SKULL. The skull is divided into two parts, the cranium and the face. In human anatomy it is customary to de scribe the former as consisting of eight and the latter 14 bones; the eight cranial bones, which constitute the brain case, being the occipital, two parietal, frontal, two temporal sphenoid and ethmoid; while are found, but to those around the parietal bones special names are given e. g., interparietal or sagittal; occipito parietal or lambdoid; fronto-parietal or coronal; parieto-temporal or squamous. During adult life many of the sutures close by bony union and disappear, but the 14 facial bones, which surround the cavities of the mouth and nose and com plete the orbits or cavities for the eyes, are the two nasal, two superior maxil lary, two lachrymal, two malar, two palate, two inferior turbinated, vomer, and inferior maxillary. The bones of the ear, the teeth, and the Wormian bones are not included in this enumeration. The lower jaw articulates with the tem poral bones by means of a diarthrodia joint, but all the others are joined by sutures. On the base of the cranium the occipital and sphenoid bones articulate by means of a plate of cartilage (syn chondrosis) in young subjects; in adults this becomes bony union. Sutures are
named from the bones between which they both the age at which this occurs and the order of its occurrence are subject to variation. Wormian bones are irregular ossifications found in relation to the su tures of cranial bones, but these bones are seldom seen in relation to the bones of the face.
The fact that concussion of the brain scarcely ever proves fatal, unless there is also fracture of the skull, affords the most distinct evidence that the skull is constructed in such a manner that so long as it maintains its integrity it is able to protect its contents from serious lesion. There are two points in the archi tecture of the bones of the face which deserve special notice—viz. (1) the great strength of the nasal arch; and (2) the immobility of the upper jaw, which is fixed by three buttresses—the nasal, the zygomatic, and the pterygoid.