2oS 



MAMMALIAN ANATOMY 



the olivary process and the dorsum sellae is known as the sella turcica, 1 

 or, since it lodges the pituitary process of the brain, as the pituitary 2 

 fossa. It is usually longer than wide, and its lateral boundaries are 

 marked to a greater or less degree by faint ridges, prolongations 

 backward of the lateral margins of the anterior and posterior walls of 

 the fossa ; at times, but rarely, these ridges are elevated near the front 

 into middle clinoid processes. In the pituitary fossa, in the front 

 part of its middle line, is a small pituitary foramen which pierces the 

 bone and gives exit to a vein ; smaller secondary foramina leading into 

 the substance of the bone are also sometimes observed. The upper 

 margin of the dorsum sellse is swollen and emarginate ; the upper 



FIG. 187. 



With Presphenoid. 



With Palatine. 



Orbital Surface of Pterygoid Process 

 External Pterygoid Process. 



Groove for Vidian Nerve. 



Foramen Kotundum. 

 Foramen Ovale. 



Groove for Cavernous Sinus. I 



Large Notch. 



Parietal Angle. 



With Presphenoid. 

 Sella Turcica. 



Small Notch. 

 Lingula. 



With Tentorium. 

 With Petrous. 



Petrosal Process. 

 POSTERIOR SPHENOID. SUPERIOR SURFACE. 



angles are more or less prominent, and are known as the posterior 

 clinoid processes. The dura mater of the brain, stretched from the 

 anterior to the posterior clinoid processes, defines and deepens the sella 

 turcica. The posterior surface of the dorsum sella?, known as the 

 clivus, 3 faces upward and backward. It is wider below than above, is 

 slightly concave in both directions, and is pierced by venous foramina. 

 It is crossed by a venous sinus and an artery. The sides are directed 

 downward, outward, and backward. They are usually notched at 

 their bases for the passage of the sixth pair of cranial nerves. The 

 lower margin of the dorsum sellse is also the posterior margin of the 

 body of the bone, and comprises the middle third of the entire pos- 

 terior border. It is rough and irregular, articulating with the front of 



1 A Turkish saddle. 2 From pituita, slime. 3 A slope. 



