Sit down to appear buttock pain, may be the following aspects of the reason: the first may be the bursitis of the sciatic node, this situation is usually a sterile inflammation, because often sit for a long time, the sciatic node is often subjected to pressure and stimulation, resulting in aseptic inflammation, usually in the place of the sciatic node, there is a very obvious point of pressure and pain. The second possibility is that the sciatic tuberosity cyst, usually can touch the local buttock sciatic tuberosity position has a lump, and this lump is oval, can be movable, usually because of frequent sitting to stimulate the sciatic tuberosity place, resulting in synovial sac stimulation and cysts, usually can do local ultrasound, basically can be diagnosed. The third may be sitting for a long time leading to some ischemic inflammatory pain in the buttocks, this situation can usually be localized by rubbing, local hot compresses, the symptoms will soon be relieved.