THE SKULL THE CRANIUM 



163 



FIG. 108. 



large occipital plate and the small basilar process. Of these the 

 occipital plate (Fig. 108) is the broad, vertical, posterior part. It 

 lies behind the interparietal, and 

 extends transversely between the 

 posterior ends of the parietals and 

 the temporals, thus completing the 

 back of the skull, except at the 

 lower part, where a large occipital 

 foramen (foramen magnum) per- 

 mits the union of the brain with 

 the spinal cord. At right angles POSITION OF OCCIPITAL BONE . 



to the occipital plate, the long, 



narrow, tongue-shaped, horizontal portion, the basilar process or 

 basioccipital (Figs. 107, 109), projects forward to meet the posterior 



FIG. 109. 



With Interparietal. 



With Basisphenoid. 



Lambdoidal Ridge. 

 Supraoccipital. 



Upper Margin of Foramen 

 Magnum. 



Exoccipital. 

 Condyle. 



Basioccipital. 

 Anterior Condyloid Foramen. 



Jugular or Paroccipital Process. 

 Fossa for Auditory Bulla. 



OCCIPITAL BONE, SIDE VIEW. 



border of the basisphenoid. It lies between the temporal bones and 

 supports the posterior part of the brain. 



The upper part only of the occipital plate is free ; the rest is 

 covered by the heavy posterior cervical muscles. Very little, there- 

 fore, of the external surface of the occipital bone can be felt during 

 life. The basilar process is deeply placed above and in front of the 

 pharynx and the anterior cervical muscles attached to the head. 



The Occipital Plate is divided into three areas, corresponding to 

 the centres from which it is developed. The upper part is the supra- 

 occipital ; the lower parts on each side of the foramen magnum are the 



