plain bone of short length that serves as a strut between the scapula and the sternum
The clavicle, or collarbone, 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.
Clavicle is a formal scientific term. Normally we use the term collarbone, both in everyday speech and literary fiction.