BONE SPAVIN. 389 



in a veiy slight degree on the shank-bone, but principally or almost 

 entirely on the inner splint-bone. Then the splint-bones sustain a very 

 unequal degree of concussion and weight. Not only is the inner one 

 placed more under the body and nearer the centre of gra\nt3'-, but it has 

 almost the whole of the weight and concussion communicated to the 

 Bmaller cuneiform bone carried on to it. It is not, therefore, to be won- 

 dered at, that in the violent action of this joint in galloping, leaping, 

 hea^'y draught, and especially in young horses, and before the limbs 

 have become properly knit, the inner splint-bone or its ligaments, or the 

 (substance which connects it with the shank-bone, should suffer material 

 ijijury. 



The smith increases the tendency to this by his injudicious management 

 of the feet. It is a common notion that cutting, and wounds in the feet 

 — from one foot treading on the other — are prevented by putting on a 

 shoe with a calkin on the outer heel, that is, the extremity of the heel 

 being considerably raised from the ground. It is not unusual to see 

 whole teams of horses with the outer heel of the hind foot considerably 

 raised above the other. This unequal bearmg, or distribution of the 

 weight, cannot fail of being injurious. It places an unequal strain on the 

 ligaments of the joints, and particularly of the hock -joint, and increases 

 the tendency to spavin. It, should, therefore, be considered as an axiom, 

 that whenever it is necessary, in order to give the animal a firmer hold 

 or footing — to turn up or caulk the outside heel of the shoe, the inside 

 should invariably be thickened to an eqiial extent. 



The weight and concussion thus thrown on the inner splint-bone pro- 

 duce inflammation of the cartilaginous substance that unites it to the 

 shank-bone. In consequence of it, the cartilage is absorbed, and bone 

 deposited ; the union between the splint-bone and the shank becomes 

 bony, instead of cartilaginous ; the degree of elastic action between them 

 is destroyed, and there is formed a splint of the hind leg. This is uni- 

 formly on the inside of the hind leg, because the greatest weight and 

 concussion are thi'own on the in.ner splint-bones. As in the fore leo-, 

 the disposition to form bony matter having commenced, and the cause 

 which produced it continuing to act, bone contmues to be deposited, and 

 it generally appears in the form of a tumour, where the head of the 

 splint-bone is united with the shank, and in the front of that union. 

 This is called Bone Spavin, Inflammation of the ligaments of any of the 

 small bones of the hock, proceeding to bony tumour, would equally class 

 under the name of spavin ; but, connnonly, the disease commences on the 

 precise spot that has been described. 



Sjjavins, especially when the result of hereditary predisposition, vdW 

 sometimes be found of considerable size without either pain or lameness 

 being present during their formation. But when the result of inflamma- 

 tory action caused by concussion or other injury, lameness will nearly 

 always be present. ^Vllen the membrane of the bone has accommodated 

 itself to the tumour that extended it, the lameness subsides or disappears, 

 or depends upon the degree in wliich the bony deposit interferes with the 

 motion of the joint. It is well known to horsemen, that many a hunter, 

 with spavin that would cause his rejection by a veterinary surgeon, stands 

 his work without lameness. The explanation is this ; there is no reason 

 why an old bony tumour on the outside of any of the bones of the hock, 

 free from connection with the next bone, and from any tendon, should be 

 at all injurious ; as, for instance, one immediately under e or/, p. 385, but 

 from the comijlicated nature of the hock, it is difficult, if not impossible, 

 to be quite sui-e of the place or extent, from inspection of the tumour ; 

 and, besides, the disposition to throw out bone beneath the tumour may 



