584 DISEASES OF THE HORSE. 
The bones are still further bound together 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 coffin bone 
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 pas- 
terns and coffin bone backward. One of the tendons is attached to 
the upper end of the short pastern, 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 coffin bone. 
These two tendons nct 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. 
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 pasterns and coffin 
bone, should always be straight—that is, never broken, either forward 
or backward when viewed from the side, or inward or outward when 
observed from 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 tce. 
Raising the heel or shortening the toe not only tilts the coffin bone 
forward and makes the hocf stand steeper at the toe, but slackens the 
tendon that attaches to the under surface of the coffin bone (perforans 
tendon), 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 for- 
ward; 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, raising 
the tce or lowering the heels of a foot with a straight foot-axis not 
cnly tilts the coffin bone backward and renders the tce more nearly 
horizontal, but tenses the perforans tendon, which then forces the fet- 
lock 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. 
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 coffin bone 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 
