Piriformis Syndrome is caused by an entrapment (pinching) of the sciatic nerve as it exits the Greater Sciatic notch in the gluteal region. There are two normal variations for the exit of the sciatic nerve in this region. The first places the sciatic nerve inferior (below) to the Piriformis muscle and superior (above) the gemellus muscle. Entrapment in this area is likely due to a myospasm or contracture (tightening or shortening respectively) of either of these two muscles.
The second common site of entrapment is when the sciatic nerve actually pierces the piriformis muscle itself. This can occur in about 1% to 10% of all humans. In this case myospasm and or contraction of the piriformis muscle itself can lead to pain along the back of the thigh to the knee, loss of sensation or numbness and tingling in the sole of the foot. This particular syndrome can often mimic its more notorious counterpart known as sciatica, and that being the case, it is often misdiagnosed as sciatica. The main difference between sciatica and piriformis syndrome is in the cause. Sciatica is directly due to a lumbar disc pressing on the sciatic nerve as it exits the intervertebral foramen in the lumbar spine. What both of these complaints have in common is that both can produce pain, numbness and tingling below the knee and into the foot.
Signs and Symptoms
Deep aching in the buttock and thigh on the involved side. Usually not beyond the knee.
Pain is often aggravated by sitting, squatting or walking.
Affected leg is often externally rotated (toes point out) when relaxed, such as when lying face down on the bed with your feet over the end of the mattress.
Right leg often affected after driving a long distance if the foot has been in external rotation while depressing the gas pedal.
Often causes low back pain
Some reports suggest a 6:1 female to male predominance
Often the patient may not be aware that there is a problem. Some cases won't show up until a complete neurological exam is performed on the lower extremity. The patient may have chief complaints ranging from no pain to pain in the lower back to gluteal pain to numbness and tingling in the foot. As can be seen the symptoms in this condition can vary widely making the doctor who is not used to differentially diagnosing this condition from sciatica confused as to the cause of the condition.
Many weekend athletes and people who spend long hours sitting are prone to this syndrome. The athlete's cause is primarily due to improper stretching and warm-up exercises as well as overuse during activity. In this case it is most likely that the piriformis muscle is irritated and usually in spasm.
For the patient who sits for extended periods of time, their primary cause is due to contracture of the piriformis muscle. In this case the piriformis muscle is shortened and does not allow for the smooth movement of the sciatic nerve during leg motion. A one-time direct trauma to the pelvis is very rarely a cause for piriformis syndrome due to the protection afforded the pelvis by the overlying musculature and fat. The causes of myospasm are many. Over use as during excessive fast walking without proper warm up and stretching (as during exercise), prolonged sitting, as for your treatment, many variables can hamper your successful recovery. Smoking, obesity, job and exercise as noted above in prolonged sitting and not warming up and stretching.
Any treatment plan must include stretching of the gluteal muscles as well as stretching of the piriformis muscles. Your Chiropractor can help you by instructing you on the proper exercises and stretches to perform. Many Chiropractors may also prescribe some form of massage be performed to the piriformis muscle in the gluteal region in order to relax these muscles.
Your chiropractor may also prescribe certain herbals remedies such as valerian root and passion flower to help relax the associated muscles during your recovery phase. Spinal adjustment as well as hip adjustment may also be required to eliminate the problem.