THE CRANIAL OR ENCEFHALIG NERVES. 713 



from the superior maxillary nerve at the orbital hiatus, from a trunk common 

 to_ it and the nasal and staphylin branches ; it passes into the palatine canal 

 with the palato-labial artery, which it follows to the foramen incisivum 

 where it stops. ' 



During its course in the palatine canal, this nerve throws off two or three 

 small filaments, which escape by particular foramina to the anterior part of 

 the soft palate— mediOTC ■palatine nerve. Frequently they arise from a common 

 trunk before the great palatine nerve enters its canal, and pass to their 

 destination by particular openings. For the remainder of its extent on the 

 roof of the palate, this nerve forms, around the artery it accompanies, a 

 plexiform network similar to that of the ganglionic nerves ; the filaments 

 escaping laterally from it are sent to the soft parts of the palate, as well as 

 to the gums. 



3. Staphylin ok Postkkiok Palatine Nerve (Fig. 148, 8). The 



filaments composing this nerve are very easily separated, and frequently 

 anastomose with those of the preceding nerve. They accompany the 

 palatine artery in the canal of that name, bend in front of the pterygoid 

 process to penetrate the soft palate between the glandular layer and the 

 tunica albuginea. They then become inflected backwards, and ramify 

 either in the mucous and glandular tissues of the velum pendulum, or the 

 palato-pharyngeal and circumflexus-palati muscles. This destination, 

 therefore, indicates in this nerve the presence of motor fibres ; we will see 

 hereafter whence they come. 



4. Nasal op. Sphbno-palatinb Nerve. — Springing from the same 

 trunk as the two preceding nerves, thicker than the staphylin, and nearly of 

 the same volume as the anterior palatine, the nasal nerve passes with- its 

 artery into the nasal or spheno-palatine foramen, to penetrate the cavity 

 of the nose, where it separates into two branches — external and internal, 

 which are distributed to the pituitary membrane. 



5. Dental Branches. — These are destined to the roots of the upper 

 teeth, and proceed from the superior maxillary nerve during its inter- 

 maxillary course ; some even arise before the entrance of that nerve into the 

 bony conduit, which it passes through to reach the face. These latter, 

 analogous to the posterior dental nerve of Man, enter the canal with the 

 parent branch, and throw their divisions into the roots of the last molar 

 tooth, and sometimes also into the second last. One portion of them 

 plunges directly into the maxillary protuberance, to be expended in t he 

 mucous membrane lining that protuberance, after furnishing some fila- 

 ments to the periosteum. 



Among the dental branches given off from the maxillary nerve during 

 its interosseous course, some pass to the molars, and others to the canine and 

 incisor teeth. The first, or middle dental nerves, separate in groups from 

 the maxillary trunk on its passage above the roots of the grinding-teeth ; 

 they penetrate these roots after a brief forward course, and give some thin 

 filaments to the membrane lining the maxillary sinuses. 



The second are only at first a single branch— the anterior dental nerve, 

 which rises from the maxillary trunk shortly before it leaves its bony canal. 

 After a somewhat long track in the substance of the maxillary bones, this 

 branch becomes expended in furnishing the ramuscules for the canine 

 tooth and the incisors ; it is always accompanied by a very slender arterial 



twisT 



6. Infba-orbital or Terminal Branches of the Superior Maxil- 

 lary' Neryb. These ramuscules spread on the side of the face in a magni- 



