How do hemorrhoids occur? Hemorrhoids themselves are clusters of veins created by varicose veins due to stasis. The pressure in the veins around the anus rises during defecation, which in turn causes the blood vessels to bulge out like balloons, forming a venous aneurysm-like hemorrhoidal core. Hemorrhoids can occur for a number of reasons, the most important of which is thought to be the rise in blood pressure during defecation. When defecation force leads to increased abdominal pressure, compression of the veins of the anus, so that the pressure of the vein wall surge, that is, the pressure within the veins to increase, so for years and years and years of repeated prolonged force defecation so that the fragile walls of the blood vessels in the pressure of the expansion of, tortuous, into a group, like the poor quality of the balloon as the formation of tumors, the blood vessels of such a group is the hemorrhoids nucleus. Classification of hemorrhoids Hemorrhoids occurring above the dentate line are internal hemorrhoids, and hemorrhoids occurring below the dentate line are external hemorrhoids. Hemorrhoids are classified as internal or external depending on where they occur. There is a jagged line between the anus and the rectum called the dentate line. External hemorrhoids occur below this line, and internal hemorrhoids occur on the rectal side above this line. Bounded by the dentate line of the anus, above it is the mucous membrane of the digestive tract, which has no nerves for pain; below it is the skin, which is rich in nerve endings. Therefore, internal hemorrhoids are painless and external hemorrhoids are painful and intense. Above the dentate line is the rectum, which is a continuation of the mucous membrane of the alimentary canal, and the stomach, intestines, as pain is slow, so the internal hemorrhoids are almost painless. The corresponding internal hemorrhoids are covered with a soft mucous membrane, so the mucous membrane tends to rupture and bleed when dry, hard feces passes through. In contrast, external hemorrhoids occur below the dentate line, close to the buttock side, and this area is part of the skin, so there are somatic nerves passing through this area as well as the skin, which are sensitive to stimuli. When the nucleus of external hemorrhoids is soft, there is usually less pain, but when a blood clot is formed in it, i.e., when thrombosed external hemorrhoids are formed, the pain begins to be severe, and because the surface of external hemorrhoids is covered with firm skin, not mucous membranes, there is little or no bleeding. Most external hemorrhoids are single and located on the left and right sides of the anus. Some external hemorrhoids can be seen directly from the outside, while others are slightly deeper and need to be peeled away from the anus to be seen. In this case, the hemorrhoids are often only noticed when there is a sudden onset of thrombosed external hemorrhoids.