58 MECHANISM OF EQUINE LOCOMOTION 



Mechanism of the Hock Joint. Figs. 39, 40, and 41 show the 

 three actions of this joint as a lever. 



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

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



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 m which the hind foot is carried; its object being, as explained 

 by H. Bouley, to allow the *stifle to clear the belly, when the hind foot 

 IS brought foiward. 



