2 2 THE PRIXCIPLES OF MYODYXAMICS. 



(3.) The radius acted on by the biceps brachii 

 is a lever of the third order. 



14. According to the direction of their fibres, 

 muscles are of three kinds : direct, oblique, and 

 radiate. 



( I .) In a direct fibred muscle the fibres run in a 

 longitudinal direction from the tendon of origin to 

 the tendon of insertion, as is shown in I. Fig. 4. 



(2.) In an oblique fibred muscle the fibres run 

 in an oblique direction from the tendon of origin 

 to the tendon of insertion, as is shown in II, III, 

 IV, Fig. 4. 



There are three kinds of oblique fibred mus- 

 cles : The short oblique (II), the long oblique 

 (III), and the double obliqite (IV). 



(3.) In the radiate fibred muscle the fibres run 

 in radiate directions from a central tendon to 

 various points of insertion (\"). 



Examples : — 



(i.) The sartorius is a direct fibred muscle. 



(ii.) The extensor proprius pollicis is a short 

 oblique fibred muscle. 



(iii.) The semimembranosus is a long oblique 

 fibred muscle. 



