The internal carotid artery siphon segment is an artificial division of the internal carotid artery into seven segments, one of which is called the internal carotid artery siphon segment because it is shaped like a siphon, just like a bend in a tube. It is just a segment of the internal carotid artery and has no special meaning, but is shaped more like a bend in a tube that may produce a siphon. It usually travels inside the skull or cavernous sinus, and rarely appears as a special lesion. However, once an abnormal lesion appears, the area is often very difficult to treat, for example, sometimes a blister-like aneurysm may appear, which cannot be completely treated by craniotomy, and can only be treated by vascular interventions such as double stents or overlapping stents, and the cost is relatively high. The cost is relatively high. Therefore, it is important to detect and treat the siphon segment of the internal carotid artery early, as it is only a segment of the blood vessel and has no special meaning.