Piriformis syndrome, which is a diagnosis, can literally be referred to as a “pain in the butt.” It describes an occurrence of buttock pain with specific tenderness in the center of one side of the buttock area. This pain can also radiate to the back of one thigh.
The word “piriformis” refers to a small muscle under the larger gluteal muscles that make up the contour of the buttock. It turns the hip and leg outward. The piriformis runs horizontally between the sacroiliac joint (part of the pelvis) to the outside of the hip (roughly where the top half of the back pocket of a pair of jeans would be).
The sciatic nerve, which exits the pelvis under the piriformis muscle, supplies feeling to the back and side of the leg. In some cases, this nerve is pinched by tightness or spasm in the piriformis muscle, resulting in pain to the buttock and in back of your thigh. This is also referred to as sciatic pain.
While it is difficult to isolate a single muscle as the root of a problem such as leg pain, many runners will be familiar with piriformis syndrome if they read running and other sports magazines.
Other types of problems can mimic piriformis syndrome. For example, a herniated disc can produce similar symptoms, but usually pain will be increased when flexing forward. Also, with disc problems, specific neurological tests usually show loss of reflexes and changes in sensation and strength.
There are several different causes of piriformis syndrome.
First and least common can be an abnormality in the structure of the pelvis that makes it more likely for the sciatic nerve to get pinched. For example, a cyst can compromise the area where the sciatic nerve comes out. This is rarely seen clinically.
Second, over use of the hip rotator can cause the piriformis muscle to inflame and swell. In runners, external rotators like the piriformis help your body compensate for changes in terrain or when you run on a slanted road. It also controls excessive flattening or pronation of the feet. This is why it is always important to replace running shoes every 6 months or at the first sign of wear that changes the shape of the back of the shoe or heel. It is well to avoid running on surfaces that aren’t banked so that one leg doesn’t land lower than the other one.
The last cause for piriformis syndrome is a problem with the sacroiliac joint. The sacrum is a triangular bone at the base of the spine. It is wedged between the right and left pelvic bones, which are called the iliums. Both the left and right piriformis muscles attach to the front of the sacrum, and one of them contracts with each step forward. If the sacroiliac joint becomes stuck while rotated in a certain position, the piriformis muscle on one side can spasm. Since some sacroiliac problems can be long standing, the spasming piriformis can lead to piriformis syndrome.
Treatment of the syndrome depends largely on the problem’s cause. Stretching and doing low back exercises for sacroiliac mobility may help. If the problem persists, an evaluation by a physical therapist to assess the situation may be appropriate after a visit to the doctor.
Remember, you don’t have to put up with that nagging pain in the buttock!