The Piriformis syndrome is a pressure on the sciatic nerve caused by an enlarged or inflamed piriformis muscle. A painful condition arises if the sciatic nerve is compressed between the Piriformis muscle fibers and the pelvic bones, or if the piriformis muscle is contracted with adhesions due to injury. The pain can radiate from the sacrum to the hip joint, into the buttock and posterior thigh.

Irritation of the Piriformis muscle can also cause Coccydynia, (tail bone pain) or dyspareunia, (painful intercourse). The main function of the Piriformis muscle is to externally rotate the hip; pain may be increased with sitting or squatting. The patient may notice that when lying on their back that the foot on the involved side rotates laterally while the other foot remains straight.

Piriformis muscle contracture may also cause the involved limb to shorten. Pain is reproduced when trigger points within the Piriformis muscle and surrounding gluteal muscles are pressed, or when the muscle is stretched by externally rotating the hip. Women are 6 times more likely to have Piriformis syndrome than men. Piriformis syndrome wcan mimic other causes of sciatic pain such as herniated discs, arthritis, infection or tumor. Piriformis syndrome is treated by stretching the muscle, friction massage, trigger point therapy, ultrasound, electrical muscle stimulation, and adjustments to the low back and pelvic joints.