ARTICULAR CARTILAGES. 255 



OF THE ARTICULAR CARTILAGES. 



To this class we refer, exclusively, such as adhere by one 

 surface to the articular facings of the bones, and present the 

 other surface to the cavity of the joint. Every moveable, and 

 some of the immoveable articulations, have their surface uni- 

 formly thus incrusted, to a thickness varying from the fraction 

 of a line in the smallest joints, to one line in the largest. The 

 cartilage itself is rather thinner near the margin of the articular 

 surface, when the latter is convex, than it is near the centre; 

 on the contrary, when the surface is concave, the cartilage is 

 thickest near its periphery. 



These cartilages, when subjected to a maceration of six 

 months, are stripped of the reflection of synovial membrane, 

 which covers their articular surfaces, and are resolved into 

 fibres, one end of which adheres to the bone and the other end 

 points to the joint. If the preparation be then dried, the dis- 

 tinction of fibres becomes more manifest. 



The most successful injections, closely examined with a mi- 

 croscope, demonstrate the defect of blood vessels in them. The 

 vessels are uniformly seen to terminate at the circumference of 

 the cartilage and at the face which adheres to the bone, but 

 never to penetrate it. Their organization is, therefore, ex- 

 tremely simple, and such as subjects them to but few morbid 

 alterations. When partially removed from the bone the latter 

 occasionally reproduces them, but the edges of the new and of 

 the old production do not unite. I have, in cases of inflamma- 

 tion of the joints, seen the fibres of these cartilages much longer 

 than usual and detached from each other. When a joint is 

 laid open by a wound, and suppurates, the cartilage softens 

 and disappears from the circumference to the centre.* 



* Bichat, Anat. Gen. The same author speaks of the idiopathic ulceration of 

 the cartilage, as a result of its inflammation. The late Dr. Physick, whose ex- 

 perience is equal, denies both. 



