164 SKELETON. 



terior orifices of the nostrils, separated from each other by the 

 vomer. On each side are the pterygoid processes of the sphe- 

 noid bone, and above is its body. The pterygoid fossa, formed 

 between the external and internal process, and the long unci- 

 form termination of the latter with the broader and shorter ter- 

 mination of the former, will also be observed. 



The Occipital region of the base of the head, placed imme- 

 diately behind the other, may be considered to include the mas- 

 toid processes, and the foramen magnum occipitis, and to be 

 bounded behind by the tuber of the occiput and its superior 

 transverse ridges. Its marks have been sufficiently dwelt upon, 

 in the description of the os occipitis. 



The third oval will be described in detail in a short time. 



On the side of the head, where we consider the triangular 

 region to exist, the arch formed by the malar bone and the zy- 

 gomatic process of the temporal, forms a very conspicuous 

 feature. The anterior abutment of this arch is formed by the 

 greater part of the malar bone, and a considerable portion of 

 the malar process of the superior maxillary. The posterior 

 abutment is formed by the root of the zygomatic process of the 

 temporal bone. Its superior margin is thin, for the insertion 

 of the temporal aponeurosis : the inferior margin is thick, and 

 is divided, by a projection in its middle, into an anterior and a 

 posterior surface, marking the origins of the two portions of the 

 masseter muscle. There is a very considerable vacancy be- 

 tween the zygoma and the side of the head, occupied by the 

 coronoid process of the lower jaw, the temporal and the exter- 

 nal pterygoid muscles. The coronoid process is just within 

 the zygomatic arch, and the tip rises three or four lines above 

 its inferior margin. 



The large depression within the zygoma is the temporal fossa. 

 All that portion of the side of the head beneath the ridge lead- 

 ing from the external angular process of the os frontis, and run- 

 ning along the surface of the parietal bone, is tributary to the 

 temporal fossa. The bones, therefore, which form it, are the 

 frontal, the parietal, the temporal, the great wing and the ex- 

 ternal pterygoid process of the sphenoid bone, and the posterior 

 face of the superior maxillary and malar bones. The arrange- 



