Hemorrhoids are soft venous masses formed by the expansion and bending of the venous plexus under the mucosa of the end of the rectum and the skin of the anal canal. They are more common in people who often stand or sit for a long time. Hemorrhoids include internal hemorrhoids, external hemorrhoids, and mixed hemorrhoids. They are a chronic disease in which the venous plexus at the bottom of the anorectum and the anal mucosa becomes varicose and forms one or more soft venous masses. Usually, when you continue to exert force during defecation, the pressure in the veins here will repeatedly increase, and the veins will swell. Women often develop hemorrhoids during pregnancy due to compression of the pelvic veins, which hinders blood circulation. Many obese people also suffer from hemorrhoids. If you have hemorrhoids, the swollen and twisted vein walls in the anus will become very thin, so they are very easy to rupture during defecation. Internal hemorrhoids are hemorrhoids that grow at the beginning of the anal canal. If the swollen veins are located further down, almost at the anal canal opening, this varicose vein is called an external hemorrhoid. External hemorrhoids sometimes prolapse or appear outside the anal canal opening. But this only happens when you defecate, and it will shrink back to its original position after defecation. Whether it is internal or external hemorrhoids, thrombosis may occur. When a thrombosis occurs, the blood in the hemorrhoids clots into a mass, causing pain.