PNEUMOGASTRIC NERVE BRANCHES. 395 



which 'communicate with each other, with the other divisions of the 

 eighth pair, and with the trunk of the pneumogastric below the 

 ganglion. This second, or plexifonn ganglion (ganglion of the su- 

 perior laryngeal branch, of Sir Astley Cooper), is situated, at first, 

 behind the internal carotid artery, and then between that vessel and 

 the internal jugular vein. The pneumogastric nerve then descends 

 the neck within the sheath of the carotid vessels, lying behind and 

 between the artery and vein, to the root of the neck. Here the 

 course of the nerve at opposite sides becomes different. 



The Right passes between the subclavian artery and vein to the 

 posterior mediastinum, then behind the root of the lung to the 0330- 

 phagus, which it accompanies to the stomach, lying on its posterior 

 aspect. 



The Left enters the chest parallel with the left subclavian artery, 

 crosses the arch of the aorta, and descends behind the root of the 

 lung, and along the anterior surface of the oesophagus, to the 

 stomach. 



The fibres of origin of the pneumogastric nerve, like those of the 

 glosso-pharyngeal, may be traced through the fasciculi of the 

 corpus restiforme into the gray substance of the floor of the fourth 

 ventricle. 



The Branches of the pneumogastric nerve are the following : 



Communicating branches with the Facial, 



Glosso-pharyngeal, 

 Spinal accessory, 

 Hypo-glossal, 

 Sympathetic. 

 Pharyngeal, 

 Superior laryngeal, 

 Cardiac, 



Inferior or recurrent laryngeal, . 



Pulmonary anterior, 

 Pulmonary pos&rior, 

 CEsophageal, 

 Gastric. 



* . 



The Branches of communication form part of the complicated 

 plexus at the base of the skull. The branches to the ganglion of 

 Andersch, and that to the facial nerve, are given off by the superior 

 ganglion in the jugular fossa ; the latter passes through a minute 

 canal in the petrous bone, to the lower part of the aqueductus 

 Fallopii. 



The Pharyngeal nerve arises from the pneumogastric, immediately 

 above the plexiform ganglion, and descends behind the internal 

 carotid artery to the upper border of the middle constrictor, upon 

 which it forms the pharyngeal plexus assisted by branches from the 

 glosso-pharyngeal, superior laryngeal, and sympathetic. The pharyn- 



