A horizontal bone above the first rib that makes up the front part of the shoulder: The collarbone, also called the "clavicle", links the sternum, or breastbone, with the scapula, a triangular bone in the back of the shoulder.

The collar bone ends at the sternum, forming one side of the sternoclavicular joint; where it ends at the shoulder, there forming one side of the acromioclavicular joint.