336 THE KNEE. 



The perforated tendon soon afterwards divides, and is inserted into the smaller 

 and larger pastern bones, and serves to flex or bend the fetlock and joints, as 

 it had previously assisted in the flexion of the knee. 



The flexor perforam muscle has nearly the same origin as the perforatus; 

 but it continues muscular farther down the arm than it, and lies before it. At 

 the knee its tendon passes, like the perforatus, under strong ligamentary arches, 

 which confine it in its situation. It then becomes round, and is partly enveloped 

 in the perforatus, and at the fetlock is entirely surrounded by it. It emerges 

 from the perforatus when that tendon divides, and continues its progress alone 

 after the other has inserted itself into the pasterns, and, passing over the navi- 

 cular bone, is broadly implanted into the posterior cavity of the foot. 



It is sufficiently plain that the arm should be large and muscular, otherwise 

 it could not discharge all these duties. Horsemen differ on a variety of other 

 points, but here they are agreed. A full and swelling fore-arm is the charac- 

 teristic of every thorough-bred horse. Whatever other good points the animal 

 may possess, if the arm is narrow in front and near the shoulder, flat on the 

 side, and altogether deficient in muscular appearance, that horse is radically 

 defective. He can neither raise his knee for rapid action, nor throw his legs 

 sufficiently forward. 



The arm should likewise be long. In proportion to the length of the muscle 

 is the degree of contraction of which it is capable ; and in proportion also to the 

 degree of contraction will be the extent of motion in the limb beneath. A racer, 

 with a short arm, would be sadly deficient in stride ; a hunter, with the same 

 defect, would not be able to double his legs well under him in the leap. There 

 is, however, a medium in this, and the advantage of length in the arm will 

 depend on the use to which the horse is applied. The lady's horse, the cavalry 

 horse, every horse in which prancing action is esteemed a beauty, and in which 

 utility is, to a certain degree, sacrificed to appearance, must not be too long in 

 the arm. If he is long there, he will be proportionably short in the leg ; and 

 although this is an undoubted excellence, whether speed or continuance is 

 regarded, the short leg will not give the grand and imposing action which 

 fashion may require. In addition to this, a horse with short legs may not have quite 

 so easy action as another whose length is in the shank rather than in the arm. 



THE KNEE. 



The Knee (M, p. 108, and cut, p. 327), answering to the human wrist, consti- 

 tutes the joint or joints between the arm and the shank or leg ; and is far more 

 complicated than any joint that has been yet considered. Beside the lower 

 heads of the bone of the arm, and the upper heads of the three bones of the 

 leg, there are no less than six other bones interposed, arranged in two rows 

 three in each row, and the seventh placed behind. 



What was the intention of this complicated structure ? A joint between the 

 elbow and the fetlock was absolutely necessary to the action of the horse. An 

 inflexible pillar of that length could scarcely have been lifted from the ground, 

 much less far enough for rapid or safe motion. It was likewise necessary, that 

 the interposing joint should be so constituted as to preserve this part of the 

 limb in a straight direction, and possess sufficient strength to resist all common 

 work and accidents. Being in a straight direction, the shock or jar between the 

 ends of the bones of the arm and the leg would be dreadful, and would speedily 

 inflict irreparable injury. The heads of all bones are covered with elastic car- 

 tilage, in order to protect them from injury by concussion ; but this would be 

 altogether insufficient here. Six distinct bones are therefore placed here, each 

 covered above and below by a thick coating of cartilage, connected together 

 by strong ligaments, but separated by interposed fluids and membranes. The 



