h at the level of the navicular bone. There was
slight evidence of navicular disease. The articular cartilage of the
corono-pedal joint had been almost completely removed, and there was
sclerosis of the opposed bony surfaces, which by unequal wear had brought
about deformity of the os coronae and os pedis.

There was very old-standing fracture of the pyramidal process (see Fig.
157), with the formation of a false joint between the process and the pedal
bone. There was also a recent fracture of the part of the pedal bone which
carries the articulation for the navicular bone, and this and the tendon
lesions probably accounted for the final symptoms of 'break-down.'

Neurectomy enabled us to get a year's useful work out of what would
otherwise have been a hopeless cripple.[A]

[Footnote A: A.R. Routledge, M.R.C.V.S., _Journal of Comparative Pathology
and Therapeutics_, vol. xvi., p. 371.]

C. FRACTURES OF THE BONES.

More or less by reason of the protection afforded them by the hoof
fractures of the bones of the foot are rare. When occurring they are more
often than not the result of direct injury, as, for example, violent blows,
the trapping of the foot in railway points, the running over of the foot
with a heavily-laden waggon, or violent kicking against a gate or a wall.
They occur also as a result of an uneven step upon a loose stone when going
at a fast pace, and as a result of sudden slips and turns, in which latter
case they are met with when animals have been galloping unrestrained in
a field, or when an animal, ridden or driven at a fast pace, is suddenly
pulled up, or just as suddenly turned.

At other times fractures in this region take place without ascertainable
cause, and cases are on record where animals turned overnight into a
loose box in their usual sound condition have been found in the morning
excessively lame, and fracture afterwards diagnosed.

1. FRACTURES OF THE OS CORONAE.

Fractures of the os coronae result from such causes as we have just
enumerated, and are nearly always seen in conjunction with fractured
os suffraginis. When this latter bone is also fractured diagnosis is
comparatively easy, a certain amount of crepitus, even when the suffraginis
is only split, being obtainable. When the os corona alone is fractured
then diagnosis is extremely difficult, the smallness of the bone and the
comparative rigidity of the parts rendering manipulation almost useless,
and effectually preventin