DISEASES OF THE JOINTS 417 



(b) Purulent or Suppurative Synovitis. 

 In this condition we have synovitis complicated by the 

 presence of pus. Unlike the simple form, it shows a marked 

 disposition to spread, and quickly involves the surrounding 

 structures. Very soon the ligaments of the joint, the peri- 

 osteum, the articular cartilages, and the bones are impli- 

 cated. This, of course, constitutes a condition of acute 

 purulent arthritis. Under that heading, therefore, the con- 

 dition will be later discussed. 



B. AETHRITIS. 

 {a) Simple or Serous Arthritis. 

 With an attack of simple synovitis it may be always 

 assumed that the changes commenced in the synovial mem- 

 brane, communicate themselves more or less readily to the 

 surrounding tissues, and are not confined to the synovial 

 membrane alone. We may thus have the inflammatory 

 phenomena asserting themselves in the surrounding liga- 

 ments, in the periosteum, in the bone, and in the articular 

 cartilages. It depends, in fact, upon the severity of our 

 case whether we call it synovitis or arthritis. The two 

 conditions merge so the one into the other that no hard- 

 and-fast rule may be laid down whereby they may with 

 certainty be differentiated. Such symptoms, therefore, as 

 we have given for synovitis may be also read as indicating 

 a condition of simple arthritis. The course of the case will 

 be very similar, and the treatment to be followed identical 

 with that just given. 



(b) Acute Arthritis. 



Causes. — An attack of acute arthritis may commence with 

 the affection of the synovial membrane, and spread from 

 that to the other structures. In other cases the disease of 

 the synovial membrane, and after it the disease of the joint, 

 may be secondary to diseases commencing in the structures 

 around the joint. This affection may therefore follow on a 



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