24 ELEMENTARY PHYSIOLOGY. 



name means double-beaded, and this muscle is so 

 called because it lias two upper tendons or starting 

 places. Here (32) is the one, and here (33) is the 

 other. The return of the muscle to its usual shape 

 and length is called its relaxation. The relaxation 

 of this (34) biceps must take place to permit the 

 arm to straighten out; but, at the same time, some 

 other muscle or muscles must contract to move it 

 into the straight position. A muscle which bends a 

 part is called a flexor. One which serves to 

 straighten a part is called an extensor. 

 . . ._ Most of the muscles of the body are 



Antagonists, J 



or counter paired off in their work. That is, the 

 motion of a part produced by a certain 

 muscle is reversed by the contraction of some other 

 muscle. Such muscles are called antagonists, or 

 counter muscles. Here again we refer to the chart 

 for illustration. To raise the forearm, as we have 

 seen, this (34) biceps must contract ; but to straighten 

 it out again requires the action of this muscle (36), 

 the triceps. So the biceps and triceps are antag- 

 onists. These muscles (43 and 44) bend the fingers, 

 while these (51 and 52) straighten or extend them 

 another illustration of counter muscles. 



The names of the muscles are very 



Prominent . 



and long and difficult to remember. It 



Their Names. wou u be unwise and unreasonable 

 to ask you now to learn many of them. But by 

 studying a few of the more prominent ones you will 

 learn something about their uses, and also how their 



