Piriformis syndrome is a condition which is believed to result from compression of the sciatic nerve by the piriformis muscle. Symptoms may include pain and numbness in the buttocks and down the leg. Often symptoms are worsened with sitting or running. Causes may include trauma to the gluteal muscle, spasms of the piriformis muscle, anatomical variation, or an overuse injury. Few cases in athletics, however, have been described. Diagnosis is difficult as there is no definitive test. A number of physical exam maneuvers can be supportive. Medical imaging is typically normal. Other conditions that may present similarly include a herniated disc. Treatment may include avoiding activities that cause symptoms, stretching, physiotherapy, and medication such as NSAIDs. Steroid or botulinum toxin injections may be used in those who do not improve. Surgery is not typically recommended. The frequency of the condition is unknown, with different groups arguing it is more or less common. Signs and symptoms The signs and symptoms include gluteal pain that may radiate down buttock and the leg, and that is made worse in some sitting positions. Etiology Causes of piriformis syndrome include the following Anatomic anomalies, present since birth: Bipartite piriformis muscle Sciatic nerve course/branching variations with respect to the piriformis muscle: In over 80% of the population, the sciatic nerve courses deep to and exits inferiorly to the piriformis muscle belly/tendon. Early (proximal) divisions of the sciatic nerve into its tibial and common peroneal components can predispose patients to piriformis syndrome, with these branches passing through and below the piriformis muscle or above and below the muscle. Acquired Sitting for prolonged periods (office workers, taxi drivers, bicycle riders) Overuse syndromes: Piriformis muscle hypertrophy (viz., in athletes) Trauma to the hip or buttock area Pathophysiology When the piriformis muscle shortens or spasms due to trauma or overuse, it can compress or strangle the sciatic nerve beneath the muscle. Generally, conditions of this type are referred to as nerve entrapment or as entrapment neuropathies; the particular condition known as piriformis syndrome refers to sciatica symptoms not originating from spinal roots and/or spinal disc compression, but involving the overlying piriformis muscle. In 17% of an assumed normal population the sciatic nerve passes through the piriformis muscle, rather than underneath it; however, in patients undergoing surgery for suspected piriformis syndrome such an anomaly was found only 16.2% of the time leading to doubt about the importance of the anomaly as