The demarcation line between internal and external hemorrhoids is called the dentate line, which is a relatively important anatomical structure around the anus and is an important demarcation line. Above the dentate line is the rectal mucosa, and below the dentate line is the skin of the anal canal, which is also the dividing line between the rectum and the anal canal. Above the dentate line is innervated by the vegetative nerves and there is no pain sensation. However, it is more sensitive to the sensation of distension and traction. Below the dentate line is the skin of the anal canal, which is innervated by the pubic nerves and is more nerve sensitive. Hemorrhoids that grow above the dentate line are called internal hemorrhoids and those that grow below the dentate line are called external hemorrhoids. Internal hemorrhoids are mainly bleeding and swelling prolapse, the bleeding is painless, manifested as dripping blood during stool, and more bleeding may appear as jet bleeding. External hemorrhoids are mainly painful, because the nerves on the surface are more sensitive and mainly present swelling pain.