88 



THE PHYSIOLOGY OP MUSCLE AND NERVE. 



conductor of the electrical current, and to reduce the resistance at the 

 points at which the electrodes come in contact with the skin each is 

 covered with cotton or chamois skin kept moistened with a dilute 

 saline solution. 



Motor Points. By means of the unipolar method nearly every 

 voluntary muscle of the body may be stimulated separately. All 

 that is necessary, when the induced current is used, is to bring the 

 active electrode as nearly as possible over the spot where the 



M. triceps (caput 



longum) 



M. flexor carpi ulnaris 



M. flex, digitor. sub- 

 lim. (digiti II et III) 



M. flex, digit, subl. 

 (digit: Ridicis et 

 minimi) 



Jferv. ulnaris 



M. flexor digit, min. 



M. opponeos digit. 



min. 



M. abductor polUc. brer. 

 M. opponens pollicis 



M. flex. poll. brev. 



M. adductor pollic. bref. 



Fig. 34. Motor points in upper extremity. 



muscle receives its motor branch. A diagram showing these motor 

 points for the arm is given in Fig. 34. In the same way the nerves 

 of the brachial plexus and other nerve trunks may be stimulated very 

 readily through the skin. When the induction current is used no 

 distinction can be made between the cathodic and anodic effects. 

 When, however, the battery current is employed one may make 

 the stimulating electrode either anode or cathode, and under these 

 circumstances a marked difference is observed in the strength of 



