THE FACIAL. 549 



of facial paralysis, where the lesion is deep seated. The paralysis is 

 recognized by an incapacity to lift the soft palate, which hangs down in 

 a passive manner, and by the deviation of the uvula, which, according to 

 the observations recorded by Longet, is always toward the sound side. 

 The levator palati, and especially the uvular muscle, being paralyzed, its 

 fellow in contracting draws the uvula into an oblique position, with its 

 point directed toward the non-paralyzed side. As there is no other 

 communication between the facial nerve and the palatal muscles, than 

 that through the sphenopalatine ganglion by the great superficial petro- 

 sal nerve, this nerve must be regarded as containing motor fibres running 

 from the facial to the ganglion. 



A little below the origin of the last-mentioned filament, the facial nerve 

 gives off a second, the small superficial petrosal nerve do ), which com- 

 municates both with the otic ganglion and with the plexus of nerve 

 filaments on the inner wall of the tympanum, known as the " tympanic 

 plexus," which supplies nerve fibres to the lining membrane of the 

 tympanic cavity, while the otic ganglion sends a motor filament to the 

 tensor tympani muscle. 



From the concave border of the facial nerve, as it bends downward, a 

 fine motor filament, the stapedius branch (n), passes forward to supply 

 the stapedius muscle. The facial nerve, therefore, in this part of its 

 course, has an influence on the mechanism of hearing, through the 

 muscles which regulate the position of the bones of the middle ear, and 

 consequently the tension of the membrana tympani. This influence is 

 exerted directly by its stapedius branch, and indirectly, through the otic 

 ganglion, by the filament supplied to the tensor tympani. Cases of 

 facial paralysis have been known to be accompanied, sometimes by par- 

 tial deafness, and sometimes by abnormal sensibility to sonorous im- 

 pressions ; but it has not been determined how far these symptoms were 

 due to the implication of other parts, or how far to paralysis of the 

 muscles of the middle ear from disease of the facial. 



From its descending portion, the facial nerve gives off two small 

 branches of communication ( 12, 13 ), one to the pneumogastric and one 

 to the glossopharyngeal nerve. They are usually regarded as motor 

 filaments, which transmit to these two nerves the power of causing mus- 

 cular contraction. This seems nearly certain in regard to the branch 

 communicating with the glossopharyngeal nerve ; since Cruveilhier de- 

 scribes a separate filament of the facial passing to the styloglossus and 

 palato-glossus muscles, and Longet cites an instance in which a branch 

 of the facial, on one side, without making any connection with the glosso- 

 pharyngeal nerve, was distributed directly to the palato-glossal and 

 glossopharyngeal muscles ; that is, to the constrictors of the isthmus 

 of the fauces. 



, Finally the facial nerve, shortly before its exit from the stylomastoid 

 foramen, gives off from its concave border another slender branch of 

 considerable interest, the chorda tympani (u). It first passes upward 

 and forward, in a recurrent direction, traverses the cavity of the tym- 



