88 



A MANUAL OF ANATOMY 



triangular, errated impression, for the anteroinferior angle of the 

 parietal. 



The sphenoidal fissure, also called the foramen lacerum anterius 

 or orbitale, is situated between the great and small wings. It is 

 triangular, and its direction is inwards and downwards. It is 

 bounded above by the small wing, below by the internal border of 

 the great wing, and internally by the anterior part of the side of the 

 body, whilst externally it is closed by the frontal, or, it may be, the 

 meeting between the two wings. It leads from the middle cranial 

 fossa to the orbit, and transmits the following structures : the 

 third cranial nerve, the fourth, the three branches of the ophthal- 

 mic division of the fifth (namely, frontal, lachrymal, and nasal), and 

 the sixth cranial nerves, the sympathetic root of the ciliary ganglion, 



Posterior Clinoid Process 



Anterior Clinoid Process 



Post, or Sylvian Border 

 of Small Wing 



Dorsum Sellae 



I Back Part of Carotid Groove 



I I 



! 1 Sphenoidal Fissure 



Ext. Bord. of Great 

 Wing, for Squam. 

 Port, of Temporal 



Sup. Surf, of 

 Great Wing 



Spinous Process-' 



Lingula/ 



Vidian Canal y / 

 Scaphoid Fossa 

 Ext. Pterygoid Plate 



Groove for Chorda 

 Tjmpani Nerve 

 ^ ■ Pterygoid Tubercle 

 ^ Vaginal Process 



^ Rostrum 



^ Pterygoid Fossa 



Int. Pterygoid Plate ' 



Fig. S5- — The Sphenoid Bone (Posterior View) 



Pterygoid Notch 

 Hamular Process 



the superior and inferior ophthalmic veins, the orbital branch of 

 the middle meningeal artery, and a portion of the dura mater 

 to form the orbital periosteum. 



The pterygoid processes project downwards from the junction 

 of the body and great wings. Each is composed of two plates, 

 external and internal, united in front to form a thick round 

 border, except inferiorly, where they are separated by the 

 pterygoid notch, which receives the pyramidal process or tuber- 

 osity of the palate bone. At the upper end of the anterior 

 border a triangular surface opens out, which lies in the posterior 

 wall of the spheno-maxillary fossa, and presents the anterior orifice 

 Of the Vidian or pterygoid canal. Posteriorly the two plates diverge, 

 and enclose between them the pterygoid fossa, which contains 

 the internal pterygoid and tensor or circumflexus palati muscles. 



