PNEUMOGASTRIC NERVE. 473 



branches which it afterwards sends off, go to the neck, to the 

 viscera of the thorax, and to those of the abdomen, after the 

 following manner: 



o 



A. Cervical Branches. The Superior Pharyngeal IJerve 

 (Ramus Pharyngeus) arises just below the preceding anastomo- 

 sis. It is directed downwards on the internal face of the in- 

 ternal carotid, and having sent an anastomotic filament to the 

 glosso-pharyngeal nerve, it forms on the middle constrictor of 

 the pharynx, the pharyngeal plexus which is re-enforced by 

 filaments from the superior cervical ganglion of the sympathetic, 

 from the glosso-pharyngeal, and from the superior laryngeal 

 nerve. The filaments departing from this plexus, are spent 

 principally upon the middle constrictor, but a few of them also 

 go to the superior constrictor; and others, descending along the 

 primitive carotid, anastomose with ramifications from the glos- 

 so-pharyngeal, and from the superficial cardiac nerve. A fila- 

 ment, called the inferior pharyngeal, sometimes proceeds from 

 the pneumogastric a little below the other, and also is spent upon 

 the pharynx. 



The pneumogastric, at the place where it detaches these pha- 

 ryngeal branches, or a little above them, becomes softened in 

 its texture, enlarges somewhat, and has the fasciculi which 

 compose it moderately separated by a sort of red gelatinous 

 substance interposed between them. ' This portion is its gang- 

 liform plexus, and into it is joined one or more branches from 

 the accessory nerve. 



The Superior Laryngeal Nerve (JVervus Laryngeus Superior] 

 arises from the ganglifofm plexus. It descends between the 

 internal carotid and the superior cervical ganglion, anasto- 

 mosing on the way with the latter, with the pharyngeal plexus, 

 and the hypo-glossal nerve; it then divides into an external 

 and an internal laryngeal branch. The former sends its fila^ 

 ments to the muscles situated on the fore part of the thyroid 

 cartilage; to the thyroid gland; and some of them penetrate 

 through the crico-thyroid membrane to the lining membrane of 

 the larynx. The internal laryngeal branch is placed above the 

 other; it is directed towards the thyreo-hyoid membrane, which 

 it penetrates and then begins to ramify. Some of the branches 



41* 



