THE CRANIAL NERVES 



to the oesophagus and the inferior constrictor of the pi 

 nerve is distributed to all the muscles of the larynx, except the crico- 

 thyroid already supplied by the su- 

 perior laryngeal. The larynx there- 

 fore receives from the pneumogastric 

 two different branches, of distinct 

 properties and functions. The supe- 

 rior laryngeal branch is mainly a sen- 

 sitive nerve, supplying the mucous 

 membrane; the inferior laryngeal 

 branch is motor, and provides for the 

 activity of the laryngeal muscles. 



The most important dependency of 

 the pneumogastric nerve in the chest 

 is the pulmonary plexus. This is 

 formed by a number of inosculating 

 branches, from which the filaments 

 of distribution pass, along the bronchi 

 and their subdivisions, to the pulmo- 

 nary lobules. In the inferior portion 

 of the chest, other inosculating branches 

 surround the oesophagus with the 

 oesophageal plexus, from which fibres 

 are supplied to its mucous membrane 

 and muscular coat. 



The pneumogastric nerves, after re- 

 union of their branches below the pul- 

 monary plexus, enter the abdomen 

 and spread out in two sets of gastric 

 branches, which supply the mucous 

 membrane and muscular coat of the 

 stomach. Those from the left pneu- 

 mogastric nerve supply the anterior 



wall of the organ, and send filaments ORIGIN AND CONNECTIONS OF THE GLOSSO- 



to the transverse fissure of the liver, 

 into which they penetrate in company 

 with the hepatic plexus of the sympa- 

 thetic ; those from the right pneumo- 

 gastric supply the posterior wall of 

 the stomach, and finally communicate 

 with the solar plexus of the sympa- 

 thetic. 



The pneumogastric nerve, therefore, is distributed to the passages 

 by which air and food are introduced into the body. It also forms con- 

 nection at several points with the great sympathetic, and, through it, 

 sends fibres to the heart. 



Physiological Properties of the Pneumogastric. According to Lon- 



PHARYNGEAL, PNEUMOGASTRIC, AND SPI- 



NAL ACCESSORY NERVES. 1. Facial nerve. 

 2. Glossopharyngeal. 3. Pneumogastric. 

 4. Spinal accessory. 5. Hypoglossal. 6. 

 External (muscular) branch of the spinal 

 accessory. 7. Superior laryngeal branch 

 of the pneumogastric. 8. Pharyngeal 

 plexus. 9. Laryngeal plexus and upjper 

 cardiac branches of the pneumogastric. 

 10. Tympanic plexus, from a branch of 

 the glossopharyngeal. (Hirschfeld.) 



