Piriformis syndrome is a common cause of low back pain that mimics the pain caused by sciatica or a herniated disc.  The piriformis is a muscle that is located in the area of the buttocks.  Its function is to rotate the leg outward at the hip.  With trauma or overuse, the muscle can become inflamed or irritated.  The belly of the muscle can compress the sciatic nerve and cause symptoms similar to those of a herniated disc or sciatica.  The pain is located in the lower back area and can radiate down the leg.  The pain can cause alterations is gait and posture leading to additional lower back pain and hip pain.  EMG studies can determine if the pain is due to a piriformis problem or if it is coming from a herniated disc.  The treatment of piriformis syndrome begins with conservative modalities that include non-steroidal anti-inflammatories, heat, ice and other physical modalities.  For patients who do not respond to these interventions, injections into the muscle of a dilute solution of a local anesthetic combined with a steroid can be very helpful.