Iliacus is a fan shaped muscle that fills the iliac fossa. It looks like a triangular sheet muscular mass.
Origin of iliacus muscle:
Iliacus arises from the iliac fossa, which is present on the inner side of the hip bone. A part of the muscle also arises from the anterior inferior iliac spine.
Insertion of iliacus muscle:
The iliacus joins the psoas major muscle to form the iliopsoas. The common tendon is inserted into the lesser trochanter of femur. The fibers of the iliacus are inserted in front of those of psoas major and also extend more distally over the lesser trochanter.
Blood supply of iliacus muscle:
Iliacus receives its blood supply from the medial femoral circumflex artery and iliac branch of iliolumbar artery.
Nerve supply to iliacus muscle:
Iliacus is innervated by the femoral nerve, which is a branch of the lumbar plexus.
Actions of iliacus muscle:
The iliacus, as part of the iliopsoas, flexes the thigh on the trunk at the hip joint, or if the thigh is fixed, it flexes the trunk on the thigh. The origin and insertion of the iliacus muscle indicate that it acts exclusively on the hip joint.