ASKHQ: PASTERN BONE

Q: When is a pastern considered too short?

Q: The pastern is the area between the fetlock joint and the top of the hoof, and consists of two bones: the long pastern bone, or first phalanx, under the fetlock joint, and the short pastern bone, or second phalanx, which joins with the coffin bone, the third phalanx, inside the hoof. The length and slope of the pastern influences the soundness of the leg joints above it. This conformation thus determines how well the leg is able to tolerate concussive forces, and also contributes to the action of the horse, determining whether he has bounce or is flatter in his movement.

A too-long pastern reduces a horse’s potential for speed, as it takes longer to ‘push off’ at each step to get the foot off the ground. Many horse-people thus feel that short pasterns are actually an advantage for propulsion, but this is dependent on whether the pastern slopes enough to absorb concussive forces. A horse can usually cope well with short pasterns if they slope, or long pasterns if they are at a steep angle. However, the opposite combination (short and upright or long and sloping) can create issues for the horse. Short, upright pasterns mean that all of the force from the upper leg joints is transmitted straight down into the foot, which causes soundness issues and usually shortens the working life of the horse.

The length of the pastern is therefore important, but it is not the sole factor for examination when trying to assess pastern conformation. However, generally speaking, a pastern is considered to be too short if it is less than half of the length of the cannon bone.