Iliac fascia

The iliac fascia is a fibrous sheet that covers the ventral surface of the iliac, major psoas, and minor psoas muscles. It forms a sheath that separates these muscles from the peritoneum and abdominal viscera. It extends from the lumbocostal arch of the diaphragm to the iliac region, where it attaches to the inguinal arch. It helps maintain the position and curvature of the lumbosacral muscles during contraction, a role particularly important in large ungulates.