Deep Lateral Rotator Group

Joe Muscolino

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The deep lateral rotator group of the pelvis/hip joint. The deep lateral rotators are: piriformis, superior gemellus, obturator internus, inferior gemellus, obturator externs, quadratus femoris.

The Deep Lateral Rotator Group is composed of the following six muscles (from superior to inferior):

  • Piriformis
  • Superior gemellus
  • Obturator internus
  • Inferior gemellus
  • Obturator externus
  • Quadratus femoris

ATTACHMENTS:

  • The deep lateral rotator group attaches from the sacrum (piriformis) and the pelvic bone (the rest of the group) to the (or nearby the) greater trochanter of the femur.
  • Note: The obturator externus sits deeper than the other muscles of the group, lying wholly or mostly deep to the quadratus femoris.

 

ACTIONS:

  • As a group, the deep lateral rotators laterally rotate the thigh at the hip joint and contralaterally rotate the pelvis at the hip joint.
  • If the thigh is first flexed to 90 degrees, the deep lateral rotators can horizontally extend (horizontally abduct) the thigh at the hip joint.
  • Note: If the thigh is first flexed (approximately 60 degrees or more), the piriformis changes to become a medial rotator of the thigh at the hip joint instead of a lateral rotator.