The clavicle is a long bone that is part of the shoulder. It connects the arm to the main part of the body. It is a support for the scapula bone and helps the arm to hang freely. This allows the arm to have a lot of movement. The clavicle is made from sponge-like bone, called cancellous bone, and is covered with a hard shell of bone. Most mammals and many other land vertebrates have clavicles.