9. Piriformis
Origin: Anterior surface of the sacrum (approximately S2-S4) and sacrotuberous ligament
Insertion: Superior border of the greater trochanter of the femur
Action:
- Lateral rotation of the hip when the leg is straight
- Abduction of the leg when the hip is flexed
Innervation: Anterior rami of S1/S2

Needling
Position: Prone
Palpation: Palpate the lateral aspect of the sacrum and the greater trochanter
Technique:
-
- Needle towards the lateral aspect of the sacrum
- Needle towards the greater trochanter
Caution: Moderate: Avoid the middle 1/3rd of this muscle as the sciatic nerve travels under this portion of the piriformis


Video 2.9 Needling of piriformis, original video by Nadine Crocker, CC BY-NC 4.0.