The collarbone is a doubly curved bone that connects the arm to the body (trunk). Located directly above the first rib it acts as a strut to keep the scapula in place so that the arm can hang freely. Medially, it articulates with the manubrium of the sternum (breast-bone) at the sternoclavicular joint.he clavicle is the only long bone in the body that lies horizontally. Together with the shoulder blade it makes up the shoulder girdle. It is palpable in all people; in people who have less fat in this region, the location of the bone is clearly visible, as it creates a bulge in the skin.