Spine Specialists define Piriformis syndrome as a neuromuscular disorder caused by the piriformis muscle compressing the sciatic nerve. The flat band of piriformis muscle located in the buttocks sits at the top of the hip joint, and the thick sciatic nerve passes through the piriformis muscle, runs down through the leg, and branches off into smaller and smaller nerve endings in the feet. When Piriformis syndrome causes the piriformis to press on the sciatic nerve, patients usually report feeling pain, tingling, or numbness in the buttocks. Patients may also experience pain when climbing stairs, sitting down for an extended period of time, or when pressing directly on the piriformis muscle. In spite of all of this, Piriformis Syndrome does not commonly present as the cause of sciatica.