Iliopsoas is sometimes classified as two muscles, Iliacus and Psoas major, with Iliacus arising from the Ilium and Psoas from the vertebrae.
- Inner surface of the Ilium.
- Base of the sacrum.
- Sides of the bodies of T12-L5.
- Lesser trochanter of the femur.
- Flexion of the hip
- Lateral rotation of the hip.
- Flexes torso when the legs are fixed (e.g. laying to sitting).
- Femoral nerve and branches of the lumbar plexus.
- Climbing a step.