The comprehensive term applied to the hard structures that support or protect the softer tissues of the body. Many animals are possessed of an exoskeleton, consisting of superficial plates of bone, horn, or the like; but in humans the skeleton is entirely an endoskeleton, covered everywhere by soft parts and consisting mainly of bones, but in places also of cartilage. The chief positions in which cartilage is found in place of bone are the larynx and the front of the chest. (For details of the skeleton, see BONE.)