290 SKELETON. 



is brought more distinctly into view by cutting open the joint. It 

 is then seen to arise from the anterior margin of the lesser sig- 

 moid cavity of the ulna, and surrounding two-thirds of the neck 

 of the radius, to be inserted into the posterior margin of the same 

 cavity. Jtis a strong, flat, narrow fasciculus, the fibres of which 

 go in a circular direction. Its superior margin is blended with the 

 external lateral ligament; its inferior margin fs loose, being con- 

 nected with the lower part of the neck of the radius only by a 

 reflection of the synovial membrane, with the exception that a 

 few fibres pass from it behind, to the contiguous part of the ulna. 

 Its density is very considerable, sometimes almost cartilaginous. 



The Synovial Membrane lines the whole internal face of the 

 capsular ligament, from which it is separated behind by a large 

 mass of fat in the olecranon depression of the os humeri, and in 

 front by another mass in the coronoid depression. A small 

 circular ridge of fat also projects into the joint around the head 

 of the radius, and there is another at the internal margin of the 

 olecranon. The object of these masses seems to be to fill up 

 the partial vacancies which exist between the articular faces 

 of the bones, and they are all so directed by their attachment 

 to the capsular ligament, as to be preserved from being pinched. 

 The synovial membrane is also reflected from the capsular li- 

 gament to the articular faces of the bones, so as to line the se- 

 veral depressions on the os humeri, and to include the neck of 

 the radius. 



The head of the radius is completely invested with cartilage. 

 The greater sigmoid cavity of the ulna has the cartilage sepa- 

 rated transversely into two portions, by a small mass of fat 

 traversing its bottom. The cartilage elsewhere is uniformly 

 spread over the articular surfaces of the bones. 



Of the Literosseal Ligament, (Membrana Interossea.} It fills 

 up the space between the two bones of the fore arm almost en- 

 tirely, by commencing just below the tubercle of the radius 

 and ending near the wrist. It consists in oblique and parallel 

 fibres, which pass from the ulnar edge of the radius downwards 

 to the radial edge of the ulna. It is thin, but extremely strong, 

 bein^ covered in front by the flexor muscles; and behind by the 



