THE FIFTH CRANIAL NERVE. 523 



on to the gland. (2.) To the submaxillary gland by the chorda 

 tyinpani, which after traversing the tympanum leaves the ear by 

 a fissure at its anterior extremity, then joins the lingual branch 

 of the fifth to separate from it and pass into the submaxillary 

 ganglion which lies in close relation to the gland (compare Figs. 

 64 and 65). 



iii. Vaso-motor, or vaso-inhibitory influences, are chiefly con- 

 nected with the secretory function, since dilatation of the vessels 

 of the glands accompanies the increased secretion that follows 

 stimulation of the nerves going to the glands. 



iv. The following afferent impulses are said to travel along the 

 track of the portio dura and its branches: (1.) Special taste-sen- 

 sations, which are chiefly located in the chorda tympani branch, 

 may be explained by the branches of communication which pass 

 from the trunk and petrous ganglion of the glosso-pharyngeal to 

 the portio dura at its exit from the foramen, or by the connection 

 in the drum of the ear between the tympanic branch of the glos- 

 so-pharyngeal and the geniculate ganglion of the portio dura 

 .through the lesser superficial petrosal nerve. (2.) Ordinary sen- 

 sations, which are also located in. the chorda tympani, are said to 

 traverse this nerve in an afferent direction until it comes near the 

 otic ganglion, when the sensory fibres leave the chorda and pass 

 to the inferior division of the fifth nerve through the otic ganglion. 



Injury of the facial nerve in any of the deeper parts of its 

 course gives rise to the striking group of symptoms known as facial 

 paralysis, the details of which are too long to be given here. 

 When it is remembered that muscles aiding in expression, masti- 

 cation, deglutition, hearing, smelling, and speaking, are paralyzed, 

 and that taste, salivary secretion, and possibly ordinary sensation 

 are impaired, one can form some idea of the complex pathological 

 picture such a case presents. 



V. N. TRIGEMINUS, OR TRIFACIAL NERVE. 



This nerve transmits both efferent and afferent impulses, which, 

 however, are carried by two different strands of fibres. The motor 

 part, which arises from a gray nucleus in the floor of the fourth 



