DISEASES OF THE BONES 409 



that of stabs or deep pricks in the region of the point of the 

 frog (see p. 216). Following that, the next most common 

 cause is violent injury. We thus find the navicular bone 

 fractured, together with one or both of the other bones of 

 the foot, when the foot is run over by a heavy vehicle. One 

 such case is reported by Mr. J. H. Carter, F.R.C.V.S., where 

 the horse's foot was run over by a tram-engine, in which the 

 os pedis and the navicular were fractured in several places.* 

 A further case is on record where a sharp blow on the front 

 of the hoof was the cause. In this case the os pedis and 

 other structures were uninjured, but the navicular bone was 

 fractured into three large, and about half a dozen small 

 pieces, t 



Fractures of the navicular may occur, however, in which 

 history of a prick or of a violent injury is absent. See 

 reported case below. 



As with fractures of the os pedis and the os coronse, so 

 with this exact diagnosis is difficult — we may say almost im- 

 possible. With a history of violent injury, however, some 

 little regard may be paid to a continued heat and tenderness 

 of the foot, and a distinct inclination on the part of the 

 animal to go on the toe. Even when the fracture is the 

 result of a prick, and the bone is plainly felt with the probe, 

 we still cannot be positive as to fracture. 



Reported Case. — ' The animal was a Hungarian, a troop- 

 horse in the 3rd Hussars ( G. 15). On November 22, 1881. 

 on the march from Norwich to Aldershot, the horse sud- 

 denly made a violent stumble, very nearly coming on to his 

 knees. The rider declared that he put his foot on a stone. 

 The accident caused great lameness in the near fore-leg, and 

 and the horse had to be led the remainder of that day's 

 march. On the following day he was also led ; but, after 

 going some sixteen or eighteen miles, he was so lame that he 

 was left at the nearest billet (in Edmonton). He was here 

 attended by Air. Stanley, M.R.C.V.S., of Edmonton, who 

 pronounced it a case of navicular disease. I first saw the 



* Veterinary Journal, vol. xxxi., p. 246. 

 t Veterinarian for 1857, p. ~3. 



