142 DISSECTION OF THE HEAD. 



Branches. The branch to the septum (fig. 33) divides into filaments 

 that ramify on the anterior part of that partition, and reach nearly to the 

 lower border. 



One or tico filaments are likewise furnished by the nerve to the mucous 

 membrane on the outer wall of the nasal fossa ; these extend as low as the 

 inferior spongy bone. 



TERMINAL BRANCHES OF THE INTERNAL MAXILLARY ARTERY. The 

 branches of the artery in the spheno-maxillary fossa, which have not been 

 examined, are the superior palatine, naso-palatine, pterygo-palatine, and 

 vidian. 



The superior or descending palatine is the largest branch, and accom- 

 panies the large palatine nerve through the canal, and along the roof of 

 the mouth ; it anastomoses behind the incisor teeth with its fellow, and 

 with a branch through the incisor foramen. This artery supplies offsets 

 to the soft palate and tonsil through the other palatine canals, and some 

 twigs are furnished to the lining membrane of the nose. In the roof of 

 the mouth the mucous membrane, glands, and gums, receive their vessels 

 from it. 



The nasal or spheno-palatine artery enters the nose through the spheno- 

 palatine foramen, and divides into branches : Some of these are distributed 

 on the spongy bones, and the outer wall of the nasal fossa, and supply otf- 

 sets to the posterior etbmoidal cells. One long branch, artery of the sep- 

 tum (art. naso. palatina) runs on the partition between the nasal fossa? to 

 the incisor foramen, through which it anastomoses with the superior pala- 

 tine in the roof of the mouth ; this branch accompanies the naso-palatine 

 nerve, and covers- the septum with numerous ramifications. 



The pterygo-palatine is a very small branch which, passing backwards 

 through the canal of the same name, is distributed to the lining membrane 

 of the pharynx. 



The vidian or pterygoid branch is contained in the vidian canal with 

 the nerve of the same name, and ends on the mucous membrane of the 

 Eustachian tube and the upper part of the pharynx. 



Some small nasal arteries are furnished to the roof of the nasal fossa 

 by the posterior ethmoidal branch of the ophthalmic (p. 56). Also the 

 anterior ethmoidal (internal nasal, p. 57), enters the cavity with the nasal 

 nerve, and ramifies in the lining membrane of the fore part of the nasal 

 chamber as low as the vestibule ; a branch passes to the face between the 

 os nasi and the cartilage, with its nerve. Other offsets from the facial 

 artery supply the part near the nostril. 



Veins. The veins accompanying the terminal branches of the internal 

 maxillary artery unite in the spheno-maxillary fossa in the alveolar 

 plexus. Into this plexus offsets are received from the pterygoid plexus 

 and the infraorbital vein ; and from the plexus a large trunk (anterior in- 

 ternal maxillary) is directed forwards below the malar bone to join the 

 facial vein (p. 40). Beneath the mucous membrane of the nose the veins 

 have a plexiform arrangement, as before said. 



FACIAL NERVE IN THE TEMPORAL BONE (fig. 35). This nerve winds 

 through the petrous part of the temporal bone ; and it is followed with 

 difficulty in consequence of the extreme density of the bone, and the ab- 

 sence of marks on the surface to indicate its position. To render this 

 dissection easier, the student should be provided with a temporal bone, in 

 which the course of the facial nerve and the cavity of the tympanum are 

 displayed. 



