

ARTICULATIONS. 



terior aspects of the internal condyle, and below to the inner 

 margin of the great sigmoid cavity. The anterior band goes to 

 the inner margin of the coronoid process, the posterior band to 

 that of the olecranon, and the weak intermediate fibres to a 

 transverse band \vhich connects the inner margins of the coro- 

 noid and olecranon processes. The external lateral is a flat 

 band attached above to the back and lower part of the exter- 

 nal condyle, and blending below with the orbicular ligament 

 of the superior radio-ulna! joint. [280] 



Pads of fat lie within the capsule in front of the coronoid 

 and supracapitellar fossa 1 , and projecting toward the olecranon 

 fossa. The synovial membrane lines the capsule, fat pads, and 

 the enclosed bone which is not covered by cartilage, especially 

 the radial neck; the elbow and superior radio-ulnar joints 

 have a common cavity. [281] 



Superior Radio-ulnar Joint. This is a lateral ginglymus be- 

 tween the lesser sigmoid cavity of the ulna and the side of the 

 head of the radius. Its synovial membrane is continuous with 

 that of the elbow joint. The special feature is the orbicular 

 ligament, a broad band which forms four-fifths of a circle and 

 is attached by its ends to the anterior and posterior margins 

 of the lesser sigmoid cavity ; it encircles the head of the radius 

 and is widest above. [281] 



Inferior Radio-ulnar Joint. This is a lateral ginglymus be- 

 tween the side of the head of the ulna and the sigmoid cavity 

 of the radius ; it includes the lower end of the head of the ulna, 

 which articulates with the fibro-cartilage. The triangular inter- 

 articular fibro-cartilage is attached by its apex to the depression 

 on the outer side of the root of the ulnar styloid process, and by 

 its base to the edge between the sigmoid cavity and carpal sur- 

 face of the radius, binding them together; it helps form two 

 joints. The capsule is imperfect and consists of transverse 

 fibres (anterior and posterior radio-ulnar ligaments) connecting 

 the bones in front and behind. A synovial membrane com- 

 pletes the cavity, covers the fibro-cartilage, and sends a diver- 



[153] 



