134 



OSTEOLOGY. 



palatine fossse. It consists of a body with three pairs of expanded processes, 

 the great wings, the small wings, and the pterygoid processes. 



The corpus (body), more or less cubical in form, is hollow, and contains within 

 it the two large sphenoidal air sinuses. These are separated by a partition, which 



aiuditory tube 

 ^ Petrosal process 

 Pterygoid canal 



Superior orbital 

 fissure 



Lateral lamina of the 

 pterygoid process 



Medial lamina of the 

 pterygoid process 



Spina angularis 



\ Lingtitersph^noi d alls 

 Scaphoid fossa 



Pterygoid fossa 



Pterygoid notch 

 Hamulus of medial pterygoid lamina 



FIG. 144. THE SPHENOID SEEN FROM BEHIND. 



is usually deflected to one or other side of the median plane. Each sinus extends 

 laterally for a short distance into the root of the great wing, and downwards and 

 laterally towards the base of the pterygoid process of the same side. They com- 



Superior orbital 



fissure 

 Optic foramen / 



Temporal 

 surface 



Infra-temporal / _, 



surface Foramen 



rotundum 



Pterygoid canal 



Pterygoid notch 



Orbital surface 

 Infra- temporal crest 



Angular spine 

 Spheno-maxillary surface 



Lateral pterygoid lamina 



__ Hamulus of medial 

 pterygoid lamina 



FIG. 145. THE SPHENOID SEEN FROM THE FRONT. 



municate by apertures with the upper and posterior part of the nasal cavities. In the 

 adult the posterior aspect of the body displays a sawn surface due to its separation 

 from the basi-occipital, with which in the adult it is firmly ankylosed. The superior 

 surface, from the anterior angles of which the small wings arise, displays an appear- 

 ance comparable to that of an oriental saddle (sella turcica). Over its middle there 

 is a deep depression, the fossa hypophyseos, in which is lodged the hypophysis 

 (O.T. pituitary body). Behind, this is overhung by a sloping ridge, the dorsum sellse, 

 the posterior surface of which is inclined upwards, and is in continuation with 



