Iliaci

Iliaci is the plural form of the anatomical term iliacus, referring to the iliacus muscles. These paired muscles are part of the hip flexor group and occupy the iliac fossa on the internal surface of the ilium.

Each iliacus muscle originates from the iliac fossa and iliac crest, with some fibers arising from adjacent ligaments at the pelvic brim. The muscle converges with the tendon of the psoas major to form the iliopsoas tendon, which inserts on the lesser trochanter of the femur. Through this connection, the iliaci participate in the broader action of the iliopsoas complex.

The iliaci are innervated primarily by the femoral nerve, receiving fibers from spinal levels L2 to L4. Blood supply is mainly via the iliolumbar artery, a branch of the internal iliac artery, with additional contributions from branches such as the deep circumflex iliac arteries.

Functions of the iliaci include flexion of the hip joint, contributing to anterior pelvic tilt when the thigh is fixed, and providing stability to the hip joint. They work in concert with the psoas major to facilitate rapid hip flexion and to support upright posture during activities such as walking or running. Clinically, tension or injury involving the iliopsoas complex, including the iliaci, can contribute to groin or hip pain and may be evaluated in the context of iliopsoas syndrome or tendinopathy.