STRUCTURE Ot" THE HOCK JOINT 21^ 



from the stifle to the hock ; it is connected with the 

 round bone above, and the os calcis below. 



c. The OS calcis^ which forms the posterior projecting part, 



called the point of the hock. 



d. The OS cuneiformc magniun^ large wedge-shaped or cunei- 



form bone, situated immediately under the astragalus. 



e. The os cuboides^ or cuboid bone, situate on the outer part 



of the hock. 



f. The OS cuneiforme^ or middle cuneiform bone, situated 



immediately underneath the large cuneiform bone, 

 and upon the hind cannon bone. 



g. The splint bone. 



/;. Upper head of the shank bone, or metatarsi magntim. 



This joint is subjected to very great stress and 

 weight, and consequently peculiarly liable to injury 

 both in the draught and during rapid motion. How- 

 ever, nature has constructed it with wonderful skill ; 

 and it is, by the beautiful adjustment of its parts, 

 rendered less liable to disease than might be ex- 

 pected from the important and heavy duties it has to 

 perform. The provisions made for this end are, 

 that the pulley-like heads of the astragalus and tibia 

 fit deeply into each other, and are strongly confined 

 in their position by extremely powerful ligaments, 

 which are so contrived that they admit of the 

 necessary freedom of the hinge-like motion of the 

 joint, but completely prevent that lateral or side 

 motion to which the joint is exposed in rapid move- 

 ments, or passing over uneven surfaces. It will be 

 seen, by inspecting the figure referred to, that the 

 weight of the hind-quarters is principally thrown upon 

 the tibia, b, and that it rests almost entirely on the 

 astragalus, a ; but it will be observed that this weight 

 does not press perpendicularly, but in an oblique 

 direction, so that much of the concussion which 



