The piriformis muscle is located in the buttocks, originating from the lower spinal column and attaching to the back of the thighbone, or femur. The sciatic nerve runs under the piriformis muscle. Piriformis syndrome occurs when this muscles spasms or becomes tight, states MayoClinic.com. Piriformis is often treated with conservative treatments such as medications or physical therapy.
Prolonged Sitting
Prolonged sitting is a common cause of piriformis syndrome, states MayoClinic.com. Prolonged sitting places pressure on the muscle for an extended period of time, which can cause the muscle to become tight or spasm. Therefore, frequent breaks from sitting are necessary to prevent the piriformis muscles from going into a spasm. In addition, well-cushioned seating should be used if prolonged sitting is expected.
Trauma
Injury can occur to the piriformis muscle and contribute to piriformis syndrome. Examples include car accidents, sports injuries or falls onto the buttock. Eorthopod.com states that injury to the piriformis muscle results in bleeding, or a hematoma, that pools around the piriformis. The piriformis muscle swells and can aggravate the sciatic nerve. Over time, the piriformis muscle can form scar tissue and become tight, resulting in chronic piriformis syndrome. Therefore, safety precautions should always be followed, and the proper equipment and technique should be used in sports.
Unprovoked Spasm
In some cases, the cause of piriformis syndrome cannot be identified. Eorthopod.com states that the piriformis muscle may begin to spasm without a known cause. This causes irritation of the sciatic nerve as the piriformis muscles compress the sciatic nerve against the pelvis bone. To reach this diagnosis, a doctor must rule out other causes of piriformis injury and other causes of sciatic nerve compression. A complete history will be taken and physical exam performed. X-rays or MRI may be ordered to see if there is any notable injury or inflammation of the piriformis muscle. In addition, Eorthopod.com states that a doctor may inject a chemical "tracer" into the piriformis muscle and use a bone scan machine to assess injuries. The most accurate means of diagnosis, however, is to inject medication directly into the piriformis muscle. If symptoms improve, piriformis syndrome is the likely cause.
