The illustration shows the major bones in the skeleton of an adolescent. Bones highlighted include the skull and bones in the torso such as the clavicle, ribs, sternum, vertebrae, and sacrum. It also highlights the bones of the arms, including the humerus, ulna, and radius and the bones of the legs, including the femur, tibia, and fibula. Copyright 2013 American Society of Clinical Oncology. Robert Morreale/Visual Explanations, LLC.