12 THE CANADIAN HOESE 



without causing much annoyance. The other form, arising 

 from inflaipmation of the internal structures of the hock- 

 joint, is frequently attended by caries or ulceration, and from 

 the first produces intense pain and lameness, when the bones 

 rub on one another. » 



Y The hock-joiat corresponds to the heel in man , and has 

 no fewer than ten bones entering into its formation, an ac- 

 quaintance with the arrangement of which is necessary be- 

 fore the complexities of hock diseases can be understood. 



As in the fore-leg, we have the cannon-bone, with the 

 two small splint-bones, one on each side. Upon the heads 

 of these rest or articulate the bones proper of the hock, in 

 the following order. A The middle cuneiform or wedge-bone 

 lies immediately on the head of the cannon ; closely fitting 

 the upper surface of this bone, we have the large wedge- 

 bone, and articulating with the upper surface of which we 

 have the knuckle-bone or astragalus, which presents on its 

 upper surface a pulley-like articulation, fitting a correspond- 

 ing surface on the lower end of the tibia, or thigh-bone, of 

 the horse. jThis joint is the true hock-joint, f Ou the out- 

 side of the joint we have the cube-bone or cuboid. It ar^ 

 ticulates with the greater and middle cuneiform-bones by its 

 inner surface, by its upper surface with the astragalus and 

 OS calcis or heel-bone, and by its under surface with the 

 cannon and outer spUnt-bone. We have next the small 

 cuneiform, placed at the back part of the inner side of the 

 hock, resting partly on the large and partly on the middle 

 wedge-bone, but principally by its under surface with the 

 head of the inner spUnt-bone, and slightly with the cannon. 

 Lastly, we have the os calcis or heel-bone. It forms the pro- 

 jection called the cap or point of the hock ; it articulates 

 principally with the astragalus, and slightly with the cube- 

 ,bone. It will be well to bear in mind the four principal ar- 



