Psoas

[Sarah]

An internal muscle arising from the lumbar vertebræ andinserted into the femur. In man there are usually two on each side,and the larger one, or great psoas, forms a part of the iliopsoas.

[Michiko]

one of the two muscles on each side of the body that go from each side of the spine to the top of the thigh bone

[Lizzy Liz]

Each of a pair of large muscles which run from the lumbar spine through the groin on either side and, with the iliacus, flex the hip. A second muscle, the psoas minor, has a similar action but is often absent.