POSTERIOR MEMBER. 263 



between the development of each of these secondary parts. The thick 

 hock merits this name and is truly beautiful only on condition of its 

 great transverse diameter at the level of the tibia, the astragalus, and 

 the superior extremity of the canon. 



The tarsal thickness indicates that of the leg, of the canon, of the 

 fetlock, and of the pastern. It bespeaks perfect steadiness and equi- 

 librium in every part of the hind limb ; while its breadth has the 

 entire command of the extent of the movements, the latter taking 

 place backward and forward and vice versa. 



It is evident, however, that this thickness in the draught-horse, for 

 example, should not be compared to that of the thoroughbred, two 

 types essentially different. In the one, the bones are voluminous, short, 

 and the muscles powerful ; in the other, the bones are long, relatively 

 slender, and the muscles long. If each requires, with equal propriety, 

 wide and thick articulations, absolute beauties applying to all services, 

 still it is necessary that the proportions and the general harmony should 

 not suffer thereby. 



Extent of the Tibio-tarsal Angle. As the hock is practically 

 only one articulation, the summit of an angle, it is not useless to 

 inquire if its degree of openness is capable of influencing the functions 

 of the parts, and if this angle, once determined, can owe the separation 

 of its branches to a greater or lesser inclination of the one or the other 

 of them. In other terms, what is the value of the tibio-tarsal angle, 

 and what is its orientation on the member to be in the most favorable 

 attitude for the development of force or the display of velocity ? 



Most writers have endeavored to answer this question by advancing 

 theoretical views insufficiently based on facts. Hence their writings 

 contain numerous contradictions. We think we have been more logical in 

 studying first very beautiful models, with a view of reasoning afterwards 

 more easily in the particular cases which present neither an absolute 

 beauty nor a veritable defect, and which are so often met in practice. 



Dismissing for a moment the obliquity of the leg, let us remark 

 that the angle of the hock undergoes more or less the influence of the 

 three metatarsal directions, as follows : 



a. The canon remains vertical. 



b. It is oblique forward and downward. 



c. It is oblique backward and downward. 



We will suppose, in each of these instances, the point of the hock 

 tangent to a vertical line which would start from the point of the but- 

 tock, as we remark it in the member with a normal axis. (See Axes.} 



a. The Canon, Vertical. The canon in this case is tangent 



