256 pEmciPLEs OF vbtebinaet surgery 



How is the more or less rapid atrophy of a paralyzed muscle 

 explained f 

 When the functional activity of the motor tract is inter- 

 rupted before the motor fibers connect with the large multi- 

 polar cells in the inferior gray horn of the spinal cord, the 

 nutrition of the paralyzed muscle is only disturbed by the in- 

 activity of that muscle ; in other words, there is an inactivity 

 atrophy and no degenerative changes in the muscular fibers 

 themselves, simply because the trophic motor ganglia — ^that 

 is, the multipolar cells in the gray horn — are not disturbed in 

 their nutritional influence which they exert over the nerve 

 and muscle. But as soon as these ganglia themselves are dis- 

 eased, or the active cause of the paralysis lies back of them, 

 thus interrupting their nutritional influence over the nerve 

 and muscle, a rapid degenerative atrophy sets in. 



Of what value are these points in regard to the prognosis of a 



paralysis ? 



In inactivity atrophy, the nutrition of the nerve and 

 muscle not being interfered with, restitution under certain 

 circumstances is possible; while in those cases of paralysis 

 with destruction of the trophic elements of the nerve and 

 muscle, permanent and irreparable damage renders the prog- 

 nosis unfavorable, as far as the muscle and nerve are con- 

 cerned. 



What do you understand by the reaction of degeneration ? 



A modification in the electric properties of paralyzed 

 nerves and muscles. 



What do you understand hy the electrical properties of nmS' 

 cles and nerves ? 



Healthy nerves and muscles, when exposed to electric 

 stimulation, respond to it in a precise manner. When dis- 



