A patient complains to a physician of chronic pain and tingling of the buttocks. The pain is exacerbated when the buttocks are compressed by sitting on a toilet seat or chair for long periods. No lumbar pain is noted. Pain is elicited when the physician performs Freiberg&;s maneuver. Most likely diagnosis

piriformis syndrome.: As you may recall from your anatomy, the piriformis is the small muscle that crosses the greater sciatic foramen, cutting it into two spaces as the muscle passes from the edge of the sacrum to the greater trochanter. The sciatic nerve comes out of the greater sciatic foramen below the piriformis, and is liable to compression by the muscle. Symptoms are as described above; bicycle riding and running may also set off the symptoms, which may take the form of chronic nagging ache, pain, tingling, or numbness. Treatment is usually to teach the patient to avoid maneuvers that set off the symptoms. Some patients have been helped by coicosteroid injection near the site where the piriformis muscle crosses the sciatic nerve; this therapy is thought to work by reducing the fat around the muscle and thereby increasing the available space in the area. Disk compression of the sciatic nerve can also produce sciatic pain, but there is almost always lumbar as well as buttock pain. Fibromyalgia causes achy pain, tenderness, and stiffness of involved sites, including muscles, tendon inseions, and nearby soft tissues. Sites commonly involved include head, neck, shoulders, thorax, low back, and thighs. Popliteus tendinitis is inflammation of the tendon of the popliteus muscle of the knee. Posterior femoral muscle strain produces pain in the posterior thigh on jumping. Ref: maheswari 9th ed