THE TRIGEMINAL NERVE. 



1 241 



Branches. — The branches of distribution of the spheno-palatine ganghon are 

 conveniently grouped into four sets : (i) the ascending, (2) the descending , (3) the 

 inter7ial znd (4) the: posterior. 



1. The ascending or orbital branches (rr. orbitales) (Fig. 1059) are two or 

 three tiny filaments, which pass into the orbit through the spheno-maxillary fissure and, 

 after traversing the posterior ethmoidal canal or a small special aperture, are distrib- 

 uted to the sphenoidal and posterior ethmoidal air-cells and the periosteum of the orbit. 



2. The descending branches (nn. palatini) (Fig. 1059) are three : {a) the 

 large posterior palatine, (d) the small posterior palatine, and (r) the accessory pos- 

 terior palatine 7ierves. 



a. The large posterior palatine nerve (n. palatinus anterior) leaves the spheno-maxillary fossa 

 by means of the large posterior palatine canal, through which it descends to the inferior surface 

 of the hard palate. While in the canal it gives off one or two posterior inferior nasal branches 



Fig. 1061. 



Cavernous plexus and 

 int. carotid artery 



Nasal nerve 



Nasal nerve, 

 ext. branch' 



Post. inf. nasal 



brs. of larije. 



posterior palatine 



nerve 



il 



Large, small and 



accessory poste-' 



rior palatine 



nerves 



Naso-palatine 



nerve. 



^ termination 



Great superficial 

 petrosal nerve 



Great deep petrosal 

 nerve from carotid 

 plexus 



Otic ganglion 



Cartilage of Eustachian 

 tube, cut 



Int. br. of ascending 

 ramus sup. cerv. gang!. 

 Ext. br. of as-ending 



ramus of sup. cerv 



ganglion 



Sup. cerv. ganglion 

 of sympathetic 



Int. carotid artery 



Uvula 



Superior constrictor 

 Levator palati 



Tensor palati, cut above 



Dissection showing spheno-palatine and otic ganglia viewed from within. 



(rr. nasales posteriores inferiores) , which, escaping through small apertures in the perpendicular 

 plate of the palate bone, enter the nasal fossa and supply the mucous membrane of all but the 

 anterior portion of the inferior turbinate bone and the adjoining portions of the middle and infe- 

 rior nasal meatuses. Emerging from its canal the main nerve passes forward in a groove on the 

 inferior aspect of the hard palate and inosculates with the terminal filaments of the naso-palatine 

 nerve. It supplies the hard palate and its mucous membrane, as well as the inner side of the gum. 



b. The small posterior palatine nerve (n. palatinus posterior) descends in the small pos- 

 terior palatine canal. It supplies sensory filaments to the mucous membrane of the soft palate 

 and the tonsil and motor ones to the levator palati and azygos uvulae muscles. 



c. The accessory posterior palatine nerves (nn. palatinus medius) are one or more small 

 filaments which pass through the accessory posterior palatine canals and supply the mucous 

 membrane of the soft palate and tonsil. 



3. The internal branches (rr. nasales posteriores superiores) (Fig. 1059) pass 

 from the spheno-maxillary into the nasal fossa through the spheno-palatine foramen. 

 They are : (a) the posterior superior nasal and (b) the naso-palatine nerve. 



