The acromion process, is a small projection of the scapula that extends anteriorly from the spine of the scapula. serves as the point of attachment for the deltoid muscle, which is the major muscle that allows us to lift or abduct our arms. Related Theory The hip bone, or coxal bone, forms the pelvic girdle portion of the pelvis. The paired hip bones are the large, curved bones that form the lateral and anterior aspects of the pelvis. Each adult hip bone is formed by three separate bones that fuse together during the late teenage years. These bony components are the ilium, ischium, and pubis.