The piriformis muscle is a structure that lies beneath the larger gluteus maximus muscle in each buttock. The piriformis extends from the base of the spine where it connects with the top of each femur (thigh bone). The sciatic nerve is a major nerve pathway that extends from the spine to the pelvis and travels directly beneath the piriformis, as it continues into each leg and foot. The piriformis is a part of the muscle complex that permits the hip to rotate.
Piriformis syndrome is characterized by pain that is experienced deep in the buttock, often radiating into the lower back and the legs, occasionally as far as the foot on the affected side of the body. Until recently, piriformis syndrome was not widely accepted as a distinct physical condition within the sports medicine community, as it was believed to be a type of sciatica, the well-known inflammatory condition of the sciatic nerve. Sciatica has a cause distinct from that of piriformis syndrome in that it occurs due to pressure on the nerve canal where the sciatic nerve exits the spine at the top of the pelvis. The piriformis syndrome is most evident to an affected person when walking, running, sitting for extended periods of time, climbing multiple sets of stairs, or performing any movement involving a squat or deep knee bend.
Piriformis syndrome results from either a tightness developing in the muscle structure itself, or through the combined effects of muscle tightness and pressure being applied to the underlying sciatic nerve. A number of other musculoskeletal conditions may exist concurrently with piriformis syndrome, the most common of which are unequal leg length, which directs unequal pressures into each leg, and weak abductor muscles, which control the ability of the legs to spread apart.
When piriformis syndrome is identified, the first course of treatment prescribed to an athlete is usually rest for a period of two to three weeks. During the rest period, specialized stretches will often be recommended, movements that are designed to reduce the tightness of the piriformis in relation to the surrounding muscle structures. On a permanent basis, athletes often find that a commitment to a rigorous stretching and flexibility program is essential to prevent a recurrence of piriformis syndrome. Yoga and Pilates are two exercise systems that emphasize a number of different stretches that specifically target the buttocks and hips. In more severe cases, a corticosteroid may be injected directly into the affected piriformis to provide an anti-inflammatory effect. Ultrasound therapy may also be engaged. Surgery is a procedure that is rarely employed, given the position of the muscle and its proximity to the sciatic nerve.