PHAKYXGEAL, XERVES. 217 







Properties and Functions of the Phciryngeal Nemes. 

 The pharyngeal branches of the pneumogastric are mixed 

 nerves, their motor filaments being derived from the spinal 

 accessory. Their direct action upon the muscles of degluti- 

 tion belongs to the physiological history of the last-named 

 nerve. TTe have already stated, in treating of the spinal ac- 

 cessory, that the filaments of communication that go to the 

 pharyngeal branches of the pneumogastric are distributed to 

 the pharyngeal muscles. 1 



It is impossible to divide all of the pharyngeal filaments 

 in living animals and observe directly how far the general 

 sensibility of the pharynx and the reflex phenomena of deg- 

 lutition are influenced by this section. As far as we can 

 judge from the distribution of the filaments to the mucous 

 membrane, it would seem that they combine with the pha- 

 ryngeal filaments of the fifth, and possibly sensory filaments 

 from the glosso-pharyngeal, in giving general sensibility to 

 these parts. 



In some recent experiments by Waller and Prevost, on 

 the reflex phenomena of deglutition, it is shown that the ac- 

 tion of the pharyngeal muscles cannot be excited by stimu- 

 lation of the mucous membrane of the supralaryngeal region 

 and the pharynx, after section of the fifth and the superior 

 laryngeal branch of the pneumogastrics. 3 This would seem 

 to show that the pharyngeal branches of the pneumogastrics 

 are of little or no importance in these reflex phenomena. 



Properties and Functions of the Superior Laryngeal 

 Nei^ues. The distribution of these nerves points to a double 

 function ; viz., an action upon the crico-thyroid muscles, and 

 the important office of supplying general sensibility to the 

 upper part of the larynx and a portion of the surrounding 

 mucous membrane. 



1 See page 1 To. 



2 WALLER ET PRETOST, fitude relative crux nerfs semitifs qui president aiiz 

 pherwmenes reflexes de la deglutition. Archives de physiologic, Paris, 1870, tome 

 UL, p. 347. 



