If the patient has a painful situation of lying on the buttocks, it may be due to local ischemia, hip muscle fatigue and other reasons, as follows: First, local ischemia: some patients are bedridden for too long or the bed board is too hard, resulting in local ischemia, which then leads to pain. In the process of prolonged bed rest, such patients may cause excessive pressure on the surrounding soft tissues by the bony protrusion of the sacrococcygeal area, which will cause ischemic lesions to appear in the relevant parts, and then produce pain. If the lesion is serious, pressure sores may appear. Second, fatigue of the hip muscles: some patients may have symptoms due to fatigue of the hip muscles, for example, after standing for a long time, which may have caused fatigue of the hip muscles, and after lying in bed for a period of time, due to the gradual appearance of edema and lactic acid deposition in the muscles, they may suddenly feel soreness in the hip.