There is still considerable debate about the existence of a problem called piriformis syndrome. With this syndrome, there is buttock and/or leg pain caused by irritation of the sciatic nerve.
It’s called piriformis syndrome because the sciatic nerve passes through the piriformis muscle. The piriformis muscle is located deep in the buttock. Muscle spasm, scar tissue, or other changes in the soft tissue put pressure on the nerve causing pain, numbness, tingling, and weakness.
Often nerve conduction velocity (NCV) tests and imaging studies are within normal limits. Since there’s no way to prove there is such a problem as piriformis syndrome, the diagnosis is still questioned by some experts. There’s no question the patient is having symptoms, but the cause of the problem isn’t always clear.