RADIO-ULNAR ARTICULATION. 



139 



and it separates the inferior radio-ulnar articulation from the wrist-joint. 

 The synovial membrane, sometimes called from its looseness membrana sacci- 

 formis, extends partly upwards between the 

 radius and ulna, partly horizontally inwards 

 between the ulna and triangular fibro-carti- 

 lage. When the fibro-cartilage is perforated, 

 as is occasionally the case, this synovial mem- 

 brane is continuous with that of the wrist- 

 joint. 



Fig. 128. THE LOWER PARTS OF THE RADIUS AND 

 ULNA, WITH THE TRIANGULAR FIBRO-CARTILAQE 



CONNECTING THEM. f 



1, ulna ; 2, its styloid process ; 3, radius ; 4, the 

 part of the articular surface for the scaphoid 

 bone ; 5, that for the semilunar bone ; 6, lower 

 surface of the triangular nbro-cartilage ; * *, a piece 

 of whalebone passed between the nbro-cartilage and 

 the ulna. 



Fig. 129. 



The interosseous mem- 

 brane or ligament of the 

 forearm is a thin, flat, 

 fibrous membrane, the 

 direction of whose fibres 

 is for the most part ob- 

 liquely downwards and 

 inwards, and which 

 extends between the 

 contiguous borders of 



Fig. 129. A, FRONT, AND 

 B, BACK VIEW OP THE 

 ARTICULATIONS OP THE 

 FOREARM, WRIST AND 

 HAND. 



1, the internal lateral 

 ligament of the elbow-joint; 

 2, the external lateral ; 3, 

 the anterior; 4, points to 

 the posterior ; 5, orbicular 

 ligament of the radius ; 6, 

 interosseous membrane ; 7, 

 oblique or round ligament ; 

 8, internal lateral ligament 

 of the wrist ; 9, external ; 

 10, anterior; 11, posterior; 

 12, palmar, and 13, dorsal 

 carpo - metacarpal liga- 

 ments ; 14, ligaments con- 

 necting metacarpal bones ; 

 15, transverse metacarpal 

 ligament ; 16, carpo- meta- 

 carpal ligament of the 

 thumb ; 17, lateral liga- 

 ments connecting the pha- 

 langeal with the metacarpal 

 bones; 18, lateral liga- 

 ments of the phalanges. 



