Os coxa

Medial view (deep surface), left side

Lateral view (superficial surface), left side

The os coxa is also known as the pelvic bone or innominate bone. It is actually three fused bones: the pubis, ilium, and ischium. At birth they are still three bones joined by cartilage and they fuse when the individual is about 16 to 18 years old. The pleural is os coxae. The ilium is the superior most of the three, the pubis is the most anterior, and the ischium is the most inferior.