The piriformis muscle is a flat, band-like muscle located in the buttocks near the top of the hip joint. It stabilizes the hip joint and lifts and rotates the thigh away from the body. The piriformis enables us to walk, shift our weight from one foot to another, and maintain balance. It also is used in sports that involve lifting and rotating the thighs.
The sciatic nerve is a thick, long nerve in the body. It passes alongside or goes through the piriformis muscle, goes down the back of the leg, and eventually branches off into smaller nerves that end in the feet. Piriformis syndrome is an uncommon neuromuscular disorder caused when the piriformis muscle compresses the sciatic nerve.
Warning Signs & Symptoms
Piriformis syndrome usually starts with pain, tingling or numbness in the buttocks. Pain can be severe and extend the length of the sciatic nerve. The pain is due to the piriformis muscle compressing the sciatic nerve during activities like sitting in a car or running. Pain also may be triggered while climbing stairs, applying firm pressure directly over the piriformis muscle, or sitting for long periods of time. Most cases of sciatica, however, are not due to piriformis syndrome.
Possible Risk Factors
Shortening of the muscle and compression of the nerve is the most common cause of piriformis syndrome, but overuse of the glutes and other muscles in the hip also can cause muscle spasms of the piriformis. Other factors in this syndrome include poor body mechanics and posture and gait problems.
Pain also can be caused by prolonged external rotation of the hip, something that is common in ballet dancers so that the piriformis muscle is shortened. If the sciatic nerve is compressed for a long time, there may be aching in the leg and pain in the low back.
Tests to Diagnose Piriformis Syndrome
There is no definitive test for piriformis syndrome. In many cases, there is a history of trauma to the area: repetitive, vigorous activity such as long-distance running or prolonged sitting. Diagnosis of piriformis syndrome is made by the patient’s report of symptoms and by physical exam using a variety of movements to elicit pain to the piriformis muscle. In some cases, a contracted or tender piriformis muscle can be found during a physical exam.
Because symptoms can be similar to other conditions, tests such as MRIs may be needed to rule out other conditions, such as a herniated disc.
Stretching and strengthening are the best treatments for piriformis syndrome. This muscle rarely gets stretched, so a simple stretching routine can often work wonders.
If pain is caused by sitting or certain activities, try to avoid positions that trigger pain. Rest, ice and heat may help relieve symptoms. A doctor or physical therapist can suggest a program of exercises and stretches to help reduce sciatic nerve compression. Osteopathic manipulative treatment has been used to help relieve pain and increase range of motion.
Some doctors may recommend anti-inflammatory medications, muscle relaxants or injections with a corticosteroid or anesthetic. Other therapies, such as iontophoresis, which uses a mild electric current and injection with botulinum toxin, may help relieve muscle tightness and sciatic nerve compression to minimize pain. Surgery may be recommended as a last resort.
Since piriformis syndrome is usually caused by sports or movement that repeatedly stresses the muscle, prevention often is related to good form. Avoid running or exercising on hills or uneven surfaces. Warm up properly before activity, and increase intensity gradually. Use good posture while running, walking or exercising. If pain occurs, stop the activity and rest until pain subsides.