Pyriformis syndrome is sometimes mild and sometimes severe because the sciatic nerve is sometimes irritated by entrapment and sometimes not compressed due to factors such as changes in position. The pyriformis syndrome is due to compression of the sciatic nerve. The sciatic nerve passes through the outlet of the pyriformis muscle, and most patients suffer from long-term chronic strain injury to the pyriformis muscle, local congestion and edema or spasm, and repeated injuries cause hypertrophy of the pyriformis muscle, resulting in narrowing of the outlet, which leads to the sciatic nerve being compressed, causing the pyriformis syndrome. If you reduce the activity, after sufficient rest, treatment, etc., the edema of the pyriform muscle can be significantly reduced, no narrowing of the sciatic nerve outlet of the pyriform muscle, the sciatic nerve compression is reduced or not compressed, and then the symptoms of the pyriform muscle syndrome are also reduced. If the pyriform muscle edema or position changes after activity re-entraps the nerve, the symptoms worsen. If the diagnosis of pyriformis syndrome is clear, systematic treatment should be prescribed.