Piriformis syndrome is commonly referred to as pain in the butt. The patient often complains of buttock pain and pain in the back of the leg down to the knee with a nontraumatic onset.
The sciatic nerve may be compressed by the piriformis muscle. In most patients, the sciatic nerve runs under the muscle; however, in approximately 15% of the population, there are two muscle bellies with the sciatic nerve. Piriformis syndrome is often found in distance runners such as marathoners and triathletes, and it is most commonly due to poor arch support.