THE CRANIAL OR ENCEPHALIC NERVES. 817 



In addition to wliich are desciribed : 



6. The infra-orbital, or f/>rminal branchfis of the superior maxillary nerve. 



1. Orbital Branch (Fij?. 450, 13).— This ramusculc arises in the interior of 

 the supra-sphenoidal canal, and enters the ocular sheath with the divisions of 

 the ophthalmic branch. It almost immediately breaks up into two or three 

 very slender filaments, which ascend to the temporal aut;le of the eye, passing,' 

 between the fibrous Huin<4 of the orbit and the outer surface of the motor 

 muscles of the eye, and are distributed to the eyelids and neighbouring 

 integuments. 



2. Great or Anterior Palatine Nerve (or Palato-maxillary) (Fig. 

 215, 3). — It arises from the superior maxiUary nerve at the orbital hiatus, from 

 a trunk common to it and the nasal and staphyline 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 — median palatine nei've. Frcijuently they arise from a common trunk 

 before the palato-maxillary nerve enters its canal, and pass to their destination 

 by particular openings. For the remainder of its extent on the roof of th« 

 palate, this nerve forms, around the arteries 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. Staphyline or Posterior Palatine Nerve (Fig. 215, 8). — The fila- 

 ments 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 

 shall see hereafter whence they come. 



4. Nasal or Spheno-palatine Nerve. — Springing from the same trunk 

 as the two preceding nerves, thicker than the staphyline, 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 intra-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 posteiior 

 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 protu- 

 berance, to be expended in the mucous membrane lining it, after furnishing 

 some filaments 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 »i»/v^s — separate in groups from the maxillary 

 trunk on its passage above the roots of the molar teeth ; they penetrate these 



