The ilium is a paired bone that forms the uppermost and largest part of the hip bone.



  • Arcuate line - a prominent bony ridge on the internal surface of the ilium separating the body from the wing, also forming the boundary between the false pelvis and true pelvis
  • Iliac crest - the superior border of the iliac wing that extends between two bony projections:
  • Anterior inferior iliac spine and posterior inferior iliac spine
  • Iliac fossa - a concavity forming the internal surface of the wing of the ilium
  • Sacropelvic surface, which features the:
    • Auricular surface - an ear-shaped surface within the sacropelvic surface of the ilium, which articulates with the sacrum
    • Iliac tuberosity - a roughened area behind and above the auricular surface
  • Gluteal surface, which presents three ridges: the anterior, posterior, and inferior gluteal lines