DISEASES AFFECTING FEET 



is not constant. The author's experience is insuiftcient to 

 enable him to speak with confidence upon its point of origin, but 

 a very tenable view is that the disease has its starting point upon 

 the gliding surface (under surface) of the navicular bone. It is 

 quite possible that the inflammation is of a rheumatic nature in 

 some instances, but its occurrence through injury is against 

 this theory as to the sole cause. 



Disease of the ghding surface of the navicular bone will 

 soon be followed by disease of the tendon, over which the latter 

 glides. Brown spots of minute size are found upon the cartilage 

 (gristle) covering this gliding (lower) surface of the bone, sub- 

 sequently the cartilage becomes rough, and has an eroded 

 (eaten) appearance. In course of time the disease advances 

 into the substance of the bone, although it has been said that 

 such may precede the changes in the cartilage, covering the 

 surface previously alluded to. The tendon is always diseased 

 upon its surface ghding over the bone, and sometimes fixed to 

 this latter. The first change observable consists in the forma- 

 tion of rusty coloured spots, and it then becomes roughened. If 

 the eroding process goes on and on, some of the minute fibres of 

 the tendon are torn, until perhaps this latter completely gives way. 

 When the sheath (bursa) is inflamed, it appears thickened, or even 

 blood-red. 



Causes. — It has long been supposed that navicular disease 

 is hereditary, but this is, probably, only true as regards 

 peculiarity of conformation in connection with the feet. It almost 

 always affects the fore feet, and usually the lighter breeds, 

 especially quick movers with high action. The explanation of 

 its almost constant occurrence in the fore feet appears to be 

 that there is a greater degree of concussion here than in the 

 hind feet. 



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