68 THE PRI^XIPLES OF MVODVXAMICS. 



[2.) The outward turn of the radius is called 

 oiit-rotatioji. 



(3.) The arc of rotation of the radius is about 

 180 decrees. 



52. When the fore-arm is completely ex- 

 tended the long; axis of the ulna is nearly on a 

 line with the long axis of the humerus. 



(i.) Completely siipinatc the radius and the 

 lonof axis of the fore-arm and the lono^ axis of 

 the humerus will meet forming an obtuse angle 

 on the outside. 



(2.) Com.pletely pronate the radius and the 

 long axis of the fore-arm will be quite on a line 

 with the lono^ axis of the humerus. 



(3.) During the rotation of the radius a line 

 drawn from the point of the styloid process to 

 the upper end of the axis of the radial head will 

 describe one-half of a cone : This may be called 

 the radial cone. 



53. The following dimensions of the radial 

 cone were taken in a given case : — 



(i.) The radius of the base of the radial cone 

 was about one and three-fourths inches in 

 length. 



