436 Diseases of Joints. 



the Joint. — Left knee of an adult — injected and in spirit, 

 laid open by turning up the patella, illustrating the above. 



The articular cartilages have been attacked round the 

 margins here and there, especially upon the inner condyle, 

 the outer part of the trochlear surface of the femur, and on the 

 patella. The bone in these places is exposed, and the cartilage 

 either removed entirely or partly detached. The synovial 

 membrane is involved all round, and two sinuses, one above 

 either condyle, communicate between the joint and the skin. 

 The femur is thickened by a deposit of new periosteal bone 

 round the shaft. F. P. C. 2965. 



7. 27. Abscess extending- from Tubercular Synovitis.— 



Section of the lower end of a left femur, with part of the wall 

 of an abscess above the articular surface — in spirit. 



Probably this has been a tubercular extension into the 

 bursa under the subcrureus. B. C. ii. M. 22. 



7. 28. Tubercular Synovitis, with Abscesses and Destruc- 

 tion of Cartilag'e. — Eight knee-joint of a child — injected 

 with vermilion, laid open from the front — in spirit, illustrating 

 the above. 



The articular cartilage of the femur has been entirely 

 destroyed, except upon a narrow area round the edge. The 

 trochlear surface and that of the inner condyle is covered with 

 granulations, and the under surface of the outer condyle is 

 irregularly hollowed out. On the outer aspect of the femur the 

 walls of an abscess cavity are shown communicating in two 

 places with the interior of the joint, as well as with another 

 abscess beneath the subcrureus muscle. 



This illustrates the mode of formation of these abscesses. 

 Portions of the thickened, gelatinous, synovial membrane 

 caseate, soften, and run together to form an abscess. This 



