SPAVIN. 
123 
able become cemented and fixed together, and which is sometimes 
productive of caries of the articular surfaces of one or more of the 
joints of the hock. 
The Site OF Spavin is the antero -inferior part of the inner 
side of the hock, immediately beneath the prominence of the joint 
below. Why spavin should grow upon the inner , and never — or 
but very rarely indeed — upon the outer side of the hock, there are 
two satisfactory reasons : — one is, that the inner sides of the limbs 
are nearer to the central line of gravity than the outer ; the other, 
that, from the arrangement of the cuneiform bones, the hock joint is 
so constructed that the inner metatarsal bone is impressed by the 
superincumbent weight more forcibly, and consequently is com- 
pelled to yield or descend to a greater degree, than the outer bone. 
Such a phenomenon as a spavin on the outer side of the hock is all 
but unheard of : I am not saying it never occurs, nor indeed am I 
quite sure it would be called a spavin if it did : when any thing of 
the kind does happen, it is commonly the result of injury. Solley- 
sell mentions something of the kind, and calls it a jarde oi jar don. 
Spavins may . present themselves simultaneously in both hocks : 
commonly, but one hock is affected, and I do not know that either 
in this respect manifests any preference over its fellow. 
Causes of Spavin . 
These I shall consider under the heads of predisposing and ex- 
citing v 
Predisposition to Spavin may be either constitutional or 
local: in the former case, lying in breed or constitution ; in the latter 
in some peculiarity in the formation of the hock, or in the use made 
of it. Solleysell speaks of spavins being hereditary ; though 
Gibson’s interpretation of this is “ natural weakness.” In a paper 
from Mr. Carlisle, of Wigton, Cumberland, read before the Veteri- 
nary Medical Association, and published in The Veterinarian 
for 1839, the writer says — “ Hock diseases are often hereditary. I 
have known the progeny of some horses very much disposed 
to spavin ; others inherit a tendency to splents, ringbones, &c. 
The peculiar formation of the parts, inherited from the parent, 
render them susceptible of those diseases from causes that would 
make little impression on other horses.” 
For my own part I am very much disposed to believe in the ex- 
istence in the system of what I would call an ossific diathesis. I 
have most assuredly seen unbroke colts so prone in their economy 
to the production of bone, that, without any assignable outward 
cause — without recognisable injury of any kind — have, at a very 
early age, exhibited ringbones, and splents, and spavins. There 
