70 



MECHANISM OF EQUINE LOCOMOTION. 



always be kept " short," and that shoes should be no thicker at the toes than 

 what would be sufhcient to enable them to stand " wear." I need not allude 

 further to this subject, as I have considered it in my Veterinary Notes for 

 Horse Owners. 



Mechanism of the Hock Joint. Figs. 30, 31, and 32, show the three 

 actions of this joint as a lever. 



Besides flexion and extension, this joint has an outward motion, due to 

 the outward and forward direction of the pulley formed by the astragalus. 



Fig. 30. — 1ST Order. 



Fig. 31. — 2ND Order. 

 Levers of the Hock. 



Fig. 32. — 3RD Order. 



We find, contrary to what we might have expected from an inspection of this 

 bone, that this oblique play of the hock joint does not affect the direction in 

 which the hind foot is carried ; its object being, as explained by M. H. Bouley, 

 to allow the stifle to clear the belly, when the hind limb is brought forward. 



