

 SUBLINGTJAL NEEVE. 179 



> 



into the gray matter of the floor of the fourth ventricle, be- 

 tween the deep origin of the pneumogastric and the glosso- 

 pharyngeal. Though there is much difference of opinion 

 upon this point, it is probable, from the elaborate researches 

 of Dr. Dean, 1 that some of the filaments of origin of these 

 nerves decussate in the floor of the fourth ventricle. 



The superior and inferior filaments of origin of the nerve 

 unite respectively to form two bundles, which pass through 

 distinct perforations in the dura mater. These two bundles 

 then pass into the anterior condyloid foramen, and unite into 

 a single trunk as they emerge from the cranial cavity. In 

 some of the inferior animals, the calf, horse, pig, rabbit, dog, 

 and cat, there is a delicate filament arising from the latero- 

 posterior portion of the medulla, remarkable by the presence 

 of a small ganglion, which joins the trunk of the nerve as it 

 passes through the foramen. This was described by Mayer, 

 and more lately by Yulpian ; both of these observers having 

 noted it exceptionally in the human subject. 8 Direct experi- 

 ments are wanting to show positively the physiological prop- 

 erties of this ganglionic root. 



After the sublingual has passed out of the cranial cavity, 

 it anastomoses with several nerves. It sends a filament of 

 communication to the sympathetic as it branches from the 

 superior cervical ganglion. Soon after it has passed through 

 the foramen, it sends a branch to the pneumogastric. It 

 anastomoses by two or three branches with the upper two 

 cervical nerves, the filaments passing in both directions be- 

 tween the nerves. It anastomoses with the lingual branch of 

 the fifth, by two or three filaments passing in both directions. 



In its distribution, the sublingual presents several re- 

 markable peculiarities. 



Its first branch, the descendens noni, passes down the 



1 DEAN, The Gray Substance of the Medulla Oblongata and Trapezium, Wash- 

 ington, 1864, p. 16. 



8 VULPIAH, Sur la racine posterieure ou ganglionnaire du nerf hypoglosse. 

 Journal de la physiologic, Paris, 1862, tome v., p. 5, et seq. 



