200 PEmOIPLES OP VETEBINAKT SUEGEBT 



started in the hyaline cartilage of the articular cartilagSy 

 gradually extending to these structures. 



What are the terminations of arthritis deformans f 



The pathological changes just described either advance ta 

 such an extent that the joint becomes useless or a more favor- 

 able termination sets in by synosteosis. 



How does arthritis deformans terminate favorably by synoste- 

 osis f 

 To begin with, this only occurs in joints with limited 

 motion, as in the tarsus and carpus. The favorable termina- 

 tion lies in the fact that the articular surfaces, bared of their 

 hyaline cartilage by the diseased process, become fused — that 

 is, anchylosed. In such joints as the hip or stifle the fre& 

 motion prohibits anchylosis ; such animals therefore remain- 

 ing cripples. 



What articulations are mainly exposed to arthritis defor- 

 mans ? 

 In the horse, the hock joint, where the exostosis is known, 

 as spavin ; the carpus, the stifle joint, the hip, the latter espe- 

 cially in the dog, cattle and more rarely in the horse. 



Js the spavin always the result of a true arthritis chronica- 

 deformans 9 



To be the result of a true chronic deforming arthritis, the- 

 pathological lesion must start in the articular cartilage of a. 

 joint. No doubt some spavins take their origin from this 

 point. The classical histological studies by Gotti at the 

 same time show that in many spavins the primary pathologi- 

 cal lesions originate in the osseous tissue, and as the result of 

 this primary osteitis a secondary chronic def oi-ming arthritis 

 sets in. This happens as follows : At first there is an osteitis: 



