Beauty may be in the eye of the beholder, but good conformation is a matter of physics. A horse that is well-built for his job will stay sound and perform better than one that has poor conformation. – J. Landels
Ideal Conformation: Head-to-Tail-to-Toe
Head: Proportional to the size of the body, long with well defined features and ample room for the nasal passages teeth, tongue and top of the windpipe. The angle where the head meets the neck must not be too acute, otherwise it may restrict the horse’s breathing by compressing the larynx.
Jaws: Strong and broad with sufficient width between the jaws to accommodate the large amount of airflow required for optimal respiration. To ensure proper grinding of food and even wear of the teeth, the jaws should meet evenly and have good up-and-down and side-to-side motions.
Eyes: Horse’s with deep-set eyes may have a slightly limited field of vision. Prominent, round eyes that are widely-spaced at the sides of the head enable horses to see nearly 360 degrees. The eyes should also be bright, clear, alert, and intelligent in appearance. Eyes that are dark brown in colour may be preferable, as blue and green eyes are more photosensitive.
Ears: Ears should be proportional in size to the head. If they are too long, the horse is said to have mule ears, too far apart or droopy, they are considered lopped. Either way, this is generally of minimal concern.
Muzzle: The muzzle should be small with large, open, thin-walled nostrils to intake large volumes of oxygen. Firm, muscular lips are needed to select and grasp food.
Neck: The neck, although slender, should be muscular and slightly arched along the topline, from withers to poll, with a straight underline.
Withers: Well-defined, medium high, sloping withers usually indicate longer shoulder muscles, which allow for increased extension of the forelegs and freer movement of the hindlegs. They also help keep a saddle in place.
Chest: Well-defined and fairly wide, without being extremely wide or overly narrow. An overly narrow chest will result in the forelegs being too close together, and too much width will cause a rolling motion when the horse is in motion. A slight pectoral bulge should be visible from the side.
Forelegs: Long, sloping shoulders, angled toward the front to meet the upper arm, which angles toward the back to meet the forearm, then straight down from the elbow to the fetlock, where the foreleg angles toward the front again through the pastern to meet the hoof. The angles of the shoulder, pastern and hoof wall should be equal to maximize shock-absorption.
Back: The back should be relatively short, straight and wide to support the weight of the horse’s ribs, muscles and organs, as well as the weight of a rider while allowing the horse to maintain balance.
Loin: The loin plays a key role in impulsion and is most effective at supporting the lumbar vertebrae and transferring power forward from the hindlegs when it is short and well developed.
Barrel: The barrel should be deep and wide to accommodate the horse’s large heart and expanding lungs with a spacious rib cage to protect them, along with the internal organs. Backward sloping, largely-spaced ribs allow for full expansion of the lungs.
Hind legs: Providing most of the power for locomotion, the hind legs also absorb a great deal of concussive force. Well muscled and strong, the angles of the stifle and hock are less than those of the shoulder and upper arm. The point of buttock, point of hock, and back of the cannon should line up with one another in a straight line.
Hindquarters: Appearing square and symmetrical when viewed from behind, with a rounded croup, the muscular, powerful hindquarters play a key role in moving the horse.
Feet: Well-proportioned and set squarely on the legs with rounded toes and broad heels, the feet should be balanced and symmetrical, allowing for even distribution of concussive forces.
Hooves: See Hoof Anatomy.
Equine Research. (2004). Horse Conformation: Structure, Soundness, and Performance. Guilford CT: The Lyons Press. Hood, D.M. and C.K. Larson. 2013. Building the Equine Hoof. Eden Prairie, Minnesota: Zinpro Corporation.