The alignment and health of the horse's legs and feet are vital to the horse's usability. "No foot, No horse" is an old horseman's adage; as true today as it was 2500 years ago!
The horse's foot is unique in that it supports the weight of the horse on one digit. It has particular needs in domestic situations in order to provide shock absorption, support and circulatory function. These needs include a properly trimmed and balanced hoof as well as living conditions that mimic a wild horse's living conditions.
Nailing a metal shoe to this most vascular and important part of the horse's anatomy is similar to the foot binding that was done to female children in ancient China. The horse shoe deforms the equine foot and eventually may lead to diseases resulting in lameness and eventual euthanasia.
The Bones of the Front Leg and Foot
The bones of the horse's feet are somewhat similar to the bones in a human's finger. There are some differences too.
The horse's front legs, beginning with the shoulders, support 65% of the horse's weight while at rest. The shoulder blade is attached through muscles and tendons to the thorax. There is no actual bone-to-bone attachment. This means that the horse can raise his thorax by contracting the muscles of his shoulder much like the human can shrug their shoulder or raise the chest.
The shoulder has a joint to the humerus similar to our shoulder, allowing the horse to reach forward and back as well as from side to side. The elbow is the joint near where the rider's toe reaches when mounted. It allows the leg to be raised and lowered.
The horse's "arm" is similar to our forearm. The horses' "knee" is synonomous with our wrists.
From there the horse's lower legs are a result of evolutionary economy and necessity. The cannon bone is synonomous to one of the bones inside our hands. The reduction of "fingers" leaves the horse with a "splint" bone on either side of the cannon bone. These are vestigal remanents of fingers. The vestigal remanent of the thumb is the chestnut, located on the inside of the leg just above the "knee". The ergot, located beneath the fetlock, is another finger remanent representing the pinkie.
Leaf Spring Shock Absorption Mechanism of the Bone Alignment in the Foot
The cannon bone is joined to the long pastern bone (P1) which is joined to the short pastern bone (P2). These bones, along with the bones inside the hoof capsule, have boney attachments for the major tendons of the flexor and extensor muscles in the arm and shoulder. The sesamoids at the back of the fetlock serve as fulcrums for the flexor tendon allowing it to slide over the angle of the fetlock.
A balance of the flexor and extensor systems of muscles and tendons ( tendons attach muscles to bone) depends on a balanced coffin bone located within the hoof capsule. When the coffin bone is balanced within a properly trimmed hoof, the angle of the pastern from the fetlock to the coffin bone provides a "leaf spring" shock absorption system. As the weight descends into the leg, the fetlock drops briefly into the tension of the flexor tendons.
If these bones did not have a balanced hoof capsule and the bones of the pastern were vertically aligned, the shock of each step would be taken by the cartilage in between the pastern and coffin bone. It wouldn't be long before the horse's joints would wear out. This kind of alignment is unfortunately common due to rampant heel pain and ignorance about correct conformation of the foot.
Inside The Hoof Capsule
The horse standing with his weight balanced on the last bone of his middle finger, can sleep standing. This is called the "stay apparatus" and depends on the horse standing on a correctly trimmed and comfortable hoof.
The hoof capsule is comprised of the wall and bar horn, sole horn, frog horn and periople. On the inside of the hoof capsule are the coffin bone and navicular bone. The coffin bone (P3) is attached to the hoof wall dorsally, medially and laterally via the laminar horn. The health of the laminar horn is very important. (Laminitis and Holistic Treatment for Barefoot Horses) It tightly attaches the coffin bone and suspends the weight of the horse much like the springs of a trampoline.
The navicular bone (distal sesamoid) serves as a fulcrum allowing the flexor tendon to attach to the underside of the coffin bone. Along with the frog, digital cushion and lateral cartilages, the horse depends on an angled pastern and a balanced hoof capsule with a near ground parallel coffin bone inside it to carry his weight and absorb the shock of each step.
Sandra Judy - An avid horse woman for all of her life, Sandra has providedholistic hoofcare education through clinics and her website. She began with ...
