Muscle Anatomy of the Piriformis
Origin: Attaches to the pelvic surface of the sacrum between the anterior sacral foramina, the margin of the greater sciatic foramen, and the sacrotuberous ligament
Insertion: Attaches to the superior margin of the greater trochanter of the femur.
Actions: Assists with external rotation and abduction of the thigh
Innervation: Nerve to piriformis (S1, S2)
Blood Supply: Inferior gluteal artery from the internal iliac artery
Insertion: Greater trochanter
Action: External Rotation of the thigh
Innervation: Nerve to piriformis
Blood Supply: Inferior gluteal artery
Piriformis Muscle Actions With Agonists and Antagonists
Primary Actions of the Piriformis Muscle
The piriformis does not perform a primary action, it assists other muscles with movement of the thigh and hip stabilization.
Secondary Actions of the Piriformis:
1. Assists with external rotation of the thigh at the hip
- Obturator Internus
- Obturator Externus
- Gemellus Superior
- Gemellus Inferior
- Quadratus Femoris
- Tensor Fasciae Latae
- Gluteus Minimus (anterior fibers)
- Gluteus Medius (anterior fibers)
2. Assists with the abduction of the thigh at the hip when the hip is flexed
- Gluteus Maximus (upper fibers)
- Gluteus Medius
- Gluteus Minimus
- Adductor Longus
- Adductor Brevis,
- Adductor Magnus
Recommended Beginner Anatomy Books
The Anatomy Coloring Book is one of the best study and reference books for beginning anatomy students. The diagrams are clearly labeled and allow you to see the relationship and placement of the various structures of the body.
The Trail Guide To The Body is another excellent book to help you learn the musculature of the human body. Though the book is geared toward massage therapists and physical therapist assistants, the book with its illustrations and text helps anyone gain a thorough understanding of the human musculoskeletal system and movement. I highly recommend this book for anyone studying anatomy.
Twelve years of experience working with clients with chronic pain, post injury pain, and post surgery pain. Muscle dysfunction is often overlooked but can hold the key to many pain conditions.