BREEDS OF HORSES 103 



extension and flexion in a single plane, some slight rotation and 

 lateral movements are possible. 



Tendons and Flexors. The bones are still further bound to- 

 gether and supported by three long fibrous cords or tendons. One, 

 the extensor tendon of the toe, passes down the front of the pasterns 

 and attaches to the coffinbone just below the edge of the hair ; when 

 pulled upon by its muscle this tendon draws the toe forward and 

 enables the horse to place the hoof flat upon the ground. The other 

 two tendons are placed behind the pasterns and are called flexors, 

 because they flex, or bend, the pasterns 'and coffinbone backward. 

 One of these tendons is attached to the upper end of the short pas- 

 tern, while the other passes down between the heels, glides over the 

 under surface of the navicular bone and attaches itself to the under 

 surface of the coffinbone. These two tendons not only flex, or fold 

 up, the foot as the latter leaves the ground, during motion, but at 

 rest assist the suspensory ligament in supporting the fetlock joint. 



Foot-Axis. The foot-axis is an imaginary line passing from 

 the fetlock joint through the long axes of the two pasterns and coffin- 

 bone. This imaginary line, which shows the direction of the pas- 

 terns and coffinbone, should always 'be straight that is, never 

 broken, either forward or backward when viewed from the side, or in- 

 ward or outward when observed in front. Viewed from one side, 

 the long axis of the long pastern, when prolonged to the ground, 

 should be parallel to the line of the toe. Viewed from in front, the 

 long axis of the long pastern, when prolonged to the ground, should 

 cut the hoof exactly at the middle of the toe. 



Raising the heels or shortening the toe not only tilts the cof- 

 finbone forward and makes the hoof stand steeper at the toe, but 

 slackens the tendon that attaches to the under surface of the coffin- 

 bone, and therefore allows the fetlock joint to sink downward and 

 backward and the long pastern to assume a more nearly horizontal 

 position. The foot-axis, viewed from one side, is now broken forward ; 

 that is, the long pastern is less steep than the toe, and the heels 

 are either too long or the toe is too short. On the other hand, rais- 

 ing the toe or lowering the heels of a foot with a straight foot-axis 

 not only tilts the coffinbone backward and renders the toe more 

 nearly horizontal, but tenses the perforans tendon, which then 

 forces the fetlock joint forward, causing the long pastern to stand 

 steeper. The foot-axis, seen from one side, is now broken backward 

 an indication that the toe is relatively too long or that the heels are 

 relatively too low. 



Lateral Cartilages and Plantar Cushion. The elastic tissues of 

 the foot are preeminently the lateral cartilages and the plantar 

 cushion. The lateral cartilages are two irregularly four-sided plates 

 of gristle, one on either side of the foot, extending from the wings of 

 the coffinbone backward to the heels and upward to a distance of an 

 inch or more above the edge of the hair, where they may be felt by 

 the fingers. When sound, these plates are elastic and yield readily 

 to moderate finger pressure, but from various causes may undergo 



