BONE SPAVIN. 459 
will sometimes do wonders in recent cases. The scarification should be 
repeated at intervals of five or six days, taking care to avoid injury to the 
coronary substance near the hoofs, which is sometimes followed by trouble- 
some sores. 
BONE SPAVIN. 
THIS DISEASE, so frequently the cause of lameness in those horses which 
use their hocks severely (as for example race horses, hunters, carriage 
horses, and more particularly cart horses), consists in exostosis from 
the adjacent external surfaces of the tarsal bones, always showing 
itself at the inner side of the hock joint, on the scaphoid and cunei- 
form bones, and extending to the head of the internal small meta- 
tarsal bone. As in the case of splint, the occurrence of exostosis on 
the internal rather than on the 
external side of the hock has been 
accounted for by the supposition 
that increased weight is thrown 
upon the internal small metatarsal 
bone, from the turning up of the 
outer heel of the shoe, which is the 
common practice of smiths. It 
appears to me, however, that the 
contrary is the case, and that though 
more stress is laid upon the foot on 
that side, there is less weight on 
the inner side of the hock, which 
has a tendency to spring open in 
that direction. This will cause a 
-strain upon the ligaments connect- 
ing the tarsal bones, and nature 
coming to their aid throws out bone, 
which ultimately substitutes anchy- 
losis for ligamentous union between 
these bones. In all the actions of 
the hind leg, from the natural shape 
of the hock, and.more especiaily 
in those horses which are naturally 
“cow-hocked,” there is a tendency 
to yield inwards rather than in the Fic. 5.—ANTERO-INTERNAL VIEW OF HXOSTOSIS 
opposite direction. The consequence CONSTITUTING SPAVIN. 
is that there is more strain upon the 1. Os scaphoides. 
ligamentous fibres which connect 3 Yomia Eoanonnens constituting the disease 
the scaphoid with the two cuneiform known as bone spavin. 
and the internal metatarsal, than Sarl ie ee aise ware 
upon those uniting the cuboid with the os calcis and external metatarsal 
bone. Hence, although exostosis does sometimes show itself in other 
parts of the tarsal bones, it here, as in the fore leg, is almost always 
confined to what is called the “spavin place,” namely, the contiguous 
surfaces of the scaphoid, cuneiform, and internal metatarsal bones. In 
very bad cases the articular cartilage becomes involved, and there is not 
only an external casing of new bone, but the internal surfaces absolutely 
coalesce or anchylose. 
Tur symproms of spavin are a hard substance showing itself beyond 
the proper level of the hock joint, at the spot which is pointed out in 
