558 CRANIAL NERYES. 



from the lower part of which two cords descend upon the oesophagus, on which 

 they divide, forming, with branches from the opposite nerve, the cesophageal 

 plexus ; below, these branches are collected into a single cord, which runs along 

 the back part of the oesophagus, enters the abdomen, and is distributed to the 

 posterior surface of the stomach, joining the left side of the cceliac plexus, and the 

 splenic plexus. 



On the left side, the pneumogastric nerve enters the chest, between the left 

 carotid and subclavian arteries, behind the left innominate vein. It crosses the 

 arch of the aorta, and descends behind the root of the left lung, and along the 

 anterior surface of the oesophagus to the stomach, distributing branches over its 

 anterior surface, some extending over the great cul-de-sac, and others along the 

 lesser curvature. Filaments from these latter branches enter the gastro-hepatic 

 omentum, and join the left hepatic plexus. 



The ganglion of the root is of a grayish color, circular in form, about two lines 

 in diameter, and resembles the ganglion on the large root of the fiftlj nerve. 



Connecting branches. To this ganglion the accessory portion of the spinal 

 accessory nerve is connected by several delicate filaments ; it also has an anasto- 

 motic twig with the petrous ganglion of the glosso-pharyngeal, with the facial 

 nerve by means of the auricular branch, and with the sympathetic by means of an 

 ascending filament from the superior cervical ganglion. 



The ganglion of the trunk (inferior) is a plexiform cord, cylindrical in form, of 

 a reddish color, and about an inch in length ; it involves the whole of the fibres 

 of the nerve, except the portion of tlje accessory nerve derived from the spinal 

 accessory, which blends with the nerve beyond the ganglion. 



Connecting branches. This ganglion is connected with the hypoglossal, the supe- 

 rior cervical ganglion of the sympathetic, and with the loop between the first and 

 second cervical nerves. 



The branches of the pneumogastric are 



In the jugular fossa . . Auricular. 



f Pharyngeal. 



In the neck. . . . J Superior laryngeal. 



] Recurrent laryngeal. 

 ^ Cervical cardiac. 

 f Thoracic cardiac. 



In the thorax. . J Anterior pulmonary. 



I Posterior pulmonary. 

 [_ (Esophageal. 



In the abdomen . . . Gastric. 



The Auricular branch arises from the ganglion of the root, and is joined soon 

 after its origin by a filament from the glosso-pharyngeal ; it crosses the jugular 

 fossa to an opening near the root of the styloid process. Traversing the substance 

 of the temporal bone, it crosses the aquasductus Fallopii about two lines above its 

 termination at the stylo-mastoid foramen ; it here gives off an ascending branch, 

 which joins the facial, and a descending branch, which anastomoses with the pos- 

 terior auricular branch of the same nerve ; the continuation of the nerve reaches 

 the surface between the mastoid process and the external auditory meatus, and 

 supplies the integument at the back part of the pinna. 



The Pharyngeal branch, the principal motor nerve of the pharynx and soft 

 palate, arises from the upper part of the inferior ganglion of the pneumogastric, 

 receiving a filament from the accessory portion of the spinal accessory ; it passes 

 across the internal carotid artery (in front or behind), to the upper border of the 

 Middle constrictor, where it divides into numerous filaments, which anastomose 

 with those from the glosso-pharyngeal, superior laryngeal, and sympathetic, to 

 form the pharyngeal plexus, from which branches are distributed to the muscles 

 and mucous membrane of the pharynx. As this nerve crosses the internal carotid, 

 some filaments are distributed, together with those from the glosso-pharyngeal, 

 upon the wall of this vessel. 



