\ 



236 SYNOVIAL CAPSULES. 



the synovial membrane as passing over the face of the articular 

 cartilages ; it has however long been a question among anato- 

 mists and surgeons, whether such be really the case. It can 

 only be traced by the knife as far as the circumference of the 

 cartilages, nor can vessels by any means in the healthy state 

 be injected in it beyond this point. If it exist upon the carti- 

 lages, it is certainly so modifieq^ as not to be recognizable. It is 

 asserted by Mr. Toynbee* that it covers the cartilage as a 

 vascular membrane only in the early periods of foetal life and 

 that towards the period of birth the sub-synovial vessels, gradu- 

 ally recede from the surface of the articular cartilage and form 

 a zone around its margin ; a change somewhat like that which 

 takes place in the membrana pupillaris. I have several 

 minutely injected preparations of the joints taken from young 

 subjects, which show this zone of vessels, arranged in loops 

 somewhat like the mesenteric arches, around the beveled cir- 

 cumference of the cartilage, which are strongly confirmatory of 

 this opinion. But whether the synovial membrane recedes 

 with these vessels, or becomes so altered in character as to 

 form a smooth insensitive covering to the cartilage has not yet 

 been determined. An amputation at the knee joint which I 

 performed at the Philadelphia Hospital,f before the class of the 

 Jefferson Medical College, gave me an opportunity of observing 

 the changes daily, that are produced by morbid causes in the 

 cartilages of the joints. From the diseased condition of the 

 integuments of the leg, there was a scantiness of flap for cover- 

 ing the stump, which left the condyles partly exposed to view. 

 From round the margin of the cartilage and the place of 

 attachment of the crucial ligaments, in front of which the 

 synovial membrane passes, there was in the course of a fort- 

 night inflammation, secretion and a vigorous growth of granu- 

 lations. On the surface of the cartilage of the condyles there 

 appeared to be up to this time the slightest change ; it preserved 

 its polished shining aspect and was totally insensible to the 

 contact of an instrument. In the course of a few days more it 



* Memoir on the non vascular tissues, Phil. Trans. 1841. 

 f For the details of this case see Pancoast's Operative Surgery, 2d Edit. p. 

 169. 



