64 form and action. 



The Knee. 



The knee of the quadruped is the part which corresponds, anato- 

 mically regarded, with the carpus or wrist of man : differently cir- 

 cumstanced, and differently used as the two parts are, yet is there 

 considerable analogy between them in structure. Each of them 

 is composed of eight bones, though in the knee only six out of 

 the number are placed so as to sustain pressure ; the remaining 

 two being situated behind the others, out of the line of the superin- 

 cumbent weight. One of these supplementary bones — called, from 

 its shape, trapezium — is affixed edgeways to the outer part of the 

 back of the knee-joint, and there answers the most important pur- 

 pose of furnishing a lever for those muscles whose office it is to flex 

 the leg : both celerity and force were required in this flexion or 

 catching-up of the leg off the ground in action ; and these are at- 

 tained through the advantages the muscles derive in their action 

 from the projection of the trapezium. When we see, therefore, 

 great breadth of the outer side of the knee, and that its hinder part 

 is very prominent, throwing the muscles attached to the point back 

 and so increasing the breadth of the arm, we may pronounce such a 

 horse to possess great power in flexing his legs, and commensurate 

 strength and quickness in action. 



There are six small bones, then, sorts of irregular or mis-shapen 

 cubes, placed between the two main straight shafts of support of the 

 fore limb, viz. the radius above, the cannon-bone below. Upon the 

 summit of the latter the three lowe'r of these bones, ranged in one 

 row; rest ; while upon the three constituting the upper row presses 

 the lower end of the radius. Why was the knee-joint constituted 

 in this manner 1 Why were these bones interposed ? Why was 

 not the end of the radius connected by joint at once with the end 

 of the cannon-bone 1 Because Nature had more objects to fulfil 

 than could have been accomplished by any simple or single form- 

 ation of joint. By a joint between the radius and cannon-bone 

 the weight would have been quite as well sustained as it is at 

 present ; but the concussion must have been greater : nay, the 

 motion might have been as great even as it is now between these 

 two bones ; but then, at the time that the leg was flexed on the 

 arm to the utmost, how would the knee-joint in front have become 



