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Medical Index
First Posted: Aug 7, 2010
Last Update:Aug 1, 2013

All About the Horse's Conformation/Part 2

All About the Horse's Conformation/Part 1
All About the Horse's Conformation/Part 3

The Chest

Narrow Breast

With the horse standing square, the width between the front legs is relatively narrow. However, this can be skewed by how far apart feet are placed at rest. A narrow breast often represents general thickness and development of shoulder. A narrow breast is usually seen in Gaited horses, Saddlebreds, Paso Finos, and Tennessee Walkers. A horse's ability to carry weight is dependent on the size of its chest, so a horse that does not do well with draft work may be fine in harness or with a light rider. Narrowness may be from turned-in elbows which can cause toes to turn out, making the horse appear narrow. Narrowness in the chest may be from immaturity, poor body condition, inadequate nutrition, or under-developed breast muscles from a long time in pasture and lack of consistent work. The horse usually has undeveloped shoulder and neck muscles. The horse may tend to plait, and is more likely to interfere, especially at the trot. The horse is best for pleasure riding, driving in harness, and trail riding.

Pigeon-breasted horse, with the sternum protruding

The front legs come too far back under the body, giving a bulky appearance to the breast as viewed from the side. The front legs lie behind a line drawn from the withers to the ground, setting the horse under himself. It is often associated with a long shoulder blade that drops the point of shoulder somewhat low with the arm bone relatively horizontal, setting the elbow more to the rear. A relatively uncommon fault, mostly seen in Quarter Horses with big, bulky muscles. Bulky breast muscles and legs set under the body decrease the efficiency of stride and swing of shoulders, thus hastening fatigue. It may interfere with the front legs, forcing them to move to the side rather than directly under horse. Causes a "rolling" gait that slows the horse's speed, especially at the gallop. Should have little interfering in the sprinting sports that need rapid acceleration. The inverted V of the pectorals are important for quick turns, doges, and spins needed by stock horses. This conformation quality is most useful in Quarter Horse racing, barrel racing, roping, and stock horse sports where a low front end crouches and the horse makes quick turns.

Conformation of the Body

Mutton Withers

The horse has flat and wide withers, from short spines projecting off the 8th-12th vertebrae. Seen in any breed. The withers are an important attachment for ligaments and muscles that extend head, neck, shoulder, and back vertebrae, and are also insertion point for muscles that open ribs for breathing. If mutton withered, the horse has less range of motion when extending the head and back muscles, so is less able to elevate its back with its head and neck extended, which affects ability for collection. Difficult to hold on saddle. If saddle slides forward, it can put weight on the forehand, interfering with balance and restrict the shoulder movement by saddle and rider movement, causing shortened stride, interfering or forging. The horse is often difficult to fit with a driving harness Pleasure riding and non-jumping activities are best for the horse.

Hollow Behind Withers

A "shelf" behind the withers, gives a hollow appearance, often created by lack of muscular development Usually found in high-withered horses of any breed. Often implies a less-developed muscular bed for the saddle to rest on. The saddle will often bridge in this area to pinch the withers, creating soreness of the withers and muscles. The horse is then less willing to move out, extend the shoulders, or use its back, especially for speed or jumping. It also prevents a horse from true elevation of the back needed for collection. A poorly-fitting Saddle (with an insufficiently high pommel arch or a narrow tree) may initiate or exacerbate this condition, as the horse will avoid movements which cause discomfort, thus leading to muscle loss behind the withers. Horses that trot fast with high, erect neck (like Standardbred race horses) do not develop strong, active back muscles. They are often hollow behind and just below withers due to lack of collection. This conformation is commonly rider-induced from a horse allowed to move strung-out behind, and is usually seen in gaited horses and long-distance trail or endurance horses. Protective movement by the horse to minimize saddle pinching may contribute to back pain. Persistent body carriage without collection can overuse some musculoskeletal structure, leading to arthritis. This conformation will not affect performance if saddle fits correctly. If the saddle does not, the horse is best used for non-speed and non-jumping sports.

