CRANIAL NERVES. 317 



fourth ventricle. It passes through the posterior lacer- 

 ated foramen, lies upon the stylo-pharyngeus and middle 

 constrictor muscles, then runs along the inner surface of 

 the hyoglossus muscle and is distributed to the mucous 

 membrane of the tongue, pharynx, tonsils, and mouth. 

 This nerve presents two ganglionic enlargements, one 

 just above the jugular foramen (the jugular ganglion), 

 the other within the jugular canal (the petrosal gan- 

 glion). The branches of the glosso-pharyngeal are : the 

 communicating, with the pneumogastric and sympathetic ; 

 the tympanic, which is distributed to the promontory of 

 the tympanum ; the muscular, and its terminal branches 

 to the pharynx, palate, tonsils, and tongue. 



10. PNEUMOGASTRIC. A motor and sensory nerve 

 'distributed to pharynx, larynx, heart, lungs, liver, and 

 intestines. It arises by a series of fibres from the groove 

 between the olivary and restiform bodies, below the origin 

 of the glosso-pharyngeal. Its deep origin is from the 

 floor of the fourth ventricle, close to the origin of the 

 glosso-pharyngeal, and associated with the nucleus of the 

 fifth pair. It passes out of the skull by the posterior 

 lacerated foramen, and presents in this region two gan- 

 glia, that of the root and that of the'trunk, the latter 

 situated just below the jugular foramen. The pneumo- 

 gastric passes down the neck in the sheath of the carotid 

 artery, between it and the internal jugular vein, but on a 

 plane posterior to them, down to the sixth cervical verte- 

 bra, where its course on the two sides of the neck is 

 different. On the right side the pneumogastric lies on 

 the subclavian artery, and runs down along the right 

 side of the trachea to its bifurcation ; it passes behind 

 the right bronchus to the posterior part of the oesopha- 

 gus, passes through the oesophageal opening in the dia- 

 phragm, and is distributed to the stomach, forming 



