SPLINT. 309 



interosseous ligaments ; and those which arise from irritation and inflam- 

 mation of the periosteum or of the bone itself. But for practical pur- 

 poses it is not necessary to maintain this distinction. Indeed, whichever 

 structure be primarily affected, the other also generally becomes more or 

 less involved. 



616. Mode of formation of Splint. 



When inflammation is set up in a bone or in its periosteum, an exos- 

 tosis is likely to be the result, unless the action is checked in the very 

 early stage. The mode in which osseous material is effused and consoli- 

 dated was explained in Chapter 35, par. 581-2. The exostosis or " Splint " 

 will probably unite firmly the small to the great metacarpal bone. 



Again, if the inflammation is set up in the interosseous ligaments, it 

 generally results in absorption of the original tissue to a greater or less 

 degree according to circumstances; and in lieu thereof osseous material 

 is deposited, which, when in due time consolidated, unites together the 

 bones between which it is effused. The cause of this peculiar effect of 

 inflammation on fibro-cartilage, of which tissue the interosseous ligaments 

 are mainly composed, is not well ascertained ; but its almost invariable 

 occurrence is a well-known fact. 



617. Causes of Splint. 



Though the immediate causes of Splint are irritation and inflammation 

 in the parts affected, yet the occurrence of these causes in any particular 

 horse and at any particular time is mainly dependent on the conformation 

 of the leg, on the work to which the animal is subjected, on the weight 

 he has to carry, and on his age. 



If the bones of the leg are small, or if not positively so, are yet small 

 in reference to the carcass ; or if there is undue length between the knee 

 and the fetlock; or if the ligaments and tendons are small, or if the 

 legs are crooked, we may be pretty sure that such defects of conformation 

 will probably give rise to irritation and inflammation in the weakest 

 part. 



Again if the pasterns are over-long, there will be undue stress on the 

 parts above ; or if on the other hand they are very short, there will be ex- 

 cessive concussion. These effects, though arising from defective con- 

 formation below, may nevertheless be felt above, notwithstanding the 

 portion of the leg from the fetlock to the knee may be well formed. 



Again, if the legs are not placed well and directly under the centre of 

 gravity, or if the incidence of the weight of the body does not fall fair 

 and true on the legs, there will be irritation and inflammation in the 

 part unduly pressed upon. Plate 26. 



But no cause of Splint is perhaps more common than the ordinary 

 practice of subjecting young horses to work for which (however good 

 their make and shape may be) their young bones, ligaments and tendons 

 are unfit. Farmers, who breed horses, generally put them to harrow 

 at two years old, they often ride or drive them at three, and hunting 