High Withers

Withers Higher Than Croup

The 8th through 12th thoracic vertebrae are long and angle backward to create steep, high withers Especially seen in Thoroughbreds, Saddlebreds, and some Warmbloods. High withers provide a lever for the muscles of the back and neck to work together efficiently. As the head and neck lower to extend, the back and loin muscles correspondingly shorten or lengthen. The backward angle of withers is usually associated with sloping shoulders, which provides good movement of the shoulder blade. This makes it easy for the horse to engage in collection, lengthen, round its back for jumping, or extend its shoulder for improved stride length and speed. If the withers are too high and narrow, there is a chance that a poorly fit saddle will impinge on withers and slip back too far, creating pain especially with the rider's weight. Performance and willingness will suffer.


It is ideal to have a short top line in relation to a long underline.
Image/UDC Extension

Long Back

Slightly Long Back

With the back measured from peak of withers to peak of croup, exceeds 1/3 of horse's overall body length. Usually associated with long, weak loins. Especially seen in gaited horses, Saddlebreds, Thoroughbreds, and some Warmbloods. The horse's ability to engage back depends on its ability to elevate the back and loins, requiring strong back and abdominal muscles. A long back is flexible, but harder for horse to stiffen and straighten spine to develop speed or coil loins to collect and engage the hindquarters to thrust rear limbs forward. This then affects upper level dressage, cutting, reining, barrel racing, and polo: sports that require rapid engagement of the hindquarters. Reduced flexion forces the horse to jump flatter with less bascule. It is difficult to develop a long back's muscle strength, so a horse is more likely to fatigue under the rider and to sway over time. The abdominal have more difficulty in compensating, so they are also less likely to develop. Loins and hindquarters may swing more than normal, increasing the occurrence of sore muscles which leads to a stiff, rigid ride. Cross-firing or speedy cutting likely at high-speeds from a horse with a long back. Movement of the back is flatter and quieter, making a more comfortable ride and is easier for horse to change leads.

Short Back

The horse's back measures less than 1/3 of overall length of horse from peak of withers to peak of croup Can be seen in any breed, especially in American Quarter Horses, Arabians, and some Warmbloods The back may lack flexibility and become stiff and rigid. If vertebral spines of back are excessively small, the horse may have difficulty bending and later develop spinal arthritis. This adversely affects dressage and jumping performance. If still in back and torso, the stride will become stiff and inelastic. The horse may overreach, forge, or scalp itself if the hind legs do not move straight. The horse may be handy and agile, able to change direction with ease. Good for polo, roping, cutting, reining. If the horse has good muscling, it is able to support weight of rider with rare occurrence of back pain. Conformation best used in agility sports.

Sway Back Image: Wikipedia/Fair Use

The span of the back dips noticeably in center, forming a concave contour between the withers and croup. Usually causes high head carriage and stiffness through the back. Associated with a long back. Often associated with weakness of ligaments of the back. Examples include a broodmare who had multiple foals and the back dips with age, an old horse where age is accompanied with weakening of the ligaments, a horse with poor fitness/conditioning that prevents adequate ligament support of the back muscles, or an overuse injury to the muscles and ligaments from excess work, great loads, or premature work on an immature horse. Some horses with high croups and straight backs often appear to be swayed. Often accompanies long loins. If the loins are not broad, the ligament structures may weaken, causing the back to drop. A sway back positions the rider behind the center of gravity, interfering with balance. The horse is unable to elevate for true collection, which can affect any sport but most notably dressage, jumping, and stock work. The back may get sore from lack of support and the rider's weight. The horse is unable to achieve rapid impulsion since the rear is less connected with front end. To achieve speed, the horse must create some rigidity in back and spine, which is not possible with a sway. This causes problems in racing, eventing, Steeplechasing, and polo. This horse is most suited for pleasure riding and for teaching students. Although sway backs are usually associated with older horses, there is also a congenital (sometimes genetic) form of sway back. Horses with this condition will already be obviously swaybacked at a young age, sometimes even before they are a year old. Some lines of American Saddle Horse seem to carry this gene.

Loins and Coupling

Roach Backed

In the area where the back and loins join the croup (the coupling) there is an upward convex curvature of the spine. Often a result of a short back, or injury or malalignment of the lumbar vertebrae. Often accompanied by less-developed loin muscles in breadth, substance, and strength. The spine already "fixed" in a curved position, and the attaching muscles are unable to contract properly to round or elevate the back. Thus it is difficult to engage the hindquarters or round the back by elevating loin muscles. Vertebrae often have reduced motion so the horse takes shorter steps behind. Jumping and dressage especially are affected. The horse is stiffer through the back and less flexible in an up and down motion as well as side to side. There may be back pain from vertebral impingement. There is a less elastic feel beneath rider as the back too rigid. Agility sports (polo, cutting, reining, barrel racing, gymkhana) are more difficult.

