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TEXT-BOOK OF PHYSIOLOGY. 



muscle contraction than others. It was subsequently discovered by Remak 

 that these points coincide with the entrance of the nerve into the muscle. 

 It is to these motor points that the one electrode should be applied. The 

 position of some of these points on the forearm is shown in Fig. 58. 



Reactions of Degeneration. In consequence of the degeneration 

 and changes in irritability which occur in nerves when separated from their 

 centers and in muscles when separated from their related nerves, either 

 experimentally or as the result of disease, the response of these structures to 

 the induced, and the make and break of the constant current, differs from 

 that observed in the physiologic condition. The facts observed under the 

 application of these two forms of electricity are of importance in the diagnosis 



M. biceps brachii. 



M. brach. anticus. 

 N. medianus. 



M. pronator teres. 



M. flex, digitor. commun. profund. 

 M. flex, carpi radialis. 



M. flex, digitor. sublim. 



M. flex. dig. subl. (dig. ind. et min.) 

 L M. flex. poll, 

 longus. 



N. ulnaris. 



M. flexor carpi ulnaris. 



N. ulnaris. 



FIG. 58. MOTOR POINTS OF THE MEDIAN AND ULNAR NERVES, WITH THE MUSCLES 

 SUPPLIED BY THEM. (Landois and Stirling.} 



and therapeutics of the precedent lesions. The principal difference of 

 behavior is observed in the muscles, which exhibit diminished or abolished 

 excitability to the induced current, while at the same time manifesting 

 an increased excitability to the constant current; so much so is this the 

 case that a closing contraction is just as likely to occur at the positive as 

 at the negative pole. This peculiarity of the muscle response is termed 

 the reaction of degeneration. The synchronous diminished excitability of the 

 nerves is the same for either current. The term "partial reaction of degen- 

 eration" is used when there is a normal reaction of the nerves, with the de- 

 generative reaction of the muscles. This condition is observed in progressive 

 muscular atrophy. 



Reflex Action. Inasmuch as many of the muscle movements of 

 the body, as well as the formation and discharge of secretions from glands, 

 variations in the caliber of blood-vessels, inhibition and acceleration in 

 the activity of various organs, are the result of stimulations of the terminal 

 organs of afferent nerves, they are termed, for convenience, reflex actions, 

 and, as they take place for the most part through the spinal cord and medulla 



