THE PRINCIPLES OF MYODYNAMICS. 23 



(iv.) The rectus femoris is a double oblique 

 fibred muscle. 



(v.) The diaphragm is a radiate fibred muscle. 



1 5. In regard to motion and power as ex- 

 hibited by muscles the following statements may 

 be made : — 



(i.) The longer the fibres of a muscle the more 

 extensive is the motion it can make and the 

 greater its power. 



(2.) The power of a muscle increases as the 

 number of its fibres increases : The muscle 

 whose transverse section has the greatest area 

 will have the greatest power. 



(3.) Other things being equal, the proper use 

 of a muscle will increase its power to a certain 

 extent. 



(4.) The volition can be made to act on part 

 of the fibres of some muscles, as, for instance, 

 the gluteus medius, or the pectoralis major. 



(5.) The energy of a contracting muscle is 

 proportional to the energy of the volition. 



(6.) The firmness of a contracting muscle is 

 proportional to the energy with which it con- 

 tracts. 



