Fig. 325—The human skeleton. From the right.
Fig. 326—The human skeleton. Front.
Fig. 327—The human vertebral column (standing upright, from the right side). (From H. Meyer.)
Fig. 328—A piece of the axial rod (chorda dorsalis), from a sheep embryo. a cuticular sheath, b cells. (From Kölliker.)
In order to get a clear idea of the chief features of the development of the human skeleton, we must first examine its composition in the adult frame (Fig. 325, the human skeleton seen from the right; Fig. 326, front view of the whole skeleton). As in other mammals, we distinguish first between the axial or dorsal skeleton and the skeleton of the limbs. The axial skeleton consists of the vertebral column (the skeleton of the trunk) and the skull (skeleton of the head); the latter is a peculiarly modified part of the former. As appendages of the vertebral column we have the ribs, and of the skull we have the hyoid bone, the lower jaw, and the other products of the gill-arches.