Piriformis Anatomy: Origin, Insertion, Action, Innervation

Piriformis Anatomy Study

The piriformis anatomy
Origin: Anterior surfaces of the sacrum by three or four slips off the portions of bone between the foramina of the sacrum, the ilium near the posterior inferior iliac spine, the capsule of the sacro-iliac joint, and occasionally the upper part of the sacrotuberous ligament.
Insertion: By a rounded tendon to the upper part of the medial surface of the greater trochanter, occasionally blending with the common tendon of obturator internus, gemellus superior, and gemellus inferior.
Action: Assists with lateral rotation and abduction of  the thigh
Innervation: Nerve to piriformis (S1, 2)
Blood Supply: Inferior gluteal artery from the internal iliac artery

Synergist: Gluteus Maximus, long head of Biceps femoris, Sartorius, Gluteus medius, Gluteus minimus, Iliopsoas, Gemellus superior, Gemellus inferior, Quadratus femoris, Internal obturator, External obturator

Antagonist: Semitendinosus, Semimembranosus, Tensor Fasciae Latae, Pectineus


Primary Actions:

  • The piriformis does not perform a primary action, it assists other muscles with movement of the thigh and hip stabilization.

Secondary Actions

1. Assists with external rotation of the thigh at the hip

    • Agonists: Obturator Internus and Externus, Gemellus Superior and Inferior, Quadratus Femoris
    • Antagonists: 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

    • Agonists: Gluteus Maximus (upper fibers), Gluteus Medius, Gluteus Minimus
    • Antagonists: Adductor Longus, Adductor Brevis, Adductor Magnus

For pain and symptoms information see: Piriformis Muscle: Back, Hip, Buttock, Pelvic, Thigh Pain


Learn Anatomy With These Books

Musculoskeletal Anatomy Flashcards Musculoskeletal Flashcards Are you a student or professional therapist who needs to brush up on the musculoskeletal system? Dr. Joseph E. Muscolino DC has developed a comprehensive set of flashcards that will help develop a mind’s picture of exactly where the muscles lie under the skin. A highly recommended study aid for students. Great for non students who want an easy comprehensive anatomy guide.


basic_clinical_massa

 

Out of the scores of books in my office Basic Clinical Massage Therapy is by far the most referenced book in my library. The musculoskeletal system is overlaid on human models allowing you to learn the precise location, origin and insertions of each muscle. The models are pictured in various poses throughout the book which also helps you visualize muscles in motion and their actions relationship with the skeletal structure and other muscles. Though it is written for massage therapists, it is an excellent book for anyone who wants to learn about the muscular system. MT’s will benefit from recommended treatments for each muscle.


References:

The Trigger Point Therapy Workbook – Claire Davies, Amber Davies, and David G. Simons

Basic Clinical Massage Therapy: Integrating Anatomy and Treatment – James H. Clay and David M. Pounds

Trigger Point Therapy for Myofascial Pain – Donna Finando and Steven Finando

Massage Therapy Principles and Practice – Susan Salvo

Theory & Practice of Therapeutic Massage – Mark Beck

 

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