What Are The Warning Signs And Causes Of Piriformis Syndrome?

Hematoma

A collection of blood or a hematoma in the piriformis muscle can cause an individual to experience piriformis syndrome. A hematoma can occur in a muscle when a vein or artery wall becomes injured. The injured vessel leaks blood into the surrounding tissues and begins to clot. The clotting blood that is displaced causes damage to neighboring cells. This damage summons an inflammatory response to the hematoma. The swelling that occurs as a result of the inflammatory response can cause the sciatic nerve to become compressed by the piriformis muscle. Because clotted blood is not a soft and pliable substance, the clot itself may be large enough to compress the nerve. A hematoma can also cause the leakage of other fluids into surrounding tissues or edema. Edema places more pressure on the muscle and takes up space while also pressing on neighboring blood vessels and nerves. Edema from a hematoma can displace the piriformis muscle, causing it to press down on the affected individual's sciatic nerve. It is a combination of one or more of these mechanisms that can cause an individual to experience piriformis syndrome.