112 DISSECTION OF THE NEOK. 



* A filament ascends from the sympathetic nerve in the neck to join the 

 petrosal ganglion. Sometimes there is an offset from the ganglion to the 

 auricular branch of the vagus, as well as to the upper ganglion of this 

 nerve. 



* The tympanic branch (fig. 26, *) (nerve of Jacobson) enters the 

 aperture in the ridge of bone between the jugular and the carotid foramen, 

 and ascends by a special canal to the inner wall of the tympanum, where 

 it ends in branches : its distribution is given with the tympanum of the 

 ear. 



a. Bandies for Distribution. In the neck the branches are furnished 

 chiefly to the pharynx and the tongue. 



b. Carotid branches surround the internal artery of that name, and 

 communicate with the pharyngeal branch of the vagus, and the sympa- 

 thetic nerve. 



c. Some muscular branches enter the stylo-pharyngeus, whilst the nerve 

 is in contact with it. 



d. Branches to the pharynx form the pharyngeal plexus by uniting with 

 nerves from the sympathetic and vagus. 



e. The tonsillitic branches supply the tonsil and the arches of the soft 

 palate. On the former they end in a kind of plexus circulus tonsillaris. 



/'. Lingual branches. The terminal branches of the nerve supply the 

 root and posterior part of the tongue, as well as the lateral surface. The 

 distribution of these is described with the tongue (SECTION 15). 



The PNEUMOGASTRIC NERVE (fig. 26, 2 ) (vagus nerve) is the largest of 

 the cranial nerves in the neck, and escapes through the jugular foramen 



1. Glosso-pharyngenl trunk. 



2. Vagus. 



3. Spiual accessory. 



4. Jugular gantrlion. 

 6. Petrosal ganglion. 



6. Jacobsou's nerve. 



7. Auricular branch. 



8. Koot ganglion of vagus. 



9. Trunk ganglion of vagus. 



10. Branch joining the petrosal and upper 



ganglion of the vagus. 



11. Small part of spinal accessory. 



12. Chief part of spiual accessory. 



13. Pharyngeal branch of vagus. 



14. Superior laryugeal branch of vagus. 



DIAGRAM OF THE EIGHTH NERVE. 



in the same sheath of dura mater as the spinal accessory. In the aperture 

 of exit it has a distinct ganglion (gang, of the root), to which the smaller 

 part of the spinal accessory nerve is connected. 



