The ilium is the largest and most superior of the three bones composing the hip bone, forming the superior part of the acetabulum, and is characterized by defined bony landmarks including the iliac crest, the ala (wing), and the anterior superior, anterior inferior, posterior superior, and posterior inferior iliac spines. These landmarks, together with the gluteal lines (anterior, inferior, and posterior) on the lateral surface, define discrete attachment sites for musculature—most notably the gluteal muscles—illustrating the principle in osteology that bony surface features correspond functionally to sites of muscular or ligamentous attachment.
The ilium is the largest and most superior of the three bones composing the hip bone, forming the superior part of the acetabulum, and is characterized by defined bony landmarks including the iliac c…