Buttock pain keeps coming back ? In Rolfing Structural Integration we look farther afield.
The piriformis muscle is conventionally described as a hip rotator as it turns the leg and foot outward, but it does more.
When the thigh is free to move (when we lift a leg off the floor), indeed contracting the piriformis results in lateral rotation of the thigh. However when we stand firmly on the ground, the thighs are fixed, the piriformis muscles become stabilisers and adjusters of the spine.
The piriformis muscle is located between the base of the spine (sacrum) and the lateral sides of the femur bone. When it spasms it causes buttock pain. It can irritate the sciatic nerve which passes nearby and cause pain along the back of the leg.
In chronic lateral deviations (scoliosis) or rotations of the spine, the piriformis located on the same side of the deviation is chronically tight and eccentrically loaded. In Rolfing Structural Integration, for long term release of tight piriformis syndrome and possible associated sciatic pain, Rolfers also look at lateral deviations and rotations of the spine, otherwise tightness in the piriformis area will come back.