148 NERVOUS SYSTEM. 



to enter into a farther discussion of these facts, which are ac- 

 cepted by nearly all writers upon diseases of the nervous sys- 

 tem, and may be regarded as settled ; 1 and the only question 

 is, how far they can be explained by the anatomy of the parts. 



As we have just seen, the fibres of origin of the facial 

 have been traced to the floor of the fourth ventricle, where 

 a few decussate, but the rest are lost. Ths question now is, 

 whether or not the fibres pass up through the pons, and de- 

 cussate above, as the pathological facts just noted would 

 seem to indicate. Anatomical researches upon this point 

 are entirely unsatisfactory ; and the existence of such a de- 

 cussation has never been clearly demonstrated. The patho- 

 logical observations, nevertheless, remain ; and, however in- 

 definite anatomical researches may have been, there can be 

 no doubt that lesions in one-half of the pons affect the facial 

 upon the same side, while lesions above have a crossed ac- 

 tion. The most that we can say upon this point is, that it 

 is a reasonable inference from pathological facts that the 

 nerves decussate anterior to the pons. 



It will be only necessary to describe in a general way the 

 course of the fibres of distribution of the facial. The main 

 root of the facial, the auditory nerve, and the delicate inter- 

 mediary nerve of Wrisberg pass together into the internal 

 auditory rneatus. At the bottom of the meatus, the facial 

 and the nerve of Wrisberg enter the aqueeductus Fallopii, 

 following its course through the petrous portion of the tem- 

 poral bone. In the aqueduct, the nerve of "Wrisberg pre- 

 sents a little ganglioform enlargement, of a reddish color, 

 which has been shown to contain nerve-cells. 2 The main 



1 The reader is referred for a fuller consideration of these points to the re- 

 cent standard works upon practical medicine. The most complete collection of 

 cases of the so-called alternate paralysis was published by Gubler, in the Ga- 

 zette hebdomadaire de medecine et chirurgie, Paris, 1856, and in the volumes of 

 the same journal for 1858 and 1859. A characteristic case has lately been re- 

 ported by Prof. Hammond, in the Journal of Psychological Medicine, New York, 

 1871, vol. v., p. 14. 



8 SAPPEY, Traite d 1 'anatomic descriptive, Paris, 1862, tome ii., p. 254. 



