912 NEUROLOGY 



medius, where it divides into numerous filaments, which join with branches from 

 the glossopharyngeal, sympathetic, and external laryngeal to form the pharyngeal 

 plexus. From the plexus, branches are distributed to the muscles and mucous 

 membrane of the pharynx and the muscles of the soft palate, except the Tensor 

 veli palatini. A minute filament descends and joins the hypoglossal nerve as it 

 winds around the occipital arteny. 



The Superior Laryngeal Nerve (n. laryngeus superior} larger than the preceding, 

 arises from the middle of the ganglion nodosum and in its course receives a branch 

 from the superior cervical ganglion of the sympathetic. It descends, by the side of 

 the pharynx, behind the internal carotid artery, and divides into two branches, 

 external and internal. 



The external branch (ramus externus), the smaller, descends on the larynx, beneath 

 the Sternothyreoideus, to supply the Cricothyreoideus. It gives branches to the 

 pharyngeal plexus and the Constrictor pharyngis inferior, and communicates with 

 the superior cardiac nerve, behind the common carotid artery. 



The internal branch (ramus interims) descends to the hyothyroid membrane, 

 pierces it in company with the superior laryngeal artery, and is distributed to the 

 mucous membrane of the larynx. Of these branches some are distributed to the 

 epiglottis, the base of the tongue, and the epiglottic glands; others pass backward, 

 in the ary epiglottic fold, to supply the mucous membrane surrounding the entrance 

 of the larynx, and that lining the cavity of the larynx as low down as the vocal 

 folds. A filament descends beneath the mucous membrane on the inner surface 

 of the thyroid cartilage and joins the recurrent nerve. 



The Recurrent Nerve (n. recurrens; inferior or recurrent laryngeal nerve) arises, 

 on the right side, in front of the subclavian artery; winds from before back- 

 ward around that vessel, and ascends obliquely to the side of the trachea behind 

 the common carotid artery, and either in front of or behind the inferior thyroid 

 artery. On the left side, it arises on the left of the arch of the aorta, and winds 

 below the aorta at the point where the ligamentum arteriosum is attached, and then 

 ascends to the side of the trachea. The nerve on either side ascends in the groove 

 between the trachea and esophagus, passes under the lower border of the Con- 

 strictor pharyngis inferior, and enters the larynx behind the articulation of the. 

 inferior cornu of the thyroid cartilage with the cricoid; it is distributed to all the 

 muscles of the larynx, excepting the Cricothyreoideus. It communicates with the 

 internal branch of the superior laryngeal nerve, and gives off a few filaments to 

 the mucous membrane of the lower part of the larynx. 



As the recurrent nerve hooks around the subclavian artery or aorta, it gives 

 off several cardiac filaments to the deep part of the cardiac plexus. As it ascends 

 in the neck it gives off branches, more numerous on the left than on the right side, 

 to the mucous membrane and muscular coat of the esophagus; branches to the 

 mucous membrane and muscular fibers of the trachea; and some pharyngeal 

 filaments to the Constrictor pharyngis inferior. 



The Superior Cardiac Branches (rami cardiaci superiores; cervical cardiac branches), 

 two or three in number, arise from the vagus, at the upper and lower parts of the 

 neck. 



The upper branches are small, and communicate with the cardiac branches 

 of the sympathetic. They can be traced to the deep part of the cardiac plexus. 



The lower branch arises at the root of the neck, just above the first rib. That 

 from the right vagus passes in front or by the side of the innominate artery, and 

 proceeds to the deep part of the cardiac plexus; that from the left runs down across 

 the left side of the arch of the aorta, and joins the superficial part of the cardiac 

 plexus. 



The Inferior Cardiac Branches (rami cardiaci inferiores; thoracic cardiac branches), 

 on the right side, arise from the trunk of the vagus as it lies by the side of the 