Long Loins/Weak loins/Weak Coupling

Coupling is the joining of back at the lumbosacral joint. Ideally, the L-S joint should be directly over the point of hip. Weak coupling is where the L-S joint is further to the rear. The loins are the area formed from last rib to point of hip. Although normally only 2-3 fingers breadth, long loins have more than a hand's breadth. Long loins are associated with a long back. The croup is often relatively flat and the quarters are high. Horse with weak or slack loins might have good lateral bend, but collection suffers as true collection depends on coiling loins to bend the hind legs. Because the hind legs and hocks are not able to be positioned under body, the hind legs string out behind, so the horse is more likely to go on the forehand. This creates coordination and balance problems, as well as forelimb lameness. The horse needs the hind legs under for jumping, and for going up and down hill. Weak loins inhibit this, especially affecting eventing, jumping, and trail horses. The loins regulate the distribution of weight on the forehand by allowing the horse to elevate its back and distribute its weight to the hind end. Horses unable to coil the loins move with stiff backs and a flattened L-S joint, throwing the rear legs out behind. This limits the ability of dressage horses, and also affect reining, cutting, and polo horses as they are unable to explode with thrust.

Rough Coupling

In the loins, the horse has a hollow area considerably lower than foremost part of the croup. Fairly uncommon, and does not affect the horse's use in sport. Cosmetically displeasing. Muscling of loins may be ample and strong with minimal effect on ability to collect back or push with haunches. However, if a horse does not have strong loins, it will have difficulty in raising the back for engagement.

Croup and "hip"

The croup is from the lumbosacral joint to the tail. The "hip" refers to the line running from the ilium (point of the hip) to the ischium (point of the buttock)of the pelvis. While the two are linked in terms of length and musculature, the angle of the hip and croup do not necessarily correlate. A horse can have a relatively flat croup and a well-angled hip. Racehorses do well with hip angles of 20-30 degrees, trotting horses with 35 degrees.

Steep Croup or Goose Rump

A steep croup is often linked to shortened stride. Less of a fault for slow-moving horses such as draft breeds than for light riding horses.

High Croup

Flat Croup

The topline continues in a relatively flat manner to the dock of tail rather than falling off at oblique angle at the hips. Seen especially in Saddlebreds, Arabians, and Gaited horses. Encourages a long, flowing stride. This helps a horse go faster, especially when a flat croup is sufficiently long to allow a greater range of muscle contraction to move the bony levers of skeleton.

Short Croup

Length from L-S joint to dock of the tail is insufficient for adequate muscular attachment. Reduces power of hindquarters. Usually seen in conjunction with multiple hind leg faults.

Short "hip"

The L-S joint is often behind the point of hips. Insufficient length from point of hip to point of buttock. Horse will have difficulty collecting. A well-muscled build may hide a short pelvis. Provides less length of muscular attachments to the thigh and gaskin. This diminishes engine power in speed or jumping events. Short hip is less effective as a muscular lever for collection and to contract the abdominal muscles as the back rounds. More muscular effort is required.

Flat "hip"

Flat pelvis, line from point of hip to point of buttock flat and not properly angled, result is pelvis structure too long. L-S joint often tipped, ishium improperly placed. It is more difficult to engage the hindquarters, so the back tends to stiffen. Thus it is hard to excel in dressage, jumping, stock horse work. Minimizes the ability to develop power at slower paces needed by draft horses.

A "Jumper's Bump"

The horse has an enlargement at the top of the croup, or a malalignment of the croup with the pelvis and lumbar vertebrae, caused by the tearing of a ligament at the top of the croup. One or both sides of L-S joint may be affected. Fairly common, usually seen in jumping horses and in horses that rack in an inverted frame. It is a torn ligament caused by excessive hindquarter effort, or from a horse that had the hindquarters slip out underneath or trotted up a very steep hill. Usually does not cause problems once healed, although it is easier to re-injure. Usually associated with horses with weak loins or a long back that is unable to coil loins properly for collection. Commonly caused by overpacing young horses, a rider allowing a horse to jump while strung out, or by racking (or other gaiting) in a very inverted frame.


All About the Horse's Conformation/Part 1
All About the Horse's Conformation/Part 3

Medical Index