THE SKULL. 



57 



vical and lumbar regions, where it is shallow, and by the lamince and transverse 

 processes in the dorsal region, where it is deep and broad. In the recent state, 

 these grooves lodge the deep muscles of the back. External to the vertebral 

 grooves are the articular processes, and still more externally the transverse pro- 

 cesses. In the dorsal region, the latter processes stand backwards, on a place con- 

 siderably posterior to the same processes in the cervical and lumbar regions. In 

 the cervical region, the transverse processes are placed in front of the articular 

 processes, and between the intervertebral foramina. In the lumbar, they are placed 

 also in front of the articular process, but behind the intervertebral foramina. In 

 the dorsal region, they are posterior both to the articular processes and foramina. 

 The lateral surfaces are separated from the posterior by the articular processes 

 in the cervical and lumbar regions, and by the transverse processes in the dorsal. 

 These surfaces present in front the sides of the bodies of the vertebra?, marked in 

 the dorsal region by the facets for articulation with the heads of the ribs. More 

 posteriorly are the intervertebral foramina, formed by the juxtaposition of the inter- 

 vertebral notches, oval in shape, smallest in the cervical and upper part of the dorsal 

 regions, and gradually increasing in size to the last lumbar. They are situated 

 between the transverse processes in the neck, and in front of them in the back and 

 loins, and transmit the spinal nerves. The base of the vertebral column is formed 

 by the under surface of the body of the fifth lumbar vertebra; and the summit by 

 the upper surface of the atlas. The vertebral canal follows the different curves 

 of the spine ; it is largest in those regions in which the spine enjoys the greatest 

 freedom of movement, as in the neck and loins, where it is wide and triangular ; 

 and narrow and rounded in the back, where motion is more limited. 



Cranium, 8 bones. 



THE SKULL. 



The Skull, or superior expansion of the vertebral column, is composed of four 

 vertebrae, the elementary parts of which are specially modified in form and size, 

 and almost immovably connected, for the reception of the brain, and special 

 organs of the senses. These vertebrae are the occipital, parietal, frontal, and nasal. 

 Descriptive anatomists, however, divide the skull into two parts, the Cranium and 

 the Face. The Cranium (xpdvos, a helmet) is composed of eight bones: viz., the 

 occipital, two parietal, frontal, two temporal, sphenoid, and ethmoid. The face is 

 composed of fourteen bones: viz., the two nasal, (wo superior maxillary, two lachry- 

 mal, two malar, two palate, two inferior turbinated, vomer, inferior maxillary. The 

 ossicula auditus, the teeth, and Wormian bones, are not included in this enumeration. 



Occipital. 



Two Parietal. 



Frontal. 



Two Temporal. 



Sphenoid. 



Ethmoid. 

 Skull, 22 bones. Two Nasal. 



Two Superior Maxillary. 



Two Lachrymal. 



Two Malar. 



Two Palate. 



Two Inferior Turbinated. 



Vomer. 



Inferior Maxillary. 



BONES OF THE CRANIUM. 

 THE OCCIPITAL BONE. 



The Occipital Bone (fig. 22) is situated at the back part and base of the cranium, 

 is trapezoid in form, curved upon itself, and presents for examination two sur- 

 faces, four borders, and four angles. 



Face, 14 bones. 



