The bone which runs from the upper end of the breastbone towards the tip of the shoulder, across the root of the neck. It supports the upper limb, keeps it out from the side, and gives breadth to the shoulders. The bone is shaped like an ‘f’ with two curves, which give it increased strength. It is, however, liable to be broken by falls on the hand or on the shoulder, and is the most frequently fractured bone in the body. (See BONE, DISORDERS OF.)