Corpus: Iliac muscle

The iliacus muscle is a skeletal muscle that belongs to the inner hip muscles. It is functionally combined with the psoas major muscle to form the iliopsoas muscle.

The iliacus muscle originates from the iliac fossa and the joint capsule of the hip joint. Together with the psoas major muscle, it attaches to the lesser trochanter of the femur.

Both the iliacus and psoas major muscles run within a common fascia under the inguinal ligament through the muscular compartment to the thigh.

The iliacus muscle is innervated by branches of the femoral nerve (segments L3 to L4) and direct branches from the lumbar plexus.

The iliacus muscle works in conjunction with the psoas major muscle. In the hip joint, it flexes the thigh and supports its adduction. Depending on the initial position of the femur, it can also assist in both internal and external rotation.

When the legs are fixed, the iliacus muscle pulls the spine upwards or bends the trunk forward when tension is applied on both sides.