NERVES 155 



The IOTH NERVE the PNEUMOGASTRIC or VAGUS. Origin 

 Superficial ; sulcus, between restiform and olivary bodies. 

 Deep : Trigonum vagi on floor of 4th ventricle. 



Course. Passes from origin over the flocculus to jugular 

 foramen, through which it passes in same sheath with spinal 

 accessory and behind the glosso-pharyngeal ; in the foramen 

 it presents the ganglion of the root. Upon leaving the fora- 

 men, it is connected with the accessory part of the spinal 

 accessory, and forms an enlargement, the ganglion of the 

 trunk. The accessory part of the spinal accessory nerve 

 passes over the ganglion, some fibres joining the trunk of the 

 nerve, but the principal portions are continued into the 

 pharyngeal and superior laryngeal branches. Thence the 

 nerve passes down in the carotid sheath, behind and between 

 the artery and vein, to the root of the neck, where its course 

 on each side of the body becomes different. 



The right nerve passes between ist part of subclavian artery 

 and subclavian vein, and down by side of trachea and behind 

 right innominate vein to posterior part of the root of the right 

 lung, forming the posterior pulmonary plexus ; thence proceed 

 two cords, which run down on the oesophagus, communicate 

 with nerve of opposite side (cesophageal plexus), join belowinto 

 one trunk, which lies behind oesophagus, and passing through 

 cesophageal orifice in diaphragm is distributed to the posterior 

 surface of the stomach, joining solar and splenic plexuses. 



The left nerve passes down between the left subclavian and 

 carotid arteries, and behind the left innominate vein, where 

 the left phrenic crosses it ; thence in front of the arch of aorta 

 to posterior surface of root of left lung, forming the posterior 

 pulmonary plexus; then along the anterior surface of 

 oesophagus through diaphragm, to be distributed on the 

 anterior surface of stomach, and join left hepatic plexus. 



Connecting branches : 



The ganglion of the root is connected to the spinal accessory, 

 petrous ganglion of the glosso-pharyngeal and sympathetic 

 nerves. 



The ganglion of the trunk is connected with the hypo- 

 glossal, sympathetic, and loop between ist and 2nd cervical 

 nerves. 



Branches : 



Recurrent : from the upper ganglion, passes backwards to 

 the dura mater of the posterior fossa. 



Auricular (Arnold's) : from the ganglion of the root, com- 

 municates with the petrous ganglion of the glosso-pharyngeal, 

 and enters a foramen between the root of the styloid process 



