174 HEAD AND NECK 



pterygoid muscles. The Deep Temporal Branches are two in 

 number anterior and posterior ; they pass upwards in fche 

 temporal fossa, between the bony wall of the cranium and the 

 temporal muscle. They supply twigs to the temporal muscle, 

 and they anastomose with the middle temporal artery. The 

 Buccinator Branch accompanies the buccinator nerve, and 

 is distributed to the buccinator muscle and the mucous 

 membrane of the cheek. It anastomoses with the external 

 maxillary (O.T. facial) artery. 



Arteria Alveolaris Superior Posterior. The posterior 

 superior alveolar branch from the third part of the internal 

 maxillary artery, descends upon the posterior aspect of the 

 maxilla, and sends branches through the alveolar canals of 

 the maxilla for the supply of the upper molar and praemolar 

 teeth (Fig. 63). Some small twigs go to the gum, and 

 others supply the lining membrane of the maxillary sinus. 



Plexus Pterygoideus et Vena Maxillaris Interna. The 

 veins of the infratemporal region are very numerous, but they 

 cannot be studied satisfactorily in an ordinary dissection. 

 They constitute a dense plexus, termed the pterygoid plexus, 

 around the external pterygoid muscle. Tributaries corre- 

 sponding to the branches of the internal maxillary artery open 

 into the network, whilst the blood is led away from its 

 posterior part by a short wide trunk, called the internal 

 maxillary vein. 1 That vessel accompanies the first part of 

 the internal maxillary artery into the parotid gland, where 

 it joins the posterior facial vein behind the neck of the 

 mandible. 



The pterygoid venous plexus is connected with the 

 cavernous sinus by an emissary vein. It communicates with 

 the inferior ophthalmic vein, through the inferior orbital fissure, 

 and with the anterior facial vein by an anastomosing channel, 

 called the deep facial vein, which descends across the external 

 surface of the buccinator muscle. 



Articulatio Mandibularis. Before the external pterygoid 

 muscle is thrown forwards, the mandibular joint must be 

 examined. It is a diarthrodial joint of the ginglymus type, 

 and its cavity is separated into an upper and a lower part 

 by an articular disc. In connection with it there are the 

 following ligaments : 



1 The internal maxillary vein may be replaced by two venae comites. 



