The Shoulder girdle is in essence a pelvis that has evolved to allow for the brachia apparatus, i,e,. mechanical specialization of the humerus and shoulder that facilitates the the needs of the pronated hand and opposable thumb. Freed from it's primary purpose of translocation and isonomic channeling (dispersion of gravitational force) which defines the structure of the pelvis , the Sacrum ,Ilium and Ischia have now separated and the scapula takes shape- becoming the Ischia and Ilium of the shoulder. These free floating "pelvic halves"allow for a greater range of movement than a fixed pelvis could ever allow..Clearly it is evident that he pubic bone of the pelvis is analogous to the clavicle of the shoulder girdle. With a bit of imagination it can also be observed that the Coracoid Process of the Scapula is analogous to the Pubic Bone of the Pelvis.