The Piriformis Muscle is located behind the hip joint in the gluteal region or buttocks. The Piriformis Muscle is small in comparison to other the other muscles around the hip and thigh. This muscle assists in external rotation of the hip joint such as when you turn your foot/toe out.
The piriformis muscle and the tendon that it attached to are in close proximity to the sciatic nerve which is the largest nerve in the body and powers your lower extremities with motor and sensory function. The piriformis tendon and sciatic nerve cross each other behind the hip joint, in the deep buttock.
Inflammation and related muscle of the piriformis muscle can put pressure on the sciatic nerve. When this happen tingling, numbness and pain can be felt in the gluteal region. This pain may get worse when sitting and at times the pain can travel down the legs. Sometimes it is difficult to differentiate piriformis syndrome from sciatica or lumbar radiculopathy.