’38 
MANUAL OF MODERN FARRIERY. 
strain, and especially those oi the hock, which increases the 
tendency to spavin. 
It is this which induces in the first instance inflammation 
of the cartilaginous union of the shank-bone, and this 
cartilage is absorbed, and a secretion of bony substance 
deposited in its stead ; consequently the elastic action 
between them is terminated, and the splint inside the hind 
leg formed, and has the appearance of a tumour, when the 
head of the splint-bone is united with the shank, and always 
in front of that junction, as exhibited in plate 7, fig. 3, c. 
Lameness universally accompanies spavin, but when the 
periosteum or membrane of the bone has been stretched, 
and taken the form of the bony enlargement, then the pain 
subsides, and with it the lameness. This, however, depends 
upon the size of the spavin, and whether it interferes with 
the motion of the joint. Many instances occur of horses 
with large spavins, and yet they are not much afflicted with 
lameness ; sometimes having merely a stiffness of the joint, 
which is not apparent after the animal has had a little 
exercise. And, on the contrary, there are instances in 
which the bony deposit is very small, and yet the horse is 
very lame, so much so as to render him comparatively 
useless. It must therefore be evident that we ought care¬ 
fully to examine horses with spavin before they have had 
exercise, and as soon as they have left the stable. 
Sometimes spavin continues to enlarge considerably, and 
spreads over the lower wedge-bones, (plate 7, fig. 8, e.) in 
consequence of these being nearest the original seat of the 
enlargement. These bones are capable of a small degree 
of motion, and participate in every action of the joint, but 
their chief office is to prevent concussion. The principal 
motion of the joint is in the tibia, b, and the astragalus, 
c, and consequently stiffness more than lameness may 
