Pectoral girdle

The pectoral girdle is the set of bones which connect the upper limb to the axial skeleton on each side. It consists of the clavicle and scapula in humans and, in those species with three bones in the pectoral girdle, the coracoid. Some mammalian species (e.g. dog and horse) have evolved to have only the scapula. In humans, the only joints between shoulder girdle and axial skeleton are the sternoclavicular joints on each side. No joint exists between each scapula and the thoracic cage, instead the muscular connection between the two permits relatively great mobility of the shoulder girdle in relation to the pelvic girdle. In those species having only the scapula, no joint exists between the forelimb and the thorax, the only attachment being muscular.

references:

http://en.wikipedia.org/wiki/Pectoral_girdle