i2o6 A MANUAL OF ANATOMY 



traverses the posterior palatine canal it gives off a posterior and 

 an external branch, which accompany corresponding nerves in the 

 posterior and external accessory palatine canals, and supply the 

 soft palate and tonsil. 



The Vidian artery passes backwards through the Vidian canal in 

 company with the Vidian nerve, and its branches are : (i) pharyngeal, 

 to the upper part of the pharynx ; (2) Eustachian, to the Eustachian 

 tube ; and (3) tympanic, to the tympanum. 



The pterygo-palatine artery, of small size, passes backwards 

 through the pterygo-palatine canal, in company with the pharyngeal 

 nerve, and is distributed to the upper part of the pharynx, the 

 Eustachian tube, and the mucous lining of the corresponding 

 sphenoidal air-sinus. 



The spheno-palatine artery enters the superior meatus of the 

 nasal fossa through the spheno-palatine foramen. Its branches 

 are distributed extensively on the outer wall of the nasal fossa, 

 and supply the mucous membrane of the antrum, ethmoidal cells, 

 and frontal air-sinus. One branch, called the naso-palatine artery, 

 or artery of the septum, descends upon the septum to the incisor 

 foramen, where it anastomoses with the ascending branch of the 

 descending palatine artery. 



Pterygoid Plexus of Veins. — ^This is a large plexus which surrounds 

 the external pterygoid muscle. Its tributaries correspond, for the 

 most part, to the branches of the internal maxillary artery, and 

 are chiefly as follows : the deep auricular, tympanic, two middle 

 meningeal, inferior dental, masseteric, pterygoid, deep temporal, 

 buccal, superior dental, infra-orbital, palp.tine, and spheno-palatine. 

 The blood is conveyed away from the plexus by two veins, namely, 

 the internal maxillary and the deep facial. 



The internal maxillary vein is a short vessel which issues from 

 the posterior part of the plexus, and accompanies the first part of 

 the internal maxillary artery. Opposite the neck of the inferior 

 maxilla it joins the superficial temporal vein within the parotid 

 gland to form the tempo ro-maxillary vein. 



The deep facial vein issues from the anterior part of the pterygoid 

 plexus, and, passing downwards and forwards, it emerges from 

 behind the mandibular ramus and masseter muscle, and joins the 

 facial vein on the buccinator muscle. The pterygoid plexus 

 establishes the following important connections superiorly : it com- 

 municates with the intracranial cavernous sinus by means of 

 emissary veins, which pass through the foramen ovale, foramen 

 Vesalii, and foramen lacerum medium ; and it communicates with 

 the inferior ophthalmic vein at the spheno-maxillary fissure. 



Internal Maxillary, Deep Facial, or Zygomatic Lymphatic Gland 

 {LymphoglandulcB faciales profundce). — These glands lie upon the 

 external pterygoid muscle. Their afferent vessels are derived from 

 (i) the zygomatic and temporal fossae; (2) the orbit; (3) the palatal 

 mucous membrane; (4) the nasal fossa, in part; (5) the cerebral dura 

 mater; and (6) the tympanic cavity. Their efferent vessels pass to 



