Medical Definition of Psoas

  • Medical Author:
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

Psoas: Two muscles of the lower back. There are two psoas muscles on each side of the back. The larger of the two is called the psoas major and the smaller the psoas minor. The psoas major originates at the spine, around the bottom of the rib cage, and runs down to the thighbone (the femur). The psoas major acts to flex the hip. The psoas minor also originates at the spine, around the bottom of the rib cage, but it runs down to the bony pelvis. The psoas minor acts to flex the lower (lumbar) spine.

Reviewed on 9/7/2018

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