Piriformis syndrome is a rare neuromuscular disorder that occurs when the piriformis muscle compresses or irritates the sciatic nerve-the largest nerve in the body. The piriformis muscle is a narrow muscle located in the buttocks. Compression of the sciatic nerve causes pain-frequently described as tingling or numbness-in the buttocks and along the nerve, often down to the leg. The pain may worsen as a result of sitting for a long period of time, climbing stairs, walking, or running.
The prognosis for most individuals with piriformis syndrome is good. Once symptoms of the disorder are addressed, individuals can usually resume their normal activities. In some cases, exercise regimens may need to be modified in order to reduce the likelihood of recurrence or worsening.