Iliacus is one of the muscles of the posterior abdominal wall. It originates from the superior part of the iliac fossa within the abdomen. Its fibres pass inferiorly and medially beneath the inguinal ligament. Some fibres attach to the psoas tendon; the combined entity is termed the iliopsoas muscle. Iliacus inserts into the inferior part of the lesser trochanter of the femur.
It is innervated by the femoral nerve in the abdomen (L2,L3).
Iliacus acts to:
- flex the thigh at the hip joint
- medially rotate the thigh