Piriformis syndrome is a common condition that develops when there is a chain reaction of nerve irritation in your low back, buttocks and legs. It begins with an aggravated or strained piriformis muscle, which is a muscle in each of your buttocks. That muscle, in turn, irritates small surrounding nerves, which then irritate the larger sciatic nerve that runs from your low back through your buttock and into your leg.
Commonly, patients with piriformis syndrome complain about a deep pain in a buttock, but aren't able to describe exactly where the pain is coming from. Sitting, climbing stairs or performing squats can make the bothersome pain even worse.
Because the sciatic nerve supplies nerve function to the leg, patients may also experience pain that moves to the outside of the thigh or even as far as the foot. For that reason, piriformis syndrome is classified as a type of sciatica, which is a category of conditions that cause tingling sensations, burning sensations, shooting pain, prickling and numbness along the lower limb.
When there's no pain, people usually take piriformis muscles for granted, and don't realize that they're responsible for an extremely important movement: external hip rotation. To understand how the muscles work, picture a soccer player trying to kick or pass a ball with the inside of his foot. To perform this motion, he must rotate his leg about 80 degrees, so the foot is pointing outwards.
Without the piriformis muscle, this movement would be impossible. But a number of factors can interfere with the muscle, hindering performance and causing great pain. These include trauma to the sacroiliac joint (a joint in the pelvis that's comprised of two bones: the sacrum and the ilium), sitting with one leg crossed over the other, having one leg that's longer than the other, sitting or driving while one leg faces outward, improper walking, poor posture and faulty spine mechanics.
Hormones can also be a factor, and for that reason women are more prone to piriformis syndrome because they experience constant hormonal changes, such as those caused by menstruation, oral contraceptives, pregnancy and menopause. During pregnancy, for example, the body produces a hormone called relaxin to loosen ligaments around the pelvis in preparation for birth. The muscles around the pelvis, including the piriformis muscles, react by tightening up, forcing the piriformis muscles to work harder to stabilize the area.
With all these complications, and mostly because piriformis syndrome produces symptoms that are similar to other forms of sciatica, the condition can be very difficult to diagnose. Once a chiropractor determines the correct cause, however, he or she can provide effective care.