PXEUMO-GASTRIC NERVE. 



619 



by the internal jugular vein and the internal carotid artery, and afterwards 

 similarly between that vein and the common carotid artery, being enclosed 

 along with them in the sheath of the vessels. As they enter the thorax, 

 the nerves of the right and left side present some points of difference. 



Fig 416. DIAGRAM OF THE ROOTS Fig. 416. 



AND ANASTOMOSING BRANCHES OF 

 THE NERVES OF THE EIGHTH PAIR 

 AND NEIGHBOURING NERVES (from 

 Sappey after Hirschfeld and Le- 

 veille). 



1, facial nerve ; 2, glosso-pharyn- 

 geal with the petrous ganglion repre- 

 sented ; 2', connection of the digastric 

 branch of the facial neive with the 

 glosso-pharyngeal nerve ; 3, pneu- 

 mo-gastric, with both its ganglia re- 

 presented ; 4, spinal access ry ; 5, 

 hypoglossal ; 6, superior cervical 

 ganglion of the sympathetic ; 7, loop of 

 union between the two first cervical 

 nerves ; 8, carotid branch of the sym- 

 pathetic ; 9, nerve of Jacobson (tym- 

 panic), given off from the petrous 

 ganglion ; 10, its filaments to the 

 sympathetic; 11, twig to the Eusta- 

 chian tube ; 12, twig to the fenestra 

 ovalis; 13, twig to the fenestra ro- 

 tun'la ; 14, twig of union with the 

 small superficial petrosal ; 15, twig of 

 union with the large superficial petro- 

 s tl ; 16, otic ganglion ; 17, branch of 

 the jugular fossa, giving a filament to 

 the petrous ganglion ; 18, union 

 of the spinal accessory with the pneu- 

 mo-gastric ; 19, union of the hypo- 

 glossal with the first cervical nerve ; 

 20, union between the sterno-mastoid 

 branch of the spinal accessory and 

 that of the second cervical nerve ; 21, 



pharyngeal plexus ; 22, superior laryngeal nerve ; 23, external laryngeal ; 24, middle 

 cervical ganglion of the sympathetic. 



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

 clavian artery, at the root of the neck, and its recurrent laryngeal branch 

 turns backwards and upwards round that vessel. The n rve then enters 

 the thorax behind the right innominate vein, and descends on the side of the 

 trachea to the back of the root of the lung, where it spreads out in the pos- 

 terior pulmonary plexus. It emerges from this plexus in the form of two 

 cords, which are directed to the resophagus. and uniting and subdividing 

 form, with similar branches of the nerve of the left side, the oesophageal 

 plexus. Near the lower part of the oesophagus the branches, which have 

 thus interchanged fibres with the nerve of the left side, are gathered 

 again into a single trunk, which, descending on the back of the oesophagus, 

 is spread out on the posterior or inferior surface of the stomach. 



On the left side the pueumo-gastric nerve, entering the thorax between 

 the left carotid and subclavian arteries and behind the left innominate vein, 

 lies further forwards than the right nerve, and crosses over the arch of the 

 aorta, while its recurrent laryngeal branch turns up behind the arch. It 



s s 2 



