10 Piriformis Stretches - The sciatic nerve is located deep in the buttock. Because of its vicinity to the piriformis muscle, constriction or swelling of the muscle may lead to irritation of the nerve and pain.
Piriformis syndrome is a type of painful neuromuscular disorder that affects the hips, butt and thighs. It’s caused from spasms in the small piriformis muscle compressing against the sciatic nerve, a thick nerve that runs down the length of the legs.
A great site dedicated to the piriformis. Another Pinner posted: How to detect piriformis syndrome and a specific strengthening and stretching program to help you return to healthy training psoas strengthening runners
Your Lower Back Pain Could Mean You Have Piriformis Syndrome