ON SPLINTS. 
541 
Now, having shewn, in some degree, why I should have come 
to this conclusion, of the weight being sent down the anterior 
part of the carpus, I shall follow the remainder of its effects 
upon the other bones. 
The pressure having caused the os unciforme and os magnum, 
which are bound together on their anterior part by a horizontal 
ligament about an inch in length, to divide, and that most ante¬ 
riorly, it will follow that these bones will describe a portion of a 
circle. 
This being the result, the larger circumference moving most, 
that of the os unciforme acts on the outer small metacarpal 
bone(g^, on an inclined plane upwards ; while that of the os 
magnum acts with the os trapezoides (A), and the head of the 
inner metacarpal bone (i), which articulates with them in a per¬ 
pendicular position. 
When either of these two bones are moved beyond their pro¬ 
per limits, they will press distinctly on the anterior part of the 
small metacarpal bones. The small metacarpal bones are united 
to the large ones by ligamentous fibres crossing each other like 
an X, the outer metacarpal bones having in front, at the supe¬ 
rior part, about one-eighth of an inch of the ligament interposed, 
but not so much posteriorly. Two inches and a half below the 
head, the two bones come nearly in contact, and continue in 
that close connexion from two to three inches downwards, and 
then they are set at liberty for another purpose,—that of giving 
attachment, by their rounded extremities, to ligaments which 
support the small portion of horn at the back part of the fetlock. 
The inner metacarpal bones vary as to their distance from the 
larger, the space at the superior part of the ligamentous sub¬ 
stance being three-eighths of an inch ; and they also approach 
each other three inches lower down. I may here observe, that 
their ligamentous union posteriorly is more uniform. 
At some length I have treated of the physiology of the parts 
which, I imagine, have the greatest share in producing splints. 
The causes of splint are various, but they may frequently be 
traced to abuse of the horse, or to ignorance. When an out¬ 
side heel is turned on a shoe, and none on the inside, a splint 
will usually be the result. 
It is likewise an acknowledged fact, that horses that turn 
their toes inward are also liable to splints on the outside of the 
limb : when the toes are reversed, they are formed on the inside 
of the leg. It may also be stated, that when the toes are turned 
inwards the knees are thrown outwards ; while, when the con¬ 
trary is the case, the knees approximate. In this instance the 
outside of the shoe wears most; and, as a consequence, the chief 
VOL. VI. 4 A 
