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.+ 
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 corone, so with 
this exact diagnosis is difficuli—we may say almost impos- 
sible. 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 8rd Hussars (G. 15). On November 22, 1881, 
on the march from Norwich to Aldershot, the horse suddenly 
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 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 Mr. Stanley, M.R.C.V.S., of Edmonton, who pronounced 
it a case of navicular disease. I first saw the animal on 
* Veterinary Journal, vol. xxxi., p. 246. 
t+ Veterinarian for 1857, p. 73. 
