Human Movement Science & Functional Anatomy of the:

Piriformis

by Brent Brookbush MS, PES, CES, CSCS, ACSM H/FS

Pirformis Posterior View Piriformis Image - Gray's Anatomy 20th Edition via Bartleby.com, found on wikimedia.com

Anatomy:

  • Origin: Anterior surface of the sacrum between (and lateral to) the first through the fourth sacral foramina, margin of the grater sciatic foramen and pelvic surface of the sacrotuberous ligament (11).
  • Insertion: Superior border of the greater trochanter of the femur.

    • The pirformis lies deep to the gluteus maximus.  The insertion of the piriformis lies on the Superior aspect of the greater trochanter between the insertions of the gluteus minimus and gluteus medius, the lateral aspect of this muscle lies superficial to the sciatic nerve and the muscle becomes progressively deeper as it traverses through the greater sciatic notch of the ilium, and invests in the anterior surface of the sacrotuberous ligament and anterior sacrum. This muscle is bordered inferiorly by the gemellus Superior superficially, and the coccygeus on the anterior surface of the sacrum.

      • This muscle may be palpated by finding the spinous process of S2 with your thumb (the first prominent spinous process on the sacrum), and finding the greater trochanter with your index finger.  The nearly horizontal line between these two points should outline the piriformis. Sinking your fingers deep to the gluteus maximus and running your fingers gently up and down should result in the relatively thin band like