The idea of using conformation to better choose a horse to buy, or choose a horse for a specific discipline is not new. Xenophen described what he looks for in selecting a young horse: “a hoof of thick horn, and a frog that is held off the ground.” But he never mentions the “ideal” horse, or the “perfect” horse. A perfect horse does not exist. We can take our analysis of a horse’s conformation and use that information to make better decisions, but we don’t simply turn a horse away because his pasterns are not at the perfect angle.
We can then break the horse’s body into three parts:
1. The spine, neck and head
2. The forelegs, and
3. The hindlegs.
1. The spinal column consists of the skull, seven cervical vertebrae which begins at the 1stcervical vertebrae, or the atlas which allows the skull to make up and down movements. The 2nd cervical vertebra allows the side to side movements.
Moving down the back, the horse has eighteen thoracic vertebrae. Each thoracic vertebra is attached to a pair of ribs, that protect the heart and lungs. The withers are actually the spinous processes of the thoracic vertebrae, the peak of which is at thoracic 4, or T4. The more gradual decline of the withers from T4-T10 or T12, the better. The anatomical structure of the withers are important because the muscles that raise and lower the head and neck are anchored to the withers like a bridge. The spinous processes of the withers are actually slanted towards the tail.
After the thoracic vertebrae are the lumbar vertebrae. Equivalent to those in a human, horses have six lumbars, with flat transverse processes that protect the kidneys.
Within the top of the pelvis lies the sacrum; five fused vertebrae. The lumbosacral joint, or LS joint, is an important point of anatomy that we’ll return to later. The tail consists of around eighteen coccygeal vertebrae.
2. On the front leg of the horse it is important to notice there is no collarbone, or any bone-to-bone connection of the scapula and ribs. This provides better shock absorption and becomes a very important part of positioning the saddle.
Working our way down the front leg, we first have the scapula, humerus, radioulna and knee. The knee on the horse is the equivalent of our wrist, and the cannon bone, with the splints consist of three “fingers” that have telescoped over centuries of evolution, so the horse now sits on one middle ‘finger’. At the beginning of life the splint bones are attached by only cartilage. Around six years of age, they fuse to the cannon bone. Stress causes the fusion, so the timing varies greatly and generally the inside splint will fuse first. Almost always the front splints fuse before the hind because the front legs carry 60% of the horse’s weight.
Below the cannon is the fetlock joint which contains two sesamoid bones. Below the fetlock is the long pastern, followed by the short pastern (partially inside the hoof), coffin bones and navicular bone.
3. On the hind leg of the horse, blow the pelvis we have the femur, patella (our knee), the tibia, calcaneus (which is the point of the hock) and below that is almost identical to the front leg.
From this basic understanding of anatomy, we can begin to analyze the angles of the bones, how they affect the performance of the horse, and what we can do to work with what the horse has. Please feel free to comment or send me an email if you have any questions.