Piriformis Muscle and the Sciatic Nerve The piriformis muscle is small and located in the buttock, behind the gluteus maximus. The sciatic nerve runs underneath or through it. Further Reading: Piriformis Syndrome Related Articles Symptoms and Diagnosis of Piriformis SyndromePiriformis Muscle Stretch and Physical Therapy Related Videos Piriformis Syndrome VideoPiriformis syndrome is an irritation of the sciatic nerve caused by the contraction of the piriformis muscle.Sciatica Exercises for Piriformis Syndrome VideoAn informative visual demonstration of correct exercises and stretching techniques to help relieve sciatica pain caused by piriformis syndrome. Sciatica Animated VideoSciatica is leg pain caused by a problem in the low back. Watch an animated video that details the causes and symptoms of sciatica.