In geometry, the name poise is given to a line perpendicular to the horizon and, based on this principle, the name "poise on the horse" is given to the perpendicular lines that determine the correct direction that its members should have.

Thus, the address of the above must be such that it meets the following conditions:

These lines determine the direction that the extremities must have so that the weight of the trunk gravitates on them with the equality that corresponds in the season and in the march. When the limbs do not follow these directions, more or less serious damage occurs, whatever the work to which the horses are subjected.

When the vertical line, drawn from the sine of the angle formed by the back with the arm on the ground, does not pass through the center of the underside of the hoof but lies behind this line, the horse is said to be under itself. This defect generally depends on the short length and lack of perpendicular direction of the pasterns and the weight of the front quarter that gravitates on the front limbs, acting more on the lumens than on the rest of the hoof.

The opposite happens when the center of the lower face of the hull is in front of the vertical line. This defect, which generally depends on the great length and obliquity of the pastern, places the weight of the forequarter more on the heels than on the rest of the hoof. In both defects the strength of the horse's movements is reduced.

If in the hind limbs, the vertical line, drawn from the center of the thigh joint with the haunch on the ground, does not touch the center of the lower face of the hoof but rather this part is in front of said line, the weight of the hindquarter weighs more on the heels than on the rest of the hoof. The hocks are very elbowed and the feet are very close to the center of gravity, which decreases the extent of the hock movements, making the percussions of the hindquarters shorter and consequently the horse's gait shorter.

In the opposite defect, that is, when the center of the lower face of the hoof is behind the vertical line, the same damage results as when the hind limbs are short, in which case the weight of the hindquarter weighs more on the lumens or anterior and lower part of the hoof.

Finally, if the limbs are separated from the perpendicular line that descends from the posterior third of the upper and outer part of the forearm to the ground, either forward or backward, or if they depart inside or outside the vertical lines drawn from the anterior, middle and lower part of the forearm to the ground and from that which descends from the upper, middle and posterior part of the calcareous to the ground, and which must divide the remaining pieces of the limbs into two equal parts, experience has shown that horses do not comfortably resist work at those who submit, their marches being short, without agility and without strength; The weight of the trunk and the loads they support or the efforts they make always try to increase these vicious directions, advantageously resisting the strength of the muscles and ligaments that must oppose these defects of direction, forcing them to remain in a violent and permanent action, which soon produces their weakness and the horses rub against each other, reach each other, etc.