In order to understand these two diseases more deeply, it is necessary to understand several anatomical structures of the anorectum 1, rectal column: rectal column or anal column, the mucosal folds of the wall of the intestinal cavity, there are 6-14, about 1-2 cm long, rectal column is the result of the contraction of the anal sphincter, when the rectum dilates this column can disappear, each column of the submucosa are independent arterial veins and muscle tissue, the more down the rectal column, the more significant. especially in the left wall. Right posterior. The right anterior wall is the most obvious, and primary internal hemorrhoids often occur in the above three places when varicose veins are present in the column. 2.Anal flap: The lower end of each rectal column is connected by half-moon shaped mucosal folds, these half-moon shaped mucosal folds are called anal flaps. 3, anal fossa: anal fossa, also known as anal sinus, is a small diverticulum located between the anal column after the anal flap, its number. Depth and shape vary greatly. The human anal fossa has 6-8, funnel-shaped, the upper mouth toward the upper part of the intestinal cavity, the bottom of the fossa toward the bottom, the depth is generally 0.3-0.5cm more constant and large anal fossa is usually in the posterior wall of the anal canal. Because the place is often easy to accumulate fecal impurities, prone to infection, causing anal cryptitis. 4, anal papillae: generally the anal canal and rectal column connection area raised small cone or triangular small bump called anal papillae, anal papillae surface covered with smooth creamy white or light red skin, along the anal dentition line most people do not have anal papillae, with anal papillae accounted for 13%-47%, often combined with anal cryptitis papillae more than 2-6, the number of morphological size varies from person to person, when there is infection at the anal canal. When the anal canal is infected, injured or chronically irritated, such as anal fissure, the anal papillae may become enlarged and prolapse out of the anus, forming anal papillitis or anal papillomegaly. Some of them may be papillomas, which are often fibrous polyps and are usually not malignant, and can be eradicated by electrocautery, ligation or surgical excision. They can be cured by electrocautery, ligation or surgical excision. The anal sinus is poorly drained because the bottom of the sinus is underneath and the opening is upward, so it is easy to store feces and cause infection and injury, and the edge of the sinus has a half-moon anal flap, so it is also easy to be bruised by dry feces or torn during defecation. Increased number of bowel movements or enteritis. Dysentery. Diarrhea. Frequent irritation of the anal sinus and flap due to constipation, etc. Decreased body and local resistance, or chronic wasting diseases, feces and foreign bodies accumulate in the anal sinus, the sinus tract is blocked, so that the drainage is not smooth, coupled with the decomposition of feces, germs multiply, the anal sinus is inflamed and swollen, the common causative agent is Escherichia coli. Anal papillitis, also known as anal papillomegaly, is an inflammatory proliferative lesion of chronic fibrosis of the anal papillae, which is often complicated by sinusitis and is a common complication of anal fissures and fistulas, and severe fibrosis of the anal papillae, also known as anal papillary fibroma.