386 ENLARGEMENT OF THE IIOCK. 



Considering the situation and action of this joint, the weight and stress 

 thrown upon it must be exceedingly gi^eat, and it is necessarily liable to 

 much injury in rapid and powerful motion. What are the provisions to 

 prevent injury ? The grooved or pulley-like heads of the tibia and the 

 astragalus, received deeply into one another, and confined by powerful 

 ligaments, admitting freely of hinge-like action, but of no side motion, to 

 which the joint would otherwise be exposed in rapid movement, or on an 

 uneven surface. A slight inspection of the cut will show that the stress 

 or weight throwTi by the tibia, a, on the astragalus, h, docs not descend, 

 perpendicularl}', but in a slanting direction. By this, much concussion is 

 avoided, or more readily diffused among the different bones ; and, the joint 

 consisting of six bones, each of them covered with elastic cartilage, and 

 each admitting of a certain degree of motion, the diminished concussion is 

 diffused among them all, and thereby neutralised and rendered compara- 

 tively harmless. Each of these bones is covered not only by cartilage, but 

 by a membrane secreting synovia; so that, in fact, these bones are formed 

 into so many distinct joints, separated from each other, and thereby guarded 

 from injury, yet united by various ligaments — possessing altogether 

 sufficient motion, yet bound together so strongly as to defy dislocation. 

 When, however, the work which this joint has to perform, and the 

 thoughtlessness and cruelty with which that work is often exacted, are 

 considered, it will not excite any surprise if this necessarily complicated 

 mechanism is sometimes deranged. The hock, from its complicated sti-uc- 

 ture and its work, is the principal seat of lameness behind. 



ENLARGEMENT OE THE HOCK. 



First, there is inflammation arising from injury, such as kicks or blows, 

 or sprain of the hocJc-joiiit generalli/, arising from sudden "v-iolent concussion, 

 by some check at speed, or overweight, and attended with enlargement 

 of the Avhole joint, and great tenderness and lameness. This, however, 

 like other diffused inflammations, is not so untractable as an intense one of 

 a more circumscribed nature, and by rest and fomentation, local bleeding 

 and physic, followed by counter-irritation, the limb recovers its action, 

 and the horse becomes fit for ordinary Avork. When it is the result of 

 external violence, especially, as is frequently the case, from being kicked 

 by another animal, inflammation often runs very high, the hock being much 

 swollen and great pain and lameness present. This may go on increasing 

 in violence for several days, and sometimes extends to the interior of the 

 joint, and terminates in the joint becoming open, or the pain and lameness 

 gradually decrease. The SAvelling, however, does not always subside, and 

 enlargement spread over the whole of the hock -joint sometimes remains. 

 The treatment should consist in keeping the animal perfectly at rest, and 

 the continued application of fomentations of warm water for two or three 

 hours at a time. A dose of physic should be given, and blood may be 

 abstracted from the femoral vein. If the inflammation extend to the interior 

 of the joint and it becomes open, no treatment Avill do much good, as the 

 excessive irritation Avill often destroy the animal. If, however, Avhen the 

 A-iolence of the symptoms have abated, considerable enlargement of the 

 hock remains, it should be repeatedly blistered. A horse with an enlarged 

 hock must always be regarded ■\\"ith suspicion. In truth, he is imsound. 

 The parts, altered in striicture, must be to a certain degree Aveakened. The 

 animal may discharge his usual Avork during a long period, Avithoat return 

 of lameness ; but if one of those emergencies should obcur Avhen all his 

 energies require to be exerted, the disorganised and weakened part Avill 

 fail. The purchase, therefore, of a hoi'se Avith enlarged hock Avill depend 



