THE SKULL. 67 



canals for the transmission of meningeal arteries to the 

 brain ; it is also traversed horizontally by the large 

 petrosal nerve, which enters the Vidian canal at the base 

 of the pterygoid process. The interval between the 

 petrous and squamous portions of the temporal is occu- 

 pied by the great wing of the sphenoid, which here pre- 

 sents two foramina, the foramen spinosum and the 

 foramen ovale. The latter is placed external to the base 

 of the pterygoid process, and transmits the third division 

 of the fifth pair of nerves. External and posterior to the 

 foramen ovale is the foramen spinosum, in the spinous 

 process of the great wing of the sphenoid; it trans- 

 mits the middle meningeal artery. In front of these 

 foramina the base is concave from side to side, and forms 

 the roof of the zygomatic fossa. External to the petrous 

 portion of the temporal is the glenoid fossa for articula- 

 tion with the condyle of the inferior maxillary bone. It 

 is limited posteriorly by the post-glenoid tubercle (the 

 second root of the zygoma), the wall of the meatus au- 

 ditorius extemus, and the vaginal process; anteriorly, 

 by the tubercle of the zygoma and the eminentia articu- 

 laris. Its axis is directed outward and somewhat forward. 

 The plane of the cranial portion of the base is directed 

 forward and upward. The facial portion of the base is 

 anterior to a line drawn through the tubercles of the 

 zygoma. " It drops abruptly from the anterior part of the 

 cranial portion of the base, its plane being directed 

 nearly horizontal, and, if continued backward, would 

 strike the posterior margin of the foramen magnum. 

 The facial portion of the base is formed behind by the 

 pterygoid processes, between which are the posterior 

 nasal openings, separated by the vomer. Projecting 

 posteriorly, in the middle line, is the posterior nasal spine, 

 which gives attachment to the uvula. 



