Conformation Essentials: Side View
Illustrations courtesy of the American Youth Horse Council's Horse Industry Handbook
Feet - A horse's hooves must be able to withstand a great deal of pressure. At full speed, a 1,000-pound Thoroughbred will place the equivalent of 100 times the force of gravity on each hoof with every stride, so it is essential that the foot be shaped properly to withstand this concussion and to dissipate the shock of impact. Consider the proportion, substance and size of the hoof. The underside of the hoof should have a round, slightly oval shape, with some depth. Some believe that larger feet indicate an aptitude for turf racing.
Pasterns - The pastern should be at a 45-degree angle (example A; example B shows a too-sloping pastern; example C shows a too-upright pastern). Its length should be proportionate; too long a pastern could indicate weakness and tendon strain, while if too short it may absorb too much concussion, thus stressing the bone structure.
Ankle - As with the pastern, the ankle-joint size should be proportionate to the rest of the leg. Beware of spread or prominent sesamoids.
Cannon bones - Ideally, the cannon bone should be short, strong, and have mass. The cannon bone bears the most weight of any bone in a horse's body. The bone should exit the lower knee or hock cleanly and be well-centered.
Knee - Bones in and leading to the knee should line up in a balanced manner; not tilting forward ("over at the knee" or "buck-kneed") or back ("back at the knee" or "calf-kneed"), nor severely offset to one side or the other.
Shoulder - The shoulder should have the same slope or angle as the pastern (see diagram at right). The ideal slope of the shoulder is approximately 45 to 50 degrees. In general, the angle of the pastern will correspond with the angle of the shoulder. Stride length is largely determined by the conformation of the shoulder. The straighter the shoulder, the shorter the stride. Also, a straight shoulder absorbs concussion instead of dispensing it and will put stress on the bones of the leg and shoulder.
Neck - A horse's neck should be sufficient in scope to provide adequate wind for the horse and be well tied in at the withers, while not being too low or "ewe necked." A horse with a well-muscled, well-proportioned neck has a longer, more rhythmic stride and can more easily maintain its balance when running. An easy, rhythmic stride will cause less fatigue while racing. Fatigue can increase the chances of injury. In short, does the neck fit the rest of the body?
Head - The head should be broad enough to permit adequate air passage. Generally, the distance from the back of the jaw to where the head ties into the neck should be about the size of a fist. Nostrils should be of adequate size. People refer to an "attractive" head. That usually means the head is short, with well-set ears; has large bold eyes, a short distance from eye to muzzle, large nostrils and a refined muzzle with a shallow mouth. In general, there is no physiological benefit to the horse having an "attractive" head. An "ugly" head functions similarly to an attractive head.
Eye - The eyes should be big and bright. Look for an intelligent, keen eye. A horse with a lot of white around the eye is often nervous and flighty.
Back - The distance from the withers to top of croup or hips should match the length of the horse's neck from the poll to the withers. The length of the back is directly related to the slope of shoulder. The steeper the shoulder, the longer the back. A horse with a long back is usually not as well balanced as a short-backed horse.
Hips/Buttocks - The croup or hip should have a gentle slope; not too steep or flat - and good width. The gaskin should depict strength and should complement the muscles of the quarters.
Hocks - A horse's hocks should not be straight as a post, nor curved so deeply as to be "sickle-hocked," but somewhere in between. Ideally, if you dropped an imaginary plumb line from the point of the buttocks to the ground, it should run parallel to the cannon bone and be slightly behind the heel.
Stance - Does the horse stand with hocks tucked up underneath the body, "sickle-hocked," or behind the body like a German Shepherd? The horse should be standing balanced and straight. The same goes for the front legs. Is the horse straight and balanced or is it camped under (example A, right) or camped out (example B)?