Hatcher: Fore I.nir, anh Mams i>i IIkon i i l-^ \i ki 



;}C)5 



end of this rugosity it is interrupted by a deep groove which starts on 

 the inner side, runs oblitpiely downward and outward, completely 



Kic. 5. Distal ends of right radius 

 and ulna in position, about one-tenth 

 natural size. (No. 563.) 



Vu;. 6. Proximal end of right ra- 

 dins and ulna in position, about one- 

 tenth natural size. (No. 563). 



bisecting the rugosity. This groove doubtless served for the trans- 

 mission of an artery. Opposed to this rugosity on the radius there is 

 a similar one on the middle of the internal 

 surface of the ulna near its distal extremity. 

 These rugosities doubtless served for the attach- 

 ment of the muscles which held these bones 

 in place. Seen from below, the articular sur- 

 face of the distal end of the radius has the form 

 of an elongated ellipse with an area somewhat 

 e.xceeding that of the distal end of the ulna, 

 which takes the form of an oblique quadrangle 

 with its two axes nearly equal. There is on 

 the internal surface of the distal end of the ulna 

 a rather deep emargination or fossa for the re- 

 ception of the rounded postero-external angle 

 of the distal end of the radius. This emargi- 

 nation appears, though less distinctly, on the 

 internal border of the distal articular surface of 

 the ulna, as shown in Fig. 5. Its presence 

 affords great assistance in the proper adjust- 

 ment of these bones, since when they are so 

 placed that the convex siu-face of the proximal 

 end of the radius fits nicely into the radial 

 groove of the ulna and the ])ostero-external 

 angle of the distal end of the radius in this fossa 

 there can be no question as to the correct rela- 

 tive positions of these bones. The articular surfaces of the distal ends 



¥lG. 7. Posterior 

 view of right radius, 

 about one-tenth natural 

 size. (No. 563.) 



