320 HEAD AND NECK 



lower aspect of the hard palate, towards the incisive foramen. 

 It supplies the gum, the mucous membrane, and the glands 

 of the vault of the mouth ; and, in the neighbourhood of the 

 incisive foramen, it communicates with the naso-palatine 

 nerve. As it passes down the pterygo- palatine canal the 

 posterior inferior nasal branches, which were enclosed in 

 its sheath, leave it and enter the nasal cavity (p. 316). 



Whilst tracing the anterior palatine nerve in the palate, 

 the dissector should note the numerous glands which are 

 placed under the mucous membrane of the vault of the 

 mouth, and the manner in which they indent the bone. 1 



Dissection. The dissector will experience some difficulty 

 in exposing the nerves in the pharyngeal and pterygoid canals, 

 which are very inaccessible. 



To open up the pharyngeal canal the sphenoidal process of 

 the palate bone must be cautiously removed with the bone forceps, 

 and then the dissector should proceed to open up the pterygoid 

 canal (O.T. Vidian), which traverses the root of the pterygoid 

 process. As the bone is very hard and brittle in this region, the 

 dissection must be effected very carefully. 



The nerve of the pharyngeal canal belongs to the posterior 

 superior nasal group (p. 318). 



Nervus Canalis Pterygoidei (O.T. Vidian}. The nerve 

 of the pterygoid canal is formed by a junction between the 

 greater superficial petrosal branch of the facial and the great 

 deep petrosal branch of the carotid plexus. It traverses the 

 pterygoid canal, and joins the posterior aspect of the spheno- 

 palatine ganglion, of which it may be considered to repre- 

 sent both the motor and sympathetic root. In the canal it 

 is invested by a strong fibrous envelope, and when that is 

 removed the nerve may sometimes be noticed to break up 

 into a fine plexus which surrounds the accompanying artery. 

 It has already been seen to give some fine filaments to the 

 muco-periosteum of the nose. 



Rami Orbitales. The orbital branches of the ganglion 

 are exceedingly minute ; they pass forwards, through the 

 inferior orbital fissure, to supply the periosteum of the orbit. 



Termination of Internal Maxillary Artery. The internal 



1 An equally good method of tracing the anterior palatine nerve is to 

 remove the palatal processes of the palate and maxilla with the bone 

 forceps, and then to display the nerve and artery on the upper surface of 

 the mucous membrane and glands. 



