Hemorrhoids are divided into internal hemorrhoids, external hemorrhoids and mixed hemorrhoids according to their locations: Internal hemorrhoids: the surface is covered by mucous membrane, located above the tooth line, formed by the internal venous plexus of hemorrhoids, commonly found in the left median, right anterior and right posterior 3, often with a history of blood in the stool and prolapse. The external hemorrhoids are covered by skin, located below the dentate line, formed by the external venous plexus, and commonly include thrombosed external hemorrhoids, connective tissue external hemorrhoids (skin prolapse), varicose external hemorrhoids and inflammatory external hemorrhoids. Mixed hemorrhoids: near the dentate line, covered by the skin mucosal junction tissue, formed by the veins that anastomose between the internal and external hemorrhoidal plexus and have the characteristics of both internal and external hemorrhoids. The four stages of hemorrhoids: Stage I, no pain, mainly to blood, discharge, itching; Stage II, blood in the stool, hemorrhoids prolapse with defecation, but can return by themselves; Stage III (also known as late), internal hemorrhoids prolapse outside the anal opening, or each defecation out of the anal opening, can not return by themselves, must be held back by hand. In stage IV, the internal hemorrhoid prolapses out of the anal opening and cannot be returned to the inside of the anus. This is the most serious condition of internal hemorrhoids. Internal hemorrhoids occur above the dentate line of the anal canal. Internal hemorrhoids are generally painless, with blood and prolapsed hemorrhoids as the main symptoms, and in severe cases, blood will be sprayed, and the prolapsed hemorrhoids cannot be retracted by themselves, as well as difficulty in passing stools, inability to wipe clean after passing stools, and feeling of swelling. The internal hemorrhoids can be divided into three stages according to the degree of lesions and clinical manifestations: Stage I internal hemorrhoids with blood during defecation, no prolapse, nodular elevation of the mucosa on the dentate line; Stage II internal hemorrhoids with blood during defecation, dripping or shooting blood, prolapsed hemorrhoid nucleus, which can be returned after defecation; Stage III internal hemorrhoids prolapse during defecation or when coughing, exertion, weight-bearing causes increased abdominal pressure, and need to be returned by hand. External hemorrhoid type Vascular swelling type: The mucous membrane on the surface of internal hemorrhoids is rough and soft, dark red or vermilion in color, and bleeds easily when touched, and bleeding is the main symptom of this type. Varicose veins: The surface of internal hemorrhoids is hard, shiny, dark red or blue, and the hemorrhoids are filled with varicose veins and hyperplastic connective tissue. Fibrotic type: The surface of internal hemorrhoid is hard and elastic, and the surface of hemorrhoid body is slightly white fibrous tissue hyperplasia, which is easy to prolapse and not easy to bleed. Thrombosed external hemorrhoids: The main onset characteristics are sudden onset, severe pain, swelling and discomfort, and occasionally systemic symptoms. The local examination reveals a bulging swelling next to the anus, a hard and slippery subcutaneous mass can be palpated, and tenderness is obvious. Inflammatory external hemorrhoids: often caused by skin injury and infection at the anal verge, mostly with anal pain, which is aggravated during defecation, blood in the stool, and a small amount of discharge from the anus. Local examination of the raised swelling next to the anus, red in color, obvious congestion, tenderness, sometimes accompanied by general discomfort and fever. Varicose vein type external hemorrhoid: the anal edge is raised into an oval shape, soft to touch, painless, dark purple lump can be seen when straining during stool, and the volume can be reduced after defecation or rest, which is caused by subcutaneous varicose vein, also caused by the development of late internal hemorrhoids. The swelling is usually uncomfortable, and it is aggravated by fecal discharge, and painful only when inflamed. Connective tissue type external hemorrhoids or superfluous external hemorrhoids: It is caused by the enlargement of the skin folds at the edge of the anus and the proliferation of connective tissue, forming many superfluous hemorrhoids of different sizes and shapes. The difference between internal hemorrhoids, external hemorrhoids, and mixed hemorrhoids Internal hemorrhoids occur above the dentate line of the anal canal, and are generally painless. According to the degree of internal hemorrhoids and clinical manifestations, there are three stages of internal hemorrhoids: stage I internal hemorrhoids with blood during defecation, no prolapse, nodular elevation of the mucosa on the dentate line; stage II internal hemorrhoids with blood during defecation, dripping or shooting blood, prolapsed hemorrhoid nucleus, which can be returned after defecation; stage III internal hemorrhoids prolapse during defecation or when coughing, exertion, weight-bearing causes increased abdominal pressure, and need to be returned by hand. Internal hemorrhoids occur above the dentate line of the anal canal. Internal hemorrhoids are generally painless, with blood and prolapsed hemorrhoids as the main symptoms, and in severe cases, blood will be spurted, and the prolapsed hemorrhoids cannot be returned by themselves, as well as difficulty in passing stool, unclean wipe after stool, and a feeling of swelling. There is no pain in general, but there is severe pain when there is a thrombosis that becomes embedded. External hemorrhoids are located below the dentate line and have pain and lumps as the main symptom, and there are skin flaps of different sizes and shapes around the anus. Depending on their pathological characteristics, they can be divided into four types: varicose veins, connective tissue, thrombotic and inflammatory. The inflammatory external hemorrhoids are the most common, mainly manifesting as raised skin folds at the anal verge, redness, edema, congestion, pressure pain, increased pain during defecation, and a small amount of discharge, some of which can be accompanied by general discomfort and fever. Mixed hemorrhoids have both internal and external hemorrhoids, and the main clinical symptoms are prolapse of rectal mucosa and skin, swelling, pain, and recurrent infection. The internal hemorrhoids that are prolapsed outside the anus are held by the sphincter muscle, and the venous return is blocked, while the arterial blood is still being input to make the hemorrhoid nucleus grow in size until the arterial blood vessels are pressed shut and the thrombus forms, resulting in a hardened, painful nucleus that cannot be returned to the anus, called an embedded hemorrhoid. The embedded hemorrhoid can become infected to varying degrees. If the infection is not treated properly, it can easily spread and cause abscesses in the submucosa, perianal or sciatic rectal fossa. If the dislodged bacterial emboli travel up the vein, and if antibiotics are not used properly or any antibacterial drugs are not used, portal vein bacteremia or even sepsis can form, and liver abscesses can also form. The most important point in treating an embedded hemorrhoid is to promptly return the prolapsed hemorrhoid and release the embedded mass.