The piriformis muscle is a large flat muscle in the buttock area lying deep to the gluteal muscles. It originates from the pelvis (sacrum) and attaches to the leg bone (femur). This muscle acts to abduct the thigh (move the leg out to the side) as well as rotating the leg.The sciatic nerve is a large nerve that originates from the lower spine and travels along the back of the leg to control muscles of the leg and supply sensation to the leg. The sciatic nerve usually passes underneath the piriformis muscle in the buttock area. In a small percentage of the population the nerve passes through the muscle.
In piriformis syndrome, it is thought that the piriformis muscle is tethering the sciatic nerve, causing irritation in the nerve which results in symptom production. It is believed that patients in which the nerve passes through the muscle are predisposed to this condition. Some common causes of piriformis muscle irritation includes blunt trauma leading to muscle spasm or contracture, chronic muscle injury due to impaired mechanics at the knee or foot, such as overpronation, leading to overuse.Symptoms of piriformis syndrome include pain in the buttock and down the back of the leg. This pain is made worse by placing the piriformis muscle on a stretch, with repetitive use of the muscle, or by applying compression or weight to the buttock such as sitting. Piriformis muscle spasm and tenderness to touch is often found on examination.
A multidisciplinary intervention involving a physician, physiotherapist and massage therapist is often beneficial.
Piriformis syndrome treatment often consists of:
- Rest: avoid activities that trigger symptoms.
- Anti-inflammatory medication: to decrease inflammation of the muscle.
- Stretching: for the piriformis muscle (see below).
- Strengthening: for the rotators of the hip (see below).
- Deep massage: to release the piriformis muscle.
- Address abnormal mechanics: of the knee and foot to take the stress off the piriformis muscle.
- Corticosteroid injection: in chronic conditions, this may be tried.
- A thorough assessment of the lower limb and back is necessary to diagnose this syndrome, rule out other possible causes of similar pain and to develop an individualized treatment plan to allow your to return to pain free activities.
Piriformis muscle stretch:
Lie on your back with your knees bent and feet flat on the ground. Cross the affected leg so that the ankle is resting on the unaffected knee. Grasp the unaffected leg with your hands and pull the leg in towards your chest until a stretch is felt in the buttock area of the crossed leg. Hold the stretch for 30 seconds.
Piriformis muscle strengthening:Lie on your side with the affected leg on top. Keep your hips stacked, knee straight and leg in line with your body. Lift the leg towards the ceiling, hold for a count of 3 to 5, return and repeat.
References available upon request