Muscle · Core

Psoas minor

Musculus psoas minor

A slender muscle lying on the front of psoas major, with a small belly high up and a long flat tendon that makes up most of its length. It runs from the bodies of the twelfth thoracic and first lumbar vertebrae down to the pubis, near the ridge where the pelvic brim runs forward. The crucial point is where it does NOT go: unlike psoas major beside it, it never reaches the femur, so it cannot flex the hip. All it can do is bend the lower spine forward slightly on the pelvis. It is absent in a large minority of bodies, and its absence changes nothing functionally — which is the best evidence there is for how little it does.