Hemorrhoids are the most common benign anal disease. Pathological changes or displacement of the supporting structures of the anal cushion, the venous plexus and the anastomosing branches of the arteries are internal hemorrhoids; pathological dilatation or thrombosis of the subcutaneous venous plexus distal to the dentate line are external hemorrhoids; internal hemorrhoids fuse with each other through the rich anastomosing branches of the venous plexus and the corresponding parts of the external hemorrhoids as mixed hemorrhoids. The internal hemorrhoids are not the terminal branches of the superior rectal veins, but the hypertrophied and displaced anal cushions. Internal hemorrhoids are located above the dentate line and covered by rectal mucosa on the surface. The degree of hemorrhoid prolapse is divided into four degrees: first degree, only bleeding in defecation, hemorrhoids do not prolapse outside the anus; second degree, hemorrhoids prolapse outside the anus during defecation, and then return on their own after defecation; third degree, hemorrhoids prolapse outside the anus and require hand assistance to return; fourth degree, hemorrhoids remain outside the anus for a long time and cannot be returned or are returned and then immediately prolapse. 2.External hemorrhoids are located below the dentate line and covered by the skin of the anal canal. They are divided into connective tissue external hemorrhoids (dermatomes), varicose veins external hemorrhoids and thrombosed external hemorrhoids. 3.Mixed hemorrhoids are formed by the fusion of internal hemorrhoids and external hemorrhoids through the anastomosing branches of rich venous plexus, which are located above and below the dentate line and covered by rectal mucosa and anal skin on the surface. When internal hemorrhoids develop to the second degree or higher, they often form mixed hemorrhoids. When mixed hemorrhoids develop gradually, the surrounding tissues are destroyed and atrophy occurs, and the hypertrophic anal cushion gradually increases in size, moves down, and prolapses outside the anus. When the prolapsed hemorrhoid is in the shape of a plum blossom around the anus, it is called a “ring hemorrhoid”. If the prolapsed hemorrhoid is embedded by the spastic sphincter to the point of edema, bruising or even necrosis, it is clinically known as an embedded hemorrhoid or strangulated hemorrhoid.