/O THE PRI^XIPLES OF MVODYNAMICS. 



a vertical line in the plane of the fore-arm at an 

 angle of about 135 degrees. 



56. The muscles that rotate the fore -arm are 

 divided into two groups : — The pronators and 

 the sitpinators : — 



(i.) The pronators of the fore-arm are — the 

 pronator qitadratns. the pronator radii teres, the 

 supinator longus, the biceps brachii, the flexor 

 carpi radialis, the flexor sublimis digitorum, and 

 the flexor profundus digitorum. 



(2.) The supinators of the fore-arm are — The 

 stLpinator brevis, the extensor ossis inetacarpi pol- 

 licis, the extensor primi inter nodii pollicis, the 

 extensor seenndi internodii pollicis, the supinator 

 longus, the extensor carpi radialis langior, and 

 the biceps brachii. 



57. The supinator longus has three func- 

 tions : — 



(i.) It flexes the radius; (2.) it pronates the 

 radius during the first part of in-rotation ; (3.) it 

 supinates the radius during the first part of out- 

 rotation. 



58. A muscle whose long axis runs in the 

 direction of the diagonal of the quadrangle of 



