350 NEUROLOGY, OR ANATOMY OF NERVOUS SYSTEM 



The Pneumogastric Nerve 



The tenth, vagus, or pneumogastric is both motor and sen- 

 sory. Its apparent origin is by twelve to fifteen filaments 

 from the groove between the olive and restiform bodies, 

 below, and in the line of the origin of the ninth; its deep origin 

 is from a nucleus in the lower part of the fourth ventricle. It 

 passes through the jugular foramen in the same sheath with 

 the spinal accessory, a partition separating them from the 

 ninth, and develops the ganglion of the root of the vagus. Emerg- 

 ing from the foramen, it forms the ganglion of the trunk of the 

 vagus. 



The ganglion of the root (ganglion jugulare) is gray in color 

 and spherical, its diameter about two lines. It has branches 

 of communication with the accessory part of the spinal acces- 

 sory, with the petrous ganglion of the ninth, with the facial, 

 and with the superior cervical ganglion of the sympathetic. 



The ganglion of the trunk (ganglion cervicale) is larger, of 

 a reddish color and cylindrical form. Its surface is crossed 

 by the accessory portion of the eleventh, and it communicates 

 with the hypoglossal, the upper two cervical, and the sym- 

 pathetic nerves. 



The vagus then descends between the internal carotid artery 

 and the jugular vein to the thyroid cartilage, then between 

 the vein and the common carotid to the root of the neck. 



On the right side the nerve crosses the first part of the sub- 

 clavian artery, descends behind the right innominate vein 

 and alongside of the trachea, and spreads out into the posterior 

 pulmonary plexus behind the root of the lung. Below, two 

 cords emerge from this plexus and ramify on the esophagus, 

 forming, with branches from the left, the esophageal plexus. 

 Again, forming a single trunk, the nerve descends on the back 

 of the esophagus to ramify on the posterior surface of the 

 stomach. 



On the left side the nerve runs behind the left innominate 

 vein, between the left carotid and subclavian arteries, and 

 crosses the arch of the aorta. It forms the left posterior pul- 

 monary plexus, assists to form the esophageal plexus, and as 

 a single trunk descends on the front of the esophagus to ramify 

 on the anterior surface of the stomach. 



