108 LAMENESS OF THE HORSE 



tion of the periosteum at the site of the interosseous ligament 

 which attaches the small to the large metacarpal bone. This liga- 

 ment is involved in the inflammatory process, and according to 

 Havemann, whose view is supported by Moller, this inflamma- 

 tion is the origin of the trouble. 



Various theories attempting an explanation of the frequent 

 affection of this one certain part so regularly involved have been 

 offered, but no proof of the correctness of any exists. It fol- 

 lows, however, that splints occur in young animals; that the 

 affection seldom starts in subjects that are ten years of age or 



""-■'-isliC J- 



Fig'. 16 — Posterior view of radius (rigiit) illustrative of effects of splint. 

 Note the extent of exostosis. 



older, and that when the exostosis has formed, lameness usually 

 subsides. Anything which will cause undue strain or irritation 

 of the metacarpal bones in young animals, is quite apt to result 

 in a splint being formed. Concussion such as is caused by fast 

 work on hard roads, or work on rough or irregular road surfaces 

 which cause unequal distribution of weight, will cause splint 

 lameness and exostosis follows. 



Course. — Because of the peculiar manner in which the second 

 and third metacarpal bones articulate in j^oung animals, until 

 the bones become ossified and permanently joined, the inflam- 

 mation which attends the acute stage of this affection, causes 

 lameness. Later, unless an unusually large exostosis is formed, 

 whicli may cause a constant irritation due to its size and juxta- 

 position to the carpus, lameness is disconlinued. 



