The medial (situated near the midline) or sternal (situated near the sternum) end of the clavicle articulates with the sternum at the sternoclavicular joint (SC joint). The upper extremities join the axial skeleton (made up of 80 bones within the central core of the body) at the sternoclavicular joints. The lateral (toward the sides) or acromial end of the clavicle articulates with the acromion process at the acromioclavicular joint or AC joint. The clavicle and the scapula make up the shoulder girdle or pectoral girdle.