Piriformis

Joe Muscolino

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The piriformis of the deep lateral rotator group has been drawn in bilaterally. The gluteus medius and superior gemellus have been ghosted in on the left side.

The Piriformis is a member of the Deep Lateral Rotator Group (also known as the Deep 6), composed of the following six muscles (from superior to inferior):

ATTACHMENTS:

  • The piriformis attaches from the sacrum to the greater trochanter of the femur.
    • The proximal/medial attachment is onto the anterior surface of the sacrum.

 

ACTIONS:

  • Laterally rotates the thigh at the hip joint.
  • Medially rotates the thigh at the hip joint (if the thigh is first flexed approximately 60 degrees or more).
  • Abducts the thigh at the hip joint.
  • Horizontally abducts the thigh at the hip joint.
  • Contralaterally rotates the pelvis at the hip joint.

NOTE: A tight piriformis can compress the sciatic nerve causing symptoms of sciatica. When this occurs, it is called piriformis syndrome.