ARTICULATIONS AND LIGAMENTS. 



123 



of ulna. Its synovial cavity communicates with the elbow- joint 

 and it is held together by the orbicular, or annular ligament, at- 

 tached in front and behind to the lesser sigmoid cavity and sur- 

 rounding the head of radius. Its arteries and nerves are the 

 same as for elbow. 



The middle radio-ulnar articulation consists of the oblique 

 or round ligament, passing from tubercle of ulna to below 

 tuberosity of radius, and the interosseous passing between the 

 bones, deficient above for passage of posterior interosseous ves- 



FlG 91. 



1, anterior ligament; 2 and 2, anterior and posterior portions of 

 Internal lateral; 3, orbicular ligament; 4, oblique; 5, interosseous 

 membrane. 



sels, and perforated below for anterior vessels. Its arteries are 

 from anterior interosseous; its nerves, from anterior and pos- 

 terior interosseous. 



Inferior radio-ulnar consists of anterior and posterior radio- 

 ulnar ligaments, passing from one to the other in front and back 

 of wrist, and triangular interarticular fibro-cartilage, interposed 

 between head of ulna and cuneiform bone, and binding the radius 

 and ulna firmly together. Its art eric* ;nv from anterior and 

 posterior interosseous and carpal; its nerves, from median and 

 posterior interosseous. 



