OP THE ARTICULATE CARTILAGES. 351 



truth, greatly resembles that of the diarthrodial cartilages. In 

 the natural diarthrodial articulations, the destruction of the 

 cartilages is sometimes followed by their nearly perfect re- 

 production ; only the new cartilage produced at the surface of 

 the bone, being thinner, has a somewhat bluish appearance, 

 which is owing to its semi-transparency. The edges of the 

 old cartilage are free, and extend over the very thin contour of 

 the new cartilage. 



In the joints of old persons affected with various other al- 

 terations, the diarthrodial cartilages are sometimes found con- 

 verted into villous fibres, free and floating. When laid bare 

 in amputation at the joints, if the wound unites by first inten- 

 tion, the cartilage and its synovial membrane do not unite, 

 but remain free behind the cicatrix. If the wound remains 

 open, if it inflames and suppurates, the cartilage is seen at the 

 end of some days to soften, and afterwards gradually to disap- 

 pear from the circumference to the centre, in proportion as 

 the granulations extend to the surface of the bone, and even 

 before they reach it. Inflammation of the diarthrodial carti- 

 lages is in general of rare occurrence; and, when it takes 

 place, commonly terminates by ulceration or absorption. This 

 ulceration of the diarthrodial cartilages is most commonly 

 consequent to inflammation of the synovial membrane or bone, 

 sometimes to that of the cartilage itself, but it also sometimes 

 seems not to be preceded by any inflammation. Sometimes, 

 before ulcerating, the cartilage softens and assumes a fibrous 

 appearance. This ulceration most commonly takes place in 

 young subjects, or before middle age. It is accompanied by 

 a pain, which is at first slight, but which gradually increases 

 in intensity. When the ulceration stops and heals, there 

 takes place a reproduction of cartilage, of which we have al- 

 ready spoken, or a bony production of the nature of ivory 

 or enamel, or, lastly, a union of the surfaces by anchylosis. 

 In the case of true anchylosis, the cartilages are always ab- 

 sorbed. 



557. The cartilages of the synarthrodial articulations, are 

 extremely thin laminae, placed between the bones which are 

 articulated in an immoveable manner, and holding firmly on 



