THE FIFTH, TRIGEMINAL, OR TRIFAGIAL NERVE 989 



The ascending branches (rami orbitales} are two or three delicate filaments which 

 enter the orbit by the sphenomaxillary fissure, and supply the periosteum and the 

 nonstriated muscle parts of the Leva tor palpebrae or Superior tarsal muscle, 

 the Inferior tarsal muscle, and the Orbital muscle of Miiller. According to 

 Luschka, some filaments pass through foramina in the suture between the os 

 planum of the ethmoid and frontal bone to supply the mucous membrane of 

 the posterior ethmoidal and sphenoidal sinuses. 



The descending or palatine branches (tin. palatini) (Fig. 735) are distributed 

 to the roof of the mouth, the soft palate, tonsil, and lining membrane of the nose. 

 They are almost a direct continuation of the sphenopalatine branches -of the 

 superior maxillary nerve, and are three in number anterior, middle, and posterior. 



The anterior palatine nerve 1 (n. palatinus anterior} descends through the posterior 

 palatine canal, emerges upon the hard palate at the posterior palatine foramen, 

 and passes forward in a groove in the hard palate, nearly as far as the incisor 

 teeth. It supplies the gums, the mucous membrane, and glands of the hard palate, 

 and communicates in front with the termination of the nasopalatine nerve (see 

 below). While in the posterior palatine canal it gives off inferior nasal branches 

 (rami nasales posteriores inferiores}, which enter the nose through openings in 

 the palate bone and ramify over the turbinated bone and middle and inferior 

 meatuses; and, at its exit from the canal, a palatine branch is distributed to both 

 surfaces of the soft palate. 



The middle palatine nerve (n. palatinus medius} descends through one of the 

 accessory posterior palatine canals, distributing branches to the uvula, tonsil, 

 and soft palate. It is occasionally wanting. 



The posterior palatine nerve (n. palatinus posterior} descends with a minute 

 artery through the posterior palatine canal, and emerges by a separate opening 

 behind the posterior palatine foramen. It supplies the soft palate, tonsil, and 

 uvula. The middle and posterior palatine join with the tonsillar branches of 

 the glossopharyngeal to form a plexus around the tonsil (circulus tonsillaris). 



The internal branches are distributed to the septum and outer wall of the nasal 

 fossae. They are the superior nasal and the nasopalatine. 



The superior nasal branches (rami nasales posteriores superiores}, four or five 

 in number, enter the back part of the nasal fossa by the sphenopalatine foramen. 

 They supply the mucous membrane covering the superior and middle turbinated 

 processes, and that lining the posterior ethmoidal cells, a few being prolonged 

 to the upper and back part of the septum. 



The nasopalatine nerve (n. nasopalatinus} also enters the nasal fossa through 

 the sphenopalatine foramen; it passes inward across the roof of the nose, below 

 the orifice of the sphenoidal sinus, to reach the septum, and then runs obliquely 

 downward and forward along the lower part of the septum, to the anterior palatine 

 foramen, lying between the periosteum and mucous membrane. It descends 

 to the roof of the mouth through the anterior palatine'canal (^"735). The two 

 nerves are here contained in separate and distinct canals, situated in the inter- 

 maxillary suture, and termed the foramina of Scarpa, the left nerve being usually 

 anterior to the right one. In the mouth they become united, supply the mucous 

 membrane behind the incisor teeth, and join with the anterior palatine nerves. 

 The nasopalatine nerve furnishes a few small filaments to the mucous membrane 

 of the septum. 



Posterior Branch. The pharyngeal or pterygo palatine nerve (Fig. 735) is a small 

 branch arising from the back part of the sphenopalatine ganglion. It passes 

 through the pterygopalatine canal with the pterygopalatine artery, and is dis- 

 tributed to the mucous membrane of the upper part of the pharynx, behind the 

 Eustachian tube. 



1 Formerly called the great palatine nerve. 



