730 THE NERVES. 



Near the origin of the occipital artery it crosses to the inner side of 

 that vessel, and beyond this is joined in the most intimate manner to the 

 cervical portion of the sympathetic chain ; the single cord resulting from 

 this fusion follows the common carotid artery, above which it is situated, 

 to near the entrance of the thorax. The two nerves then resume their 

 reciprocal independence, the pneumogastric penetrating the thorax a little 



Fig. 338. 



ORIGIN OF THE NERVES SPRINGING FROM THE MEDULLA OBLONGATA, AND PAR- 

 TICULARLY THAT OF THE PNEUMOGASTRiC, SPINAL, HYPOGLOSSAL, AND GLOSSO- 

 PHARYNGEAL. 



a, Medulla oblongata ; 6, Pyramids ; c, Enlargement simulating the olivary body ; 

 ?, Lateral posterior fissure ; <?, Fissure limiting superiorly the respiratory tract 

 of Ch. Bell ; /, Corpus restiforme ; g, Auditory nerve ; A, External oculo-motor ; 



1, Trigeminus ; j, Arciform fibres of the medulla oblongata. 1, Pneumogastric ; 



2, Spinal, inner root ; 3, Glosso-pharyngeal ; 4, Spinal, medullary column ; 5, 

 Inferior, or anterior, root of the great hypoglossal ; 5', Its ganglionic root ; 6, 

 Facial ; 7, Jugular ganglion ; 8, Anastomosis of the pneumogastric with the 

 facial ; 9, Ramuscule from the external branch of the spinal passing to the pneu- 

 mogastric. From Toussaint's Thesis on the ' Anatomie Comparee du Nerf 

 Pneumogastrique.' Lyons, 1869. 



below the sympathetic, in passing among the lymphatic glands existing 

 between the two first ribs. 



In this course, the two pneumogastrics affect nearly the same relations; 

 though there is something special connected with the left, which corres- 

 ponds with the oesophagus towards the lower part of the neck. 



Within the chest, however, these two nerves comport themselves a 



