At the most fundamental (and perhaps most important) level, we strip away everything but the skeleton. It is often difficult to visualize the bones on a living horse, but with practice and careful scrutiny of anatomical drawings, the task becomes manageable and even fun. The skeleton is the framework upon which everything else rests. First, look at the legs—these are the most important parts of a horse’s physique. They support the considerable weight of the body. They balance a horse through its movement and tight turns and absorb the concussive shock of running. The front legs support 60% of a horse’s mass. They should be straight when viewed from the front; angular (“offset”) legs result in undue stress being placed on the joints, possibly leading to future soundness problems. The circumference of the leg bones should be large enough to support the size of the horse and the tack and rider it will eventually carry. Look at the slope of the pastern—the shock absorber of the lower limb—too straight, and the gait will be stiff, choppy, and rough; too sloped, and the ride will be smoother, but the tendons may suffer from hyperflexion, which could lead to chronic lameness and soft tissue injury.
Above: The horse at the left exhibits calf knees or backwards knees, a severe conformation fault with potential lameness implications if used for strenous athletic work. The middle horse shows perfectly straight legs with solid strong bone structure. The horse at the right is slightly bent over at the knee, perhaps caused by hard use earlier in life. This is more consmetic in nature than truly detrimental. All horses pictured above have good angle to their pasterns and adequate length, though some disciplines might like them to be marginally longer for smoothness in gait. The middle horse has good ratio of bone length from upper to lower leg (short cannons are ideal for greater speed and fluidity of movement). The horse at the right has slightly longer-than-ideal cannon bones. The hind legs, while generally less plagued by chronic soundness issues, are nonetheless important to consider. Watch out especially for hocks that are too straight (“posty”). Without an adequate angle to the joint, too much stress is placed on the horse’s whole hind end, which may eventually cause long-term problems such as arthritis. While not ideal, hocks with excessive angle (“sickled”) are far less likely to cause lameness or negatively impact performance.
Above: The halter horse on the left displays post hocks (too straight through the joint), which is sadly characteristic of animals in this discipline. This conformation flaw impedes proper movement of the joint and can lead to injury through concussive force, including eventual arthritis. The middle horse possesses a severe case of sickle hocks. Notice how the point of the hock extends far behind the point of the hip at rest. While this is more common among gaited horses and may in some ways actually benefit their desired movement, conformation extremes of any type are undesirable and may affect soundness. The horse on the right has adequate hock structure. Moving down the legs, now look at the feet. As the saying goes, “no hoof, no horse.” Generally speaking, the larger the hoof, the better. This provides good circulation and blood flow throughout the horse’s whole body, as each step helps pump blood back up the vertical veins. A large hoof also helps to distribute a horse’s mass over a bigger surface area, preventing any one point from having too much built-up pressure. The slope of the hoof should match that of the pastern. The foot should also be healthy, with a large, well-defined frog, thick wall, and adequate heel. A farrier can work wonders on a problem hoof, but only if the proper conformational structures are there to begin with. Now examine the horse’s topline. Look for a good set of withers to hold the saddle in place. Tall, thin withers might be difficult to fit and may require special pads to place the saddle properly. Flat “mutton” withers, on the other hand, will cause a saddle to roll, no matter how tight the girth is fastened. The length of back is also worth considering. A short back is generally considered a good thing, but excessive shortness can lead to over-reaching and interference between the hind and front legs. It can also result in a rougher gait. However, a short back is very strong—think of a suspension bridge. Conversely, a longer back is weaker and over time may become sore or begin to atrophy and become swayed. As with most things, a happy medium between the two extremes is best.
Above: The top gray horse has a slightly downhill build and is mutton-withered, making saddle fit and the prevention of slipping difficult. The muscles over the back, however, appear strong. The middle black horse has a good set of withers and a nice short, level back ideal for supporting weight. The bottom Paint horse is developing swayback and muscle atrophy due to the back's slightly excessive length, downhill build, and high withers. Next, draw an imaginary line from the peak of the withers to the point of the shoulder. This is the shoulder’s slope. Again, look for a good angle. For good balance, the angle here should match that of the front pasterns and hooves. As before, a shoulder that is too straight will cause roughness of movement. A more sloping shoulder leads to greater length of stride and freedom of movement. On the front end, the shape of the head is often a matter of personal preference, although some believe that skull structure predicts personality and temperament. The throatlatch should be slender to facilitate bending and flexion. The neck should have adequate length to allow for collection. “Ewe necks”—those where the muscling underneath exceeds that on the crest—cause a horse to carry its head sky-high and hollow its back, both undesirable. The “correct” length and set of a neck will vary greatly depending on breed and discipline.
Above: The first horse displays a typical upside-down or "ewe" neck--the length of the bottom exceeds that of the crest, and the muscling underneath is also heavier. This causes a horse to carry its neck and head erect, hollow its back, and limit collection. To an extent, this mode of carriage and the muscling of the neck can be improved through proper training and conditioning. The middle horse displays a lovely neck and carriage for a stock breed. The neck may tie in slightly low, but the length and thickness are excellent, and the throatlatch is fine and clean, meaning that the neck is flexible and aids in collection. The third horse has an overly-thick "bull neck" and thick, inflexible throatlatch, as well as some over-muscled "ewe-ing" on the underside. In addition, the heavy fatty crest suggests obesity or possibly metabolic problems. All horses in the above photos possess adequate shoulders, though the horse on the right is closest to ideal (being laid back and nicely sloped), while the first two animals have slightly straighter shoulders. Finally, travel back to view the slope of the croup. This, too, is contingent upon breed and discipline. Arabian breeders, for example, prefer a very flat croup, while Western speed event riders like more slope to help a horse “get under himself” better in the fast stops and turns.
***While it is helpful to break a horse down piece by piece, as outlined above, the entire animal should be taken into consideration as an integrated unit. The subjective sense of “balance” is important. Watch the horse move and see how its gait reflects its conformational structure and how it will help or hinder its intended use. Oftentimes small conformational blemishes can be more than made up for by other aspects. That elusive quality called heart also factors heavily in performance and athletic ability. However, analyzing the conformation of a horse helps to predict what future soundness problems might occur, so that preventative measures might be taken accordingly. It can also be used to predict successful participation in a discipline and evaluate the suitability of breeding stock. In the end, it is the comfort and happiness of horse and rider that matter most.