THE NERVOUS SYSTEM. 609 



vago-accessory nuclei lie outside of, close to, and parallel with the nucleus 

 of the twelfth. 



Distribution. It supplies sensory branches, which accompany the 

 sympathetic on the middle meningeal artery, and others which supply 

 the back part of the meatus and the adjoining part of the external ear. 

 It is connected with the petrous ganglion of the glosso-pharyngeal, by 

 means of fibres to its jugular ganglion; with the spinal accessory which 

 supplies it with its motor fibres for the larger and upper portion of the 

 oesophagus, and with its inhibitory fibres for the heart; also with the 

 twelfth; with the superior cervical ganglion of the" sympathetic; and 

 with the cervical plexus. It has, of all the nerves, the most varied dis- 

 tribution and functions, either through its own filaments, or through 

 those which, derived from other nerves, are mingled in its branches. 

 The parts supplied by the branches of the vagus are as follows : 



(1.) By its pharyngeal branches, which enter the pharyngeal plexus, 

 a large portion of the mucous membrane, and, probably, all the muscles 

 of the pharynx. 



(2.) By the superior laryngeal nerve, the mucous membrane of the 

 under service of the epiglottis, the glottis, and the greater part of the 

 larynx, and the crico-thyroid muscle. 



(3.) By the inferior laryngeal nerve, the mucous membrane and mus- 

 cular fibres of the trachea, the lower part of the pharynx and larynx, 

 and all the muscles of the larynx except the crico-thyroid. 



(4.) By its cesophageal branches, the mucous membrane and muscular 

 coats of the oesophagus. 



(5.) Through the cardiac nerves, moreover, the branches of the vagus 

 form a large portion of the supply of nerves to the heart and the great 

 arteries. 



(6.) Through the anterior and the posterior pulmonary plexuses to the 

 lungs. 



(7.) Through its gastric branches to the stomach; and to the intes- 

 tines, and kidneys, by its terminal branches. 



(8.) Through its hepatic and splenic branches, the liver and the spleen 

 are partly supplied with nerves. 



Functions. Throughout its whole course, the vagus contains both 

 sensory and motor fibres. To summarize the many functions of this 

 nerve, which have been for the most part considered in the preceding 

 chapters, it may be said that it supplies (1) motor influence to the 

 pharynx and oesophagus, stomach and intestines, to the larynx, trachea, 

 bronchi, and lung; (2) sensory and, in part, (3) vaso-motor influence, 

 to the same regions ; (4) inhibitory influence to the heart; (5) inhibi- 

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