04 DISSECTION OF THE PTERYGOID REGION. 



maxillary trunk, and accompanying the gustatory nerve, ends in the cheek 

 and the mucous membrane of the mouth. 



The branches from the second part of the artery, viz., whilst it is between 

 the temporalis and pterygoideus externus are distributed to the temporal, 

 masseteric, buccal, and pterygoid muscles. 



The deep temporal arteries are two in number (anterior and posterior) ; 

 and each occupies the part of the temporal fossa indicated by its name. 

 They ascend beneath the temporal muscle, and anastomose with the super- 

 ficial temporal artery: the anterior communicates, through the malar bone, 

 witli branches of the lachrymal artery. 



When the parent trunk has the unusual position beneath the pterygoid, 

 the anterior branch lies under that muscle, instead of over it. 



The masseteric artery is directed outwards with the nerve of the same 

 name behind the tendon of the temporal muscle ; and passing through the 

 sigmoid notch, enters the under surface of the masseter muscle. Its 

 branches anastamose with the other offsets to the muscle from the external 

 carotid trunk. 



The buccal branch quits the artery near the upper jaw, and in the un- 

 usual position of the artery it may perforate the fibres of the pterygoid ; 

 it descends beneath the coronoid process with its companion nerve, and is 

 distributed to the buccinator muscle, the cheek, and the side of the face, 

 joining the branches of the facial artery. 



The pterygoid branches are uncertain in their position; whether derived 

 from the trunk or some of the branches of the internal maxillary, they 

 enter both pterygoid muscles. 



Of the branches that arise from the artery when it enters the spheno- 

 maxillary fossa, only one, the superior dental, will be now described. The 

 remainder will be examined with the superior maxillary nerve and MeckeFs 

 ganglion ; they are infraerbital (p. 105), superior palatine, naso-palatine, 

 vidian, and pterygo-palatine (SECTION 14). 



The superior or posterior dental branch takes origin near the top of the 

 upper maxilla, and descends with a tortuous course on the outer surface of 

 that bone, along with a small branch of the superior maxillary nerve. It 

 sends twigs into the foramina in the bone, and supplies the upper molar 

 and bicuspid teeth ; but some external offsets are furnished to the gums. 

 A few branches reach the lining membrane of the antrum. 



The INTERNAL MAXILLARY VEIN receive the offsets accompanying the 

 branches of the artery in the first two parts of its course : these veins form a 

 plexus pterygoid, between the two pterygoid muscles, and in part be- 

 tween the temporal and external pterygoid muscles. This anastomosis 

 communicates with the alveolar plexus ; with the facial vein by a large 

 branch (anterior internal maxillary) ; and with the cavernous sinus in the 

 interior of the skull, by veinules that pass through the base of the cranium. 



Escaping from the plexus, the vein accompanies the artery to the paro- 

 tid gland, and there joins the superficial temporal vein, the union of the 

 two giving rise to the external jugular. Sometimes this common vessel 

 enters the internal jugular vein (p. 42). 



The INFERIOR MAXILLARY NERVE (fig. 21) is the largest of the three 

 trunks arising from the Gasserian ganglion (p. 32). It leaves the skull 

 by the foramen ovale in the sphenoid bone, and divides beneath the ex- 

 ternal pterygoid muscle into two chief pieces, viz., an anterior, small, moto- 

 sensory part ; and a large, posterior, chiefly sensory portion. 



