psoas Definition

either of two internal muscles of the loin:

psoas major

psoas minor

the larger of the two psoas muscles that arises from the anterolateral surfaces of the lumbar vertebrae, passes beneath the inguinal ligament to insert with the iliacus into the lesser trochanter of the femur, and serves especially to flex the thigh

the smaller of the two psoas muscles that arises from the last dorsal and first lumbar vertebrae and inserts into the brim of the pelvis, that functions to flex the trunk and the lumbar spinal column, and that is often absent

psoas