Final answer:
The os coxae consists of the ilium, ischium, and pubis bones, which fuse together to form the hip bone.
Step-by-step explanation:
The os coxae consists of three bones: the ilium, ischium, and pubis. These bones fuse together during the late teenage years to form the hip bone. The ilium forms the large, fan-like superior region of the hip bone. The ischium forms the posteroinferior region and supports the body when sitting. The pubis forms the anterior portion and curves medially to join with the pubis of the opposite hip bone at the pubic symphysis.