How is the arm held clear of the top of the thoracic cage?

The clavicle serves as an anterior base or strut to hold the arm away from the top of the thorax. The thoracic cage is formed by the vertebral column, ribs, and sternum and encloses the heart and lungs. In humans, the rib cage, also recognized as the thoracic cage is a bony and cartilaginous construction which environs the thoracic cavity and cares the pectoral girdle or shoulder girdle creating a core portion of the human skeleton.