777 



MAXILLAEY NEKVE. 



(4) The infra-orbital nerve, is the terminal branch of the maxillary nerve, which 

 enters the orbit through the inferior orbital fissure and traverses the infra-orbital 

 canal to reach the face. 



In the infra-orbital canal the infra-orbital nerve supplies one and sometimes 

 two branches to the teeth the middle and anterior superior alveolar nerves (ramus 

 alveolaris superior medius et rami alveolares superiores anteriores). The former may be 

 only a secondary branch of one of the latter nerves, or it may arise independently 

 from the infra-orbital nerve. However formed, the nerves descend in bony canals 

 in the wall of the maxillary sinus (to the lining of which branches are given), and 

 reach the alveolar arch, where they form minute plex'uses and supply the teeth 

 (joining posteriorly with the branches of the posterior superior alveolar nerves). 

 The anterior superior alveolar nerve supplies the incisor and canine teeth; the 

 middle superior alveolar nerve supplies the premolar teeth. 



After emerging on the face from the infra-orbital foramen, the infra-orbital 

 nerve divides into a number of radiating branches arranged in three sets (a) 



Zygomatic branch at inferior orbital fissure 



Maxillary nerve at foramen 

 rotundum 



jfra-orbital nerve appearing 

 the face at the infra-orbital 

 foramen 



Middle and anterior/ 

 alveolar branches \ 



Spheno-palatine ganglion and nerves 

 v - Palatine branches 

 Posterior superior alveolar nerve 



FIG. 654. COURSE -AND BRANCHES OF THE MAXILLARY NERVE. 



inferior palpebral (rami palpebrales inferiores), for the lower eyelid ; (&) external nasal 

 (rami nasales externi), for the skin of the side of the nose ; and (c) superior labial 

 (rami labiales superiores), for the cheek and upper lip. These branches form com- 

 munications with the zygomatic branches of the facial nerve, and' give rise to the 

 infra-orbital plexus (Fig. 657, p. 783). 



Ganglion Spheno-palatinum. The spheno - palatine ganglion occupies the 

 upper part of the pterygo- palatine fossa. It is a small reddish-gray ganglion, 

 suspended from the maxillary nerve by the two spheno-palatine branches which 

 constitute its sensory roots. The motor and sympathetic roots of the ganglion are 

 derived from the nerve of the pterygoid canal. This nerve is formed in the cranial 

 cavity, upon the cartilage filling up the foramen lacerum, by the union of the 

 greater superficial petrosal nerve from the genicular ganglion of the facial nerve 

 (emerging from the temporal bone through the hiatus canalis facialis) with the 

 deep petrosal nerve, a branch of the sympathetic plexus on the internal carotid 

 artery. The nerve of the pterygoid canal passes through the pterygoid canal 

 to the pterygo-palatine fossa, where it joins the spheno-palatine ganglion. 



