260 



MAMMALIAN ANATOMY 



continuous with the orbital surface of the vertical plate of the palatine. 

 Behind this orbital surface, the upper surface of the pterygoid process 

 on the outer side forms the floor of the sphenoidal fissure. It is faintly 

 concave from side to side and nearly flat or gently convex from before 

 backward, and faces upward. Near its inner side is a well-defined 

 longitudinal groove which terminates posteriorly in a foramen, the 

 anterior opening of the Vidian canal. The groove may be partially 

 converted into a canal situated on the inside of the sphenoidal fissure. 



On each side of the sella is a faintly marked longitudinal depres- 

 sion for ik&* cavernous sinus ; this depression ends behind at the 

 angle of the notch for the temporal bone in a groove for the carotid 

 artery, arid is overlapped on the outside by a ridge on the lingula. 

 Lateral to this depression the surface is flattened and supports the 



FIG. 188. 



Ascending Process. With Parietal. 



i V'ith Frontal. 



With Squamosal of Temporal. 



With Parietal and Temporal. 

 Root of Tentorium. 

 Groove for Vessels and Nerve*. 



Foramen With Foramen 

 Ovale. Basi- Rotund inn. 

 sphenoid. 



With Orbitosphenoid. [Sphenoidal Fissure. 

 Notch forming with Orbitosphenoid the 

 With Presphenoid. 



~~ Middle Pterygoid Fossa. 



Hamular Process of Internal Pterygoid 

 Process. 



LEFT ALISPHENO1D, INNER ASPECT. 



Gasserian ganglion. It passes in front into the floor of the sphenoidal 

 fissure ; at the side it is continued under the sharp, overhanging, inner 

 border of the elevated portion of the general upper surface and between 

 vertical partitions, as the floor of the foramen rotundum and the fora- 

 men ovale. Behind these foramina it curves upward and forms under 

 the edge of the tentorium a fossa for the back of the ganglion. 



The foramen rotundum, or round foramen, lies next to the sphe- 

 noidal fissure, and pierces the bone obliquely, passing forward, outward, 

 and slightly downward. At the back of its inner wall is a small 

 foramen, which appears to be constant and leads into the interior of 

 the bone. 



The foramen ovale, or oval foramen, is a little larger or more oval 



