3D Illustration Of Human Body Hip Bone Anatomy. The Hip Bone Os Coxa, In Nominate Bone, Pelvic Bone[1] Or Coal Bone Is A Large Flat Bone, Constricted In The Center And Expanded Above And Below. In Some Vertebrates Including Humans Before Puberty It Is Composed Of Three Parts: The Ilium, Ischium, And The Pubis.