632 



DISSECTION OF DEEP VESSELS AND NERVES OF NECK. 



Its upper 



and lower 

 ganglion. 



In the neck 



courses to 

 the tongue. 



Branches 

 to join 



with others, 

 viz., 



sympathetic 

 and vagus, 



facial and 

 sympa- 

 thetic. 



Distributed 

 to 



pharynx, 



stylo- 

 pharyngeus, 



tonsil, 



and tongue. 



Vagus nerve 



in jugular 

 foramen, 



and in the 

 neck, 



The jugular ganglion (fig. 226, 4 ) is very small, and is situate at the 

 upper end of the osseous groove containing the nerve. It includes 

 only the outer fibres of the nerve, and is not always to be recognised. 

 The petrosal ganglion ( 5 ) is much larger, and encloses all the fibrils 

 of the nerve. Ovalish in form, it is placed in a hollow in the 

 posterior border of the temporal bone ; and from it spring the 

 branches that unite the glosso-pharyngeal with other nerves. 



After the nerve has quitted the foramen, it comes forwards 

 between the jugular vein and the carotid artery (fig. 225, *), and 

 descends over the artery until it reaches the hinder border of the 

 stylo-pharyngeus muscle. Then curving forwards, it becomes almost 

 transverse in direction, crosses the stylo-pharyngeus, and finally 

 passes beneath the hyo-glossus muscle, where it ends in branches to 

 the tongue. 



The branches of the glosso-pharyngeal may be classed into those 

 connecting it with other nerves at the base of the skull, and those 

 distributed in the neck. 



The connecting brandies arise from the petrosal ganglion ; and in this 

 set is the tympanic nerve. 



* 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, another to the upper 

 ganglion of this nerve and a twig to join the branch of the facial to 

 the posterior belly of the digastric. 



* The tympanic branch (nerve of Jacobson ; fig. 226, 6 ) enters the 

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

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

 tympanum : its distribution is given with the anatomy of the 

 middle ear (page 812). 



Branches for distribution. In the neck the branches are furnished 

 chiefly to the pharynx and the tongue. 



a. Pharyngeal branches. Two or three branches, arising from the 

 glosso-pharyngeal nerve as it lies over the carotid artery, descend 

 to join the pharyngeal branch of the vagus and take part in the 

 formation of the pharyiigeal plexus ; and one or two smaller twigs 

 penetrate the superior constrictor muscle. 



b. A muscular branch enters the stylo-pharyngeus while the nerve 

 is in contact with the muscle. 



c. 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. 



d. Lingual branches. The terminal branches of the nerve supply 

 the hinder part of the tongue, in connection with which they are 

 described (page 688). 



The PNEUMO-GASTRIC or VAGUS NERVE (figs. 225, 3 and 226, 2 ) is the 

 largest of the cranial nerves in the neck, and escapes through the jugu- 

 lar foramen in the same sheath of dura mater as the spimil accessory. 

 In the foramen it has a distinct ganglion (gang, of the root), to which 

 the smaller part of the spinal accessory nerve is connected. 



When the nerve has left the foramen, it receives the small part of 



