The dentate line of the anus is called the dentate line of the anal canal in medicine, which is a circular giant tooth-like line located 2-3 cm inside the anus, and is the dividing line between the rectum and the anal canal of the human body. The rectum above the dentate line is innervated by the vegetative nerve and the blood supply comes from the inferior mesenteric artery, while the tissue below the dentate line is innervated by the spinal nerve and the blood supply comes from the iliac vessels. There are also anatomical tissues on the dentate line, such as the anal fossa, the anal flap, etc. The dentate line can also be used to distinguish between the types of hemorrhoids, with those above the dentate line being internal hemorrhoids and those below being external hemorrhoids.