... is a condition which is believed to result from compression of the sciatic nerve by the piriformis muscle. ... Causes may include trauma to the gluteal muscle, spasms of the piriformis muscle, anatomical variation, or an overuse injury. ... Most practitioners agree that spasm, strain or pain in any muscle can often be treated by regular stretching exercise of that ... Piriformis syndrome may also be associated with direct trauma to the piriformis muscle, such as in a fall or from a knife wound ...