The iliacus is a stout, fleshy muscle, extending from the under part of the ilium or haunch bone to the thigh.

Origin. - From the under surface of the ilium.

Insertion. - To the small internal trochanter on the inner surface of the femur by a tendon common to this muscle and the psoas magnus.

Action. - To flex the femur on the pelvis and rotate the femur outwards.