the anal sphincter to relax and become weak. Long-term chronic bronchitis, emphysema, rising abdominal pressure and pelvic stasis caused by coughing. Chronic hepatitis, cirrhosis, diarrhea, colitis, etc. are all triggers for the occurrence of anal diseases. Therefore, reasonable and effective preventive measures should be selected by focusing on the whole party status of the patient in prevention. Why is anorectal disease a common and frequent disease? Anorectal disease is a general term that includes anal, rectal and colonic diseases, and is a common and frequent disease in daily life. There is a common saying among our people that “nine out of ten people have hemorrhoids”, which is enough to explain the problem. Anal diseases can affect both men and women, and can develop in adults and infants, and national census data show that the incidence of anorectal disease in adults is about 60-75%, with a higher incidence in rural adults than in urban adults. Although less life-threatening, the more serious cases often affect normal work and life, and even the less serious cases have to endure the pain of the disease from time to time. Some infants suffer from anorectal disease, which not only affects their development and growth, but also causes a great burden to their parents. Therefore, we should pay attention to the prevention and treatment of anal diseases. Where is the anus located? The anus is the opening at the end of the digestive tract that leads to the outside of the body and is located on the midline of the buttocks, between the center of the perineum and the tip of the coccyx. The anal canal is normally closed in a longitudinal anterior-posterior fissure and expands in a circular shape during defecation, with a diameter of about 2-3 cm. What is the anal canal made of? What is the clinical significance? The anal canal is located below the rectum and above the anal verge. One is called anatomical anal canal, which starts from the anal verge and ends at the dentate line and is about 2.5-3 cm long. The superficial layer of the anal canal is metastatic epithelium and is surrounded by part of the internal and external anal sphincter and the joint longitudinal muscle. The other type is called the surgical anal canal, which starts from the anal margin and ends at the level of the anorectal ring about 1.5 cm above the dentate line. Its length is about 4.2 cm, and its wall is surrounded by all the internal and external sphincters, the joint longitudinal muscle and the anal levator muscle, which is also called the sphincter anal canal. The difference between anatomical and surgical anal canals is whether the terminal rectum is included in the anal canal. Although the former division has its morphological basis, the clinical application is more limited; the latter is based on clinical needs and is considered as the main tissue structure for controlling normal defecation, which provides some convenience for clinical treatment, but the inclusion of the terminal rectum brings inconvenience to the classification of diseases.