By John Pipkin

I consider four criteria when evaluating conformation: balance, structural correctness, quality/breed characteristics and muscling. I look for a horse that's the best combination of all four.

To assess balance, I first look to see if a horse's body ties together smoothly and proportionately. Then I mentally divide him into three sections: 1) from point of shoulder to heartgirth (behind the horse's shoulder); 2) from the heartgirth to the point of hip; and 3) from the point of hip to the tailhead. Ideally, these lengths will be equal.

I want a horse's neck to be long and lean, and I want him to have an equally sloped shoulder and hip. I also want him to have a level back, and for his withers and croup to be the same height. Structurally, he should exhibit upright, correctly aligned leg bones, and hocks with neither too little, nor too much angle.

For quality/breed characteristics, a horse's head should be short (from poll to muzzle) and proportionate, tapering at the muzzle for a chiseled appearance. His eyes should be large with a kind expression. He should also show his breed's ideal characteristics.

Then I evaluate muscling on volume (muscle amount), length (how far it extends to its connection point) and definition (tone and conditioning).

Click "Next" to find out how I placed these aged Quarter-type geldings.

First: Gelding C Of the three horses, this horse really has the greatest combination of balance, structural correctness, quality and adequate muscling. His biggest advantage over the second and third place horses is in his balance and the quality of his head and--especially--the quality of his neck. Compared to the other two horses, his neck is trimmer and ties in much higher at the base of the neck (where it ties into the shoulder and chest). Trimness reflects flexibility and functionality. A horse uses his neck as a leverage point, and a trim, thin, long, high-tying neck is a conformational advantage. This horse is also more structurally correct, especially down both front and hind legs, viewed from the side. Leg structure is the foundation for support and soundness. Viewing leg structure from the front and rear, I look for straight alignment--from point of attachment down through knee and hock, through the cannon bones, pasterns and toes. From the side, I look for a front leg with adequate angle in the arm (as it comes out of the shoulder), and extends down a straight column of bone. For cushion, shock absorption and stride, I like to see a 30- to 45-degree angle in pasterns (hopefully about the same as the shoulder angle). The hock should be properly placed so the cannon is upright and there's a correct angle in both the stifle and the hock--that'll allow for proper motion of the hind leg and a stride underneath the body. This horse also has an overall smooth blending appearance that reflects his balance. And good balance contributes to performance capabilities. He has a desirable shape to his head, which reflects adequate quality and breed characteristics, and he has an acceptable topline which contributes to his overall balance. Ideally he could be cleaner in his throatlatch, and I'd like to see him heavier muscled. Second: Gelding B The second and third place horses are a really close pair, in my mind. However, with an emphasis on the advantages in balance and structural correctness in the front leg, I placed this horse second. Specifically, this horse has more slope to his shoulder and is stronger behind his withers and in his back than the third place horse. From a functional standpoint, that reflects more strength in his overall topline--a definite conformational advantage. In addition, he appears longer in his hip, and from this photo it looks like he carries more substance of hindquarter down the longer hip. He's also somewhat trimmer in his throatlatch and neck. While neither horse ties in as high at the base of their neck as I like to see, the second place horse appears more correct down his front leg. Ideally, this horse would have a more refined head, his neck would tie in higher at the base of the neck, and he'd be straighter down his hocks when viewed from the side. Third: Gelding A While this horse has a nicer head and brighter appearance than the second place horse, he doesn't appear as structurally correct in his legs. He seems slightly back at the knee, which is undesirable from a conformational and functional standpoint. If you draw a plumbline down the side of his front leg, you'll see he's not as straight as the first two horses. A horse that's back at the knees can suffer from soundness issues because he can't absorb concussion as efficiently. I'd like to see him trimmer in the throatlatch, and ideally, his neck would tie into the shoulder higher. I'd also like to see a more level, stronger topline to allow for greater impulsion and collection. The two clear advantages this horse has over the second place horse is that again, he has a more attractive head, which tapers down his face to a more refined muzzle; and he's straighter down his hock from the side than the second place horse. John Pipkin, Ph.D., holds judges cards for the American Quarter Horse Association, American Paint Horse Association, National Reining Horse Association, National Reined Cow Horse Association, and National Snaffle Bit Association. He's judged nearly 300 shows nationally and internationally, including the AQHA Youth World Championship Show (twice), the APHA World Show, AQHA Amateur World Show (twice) and the APHA Youth World Show. Aside from judging, John is a professor at West Texas A&M University. This article originally appeared in the March 2007 issue of Horse & Rider magazine. Enter Your Horse in Conformation Clinic! To submit a photo of your horse to be evaluated in Horse & Rider's Conformation Clinic, send us a left-side view photo of your horse (for digital phots: high-resolution, 300 dpi, in at least 3" x 5"). Make sure he's well-groomed, looking straight ahead and standing on level ground--and try to avoid distracting backgrounds. Email amanda.peterson@equinetwork.com and include your contact info and your horse's breed, age, gender and height.

By Michael Damianos

As someone who rides performance horses, I'll always prefer a horse I think is usable, versus one that's "just a pretty horse." And I feel compelled to stick to the class specifications and criteria set forth by Arabian judging standards.

We have to consider a horse in this order: Arabian type, conformation, suitability as a breeding animal, quality, movement, substance, manners and presence.

So, as an Arabian judge, the first thing I evaluate is type, which is basically made up of the characteristics that distinguish an Arabian horse from other breeds. There are five main points of type: head, neck, back, croup and tail. Because the horses in these photos are standing still, it's difficult to judge criteria like movement, presence and tail carriage. But I'll evaluate suitability as a breeding animal because this is a class of mares. "Like breeds like," so to me, good conformation and type contribute to a horse's suitability for breeding.

Click "Next" to find out how I placed these three aged Arabian mares.

First: Mare C This mare's conformation far exceeds the second- and third-place horses, although she doesn't show as much Arabian type as the mare I placed second. She has a plainer head than the second-place horse, and she doesn't have a great neck, but it ties in to her shoulder better than the second-place mare. This mare and the second-place horse both have short cannons (which contributes to stamina and soundness). But this mare's shoulder angle (which improves elasticity and movement) and the ratio of her shorter topline (from withers to croup) to her longer underline (point of elbow to stifle) are the best of the three, which gives her the best balance in this class. I would, however, like her to have a little more angle to her pasterns for better shock absorption and soundness. While I can't judge movement from a photo, I can make some assumptions by studying her body angles and leg structure. Based on those, I'd expect this mare to be the best mover of the class. She has good hip angulation and overall balance, which suggest it'll be easiest for her to hold up to the rigors of performance. Second: Mare B This mare is the typiest of the three. If you stood back and looked at all three mares, this is the mare you'd most readily identify as an Arabian. She has a slightly concave (dished) face, and the shortest distance between eye and muzzle of the other two mares in the class. She has good angulation from the point of her hip to the point of her buttocks, however, her neck doesn't set well back into her withers, and she has an average back. Her topline-to-underline ratio isn't as good as the first-place mare, but I wouldn't say it's bad. She also has the most horizontal croup of the three horses, which is a type characteristic for Arabians. This mare has the best angle to her hip, but it appears (at least in this picture) that she camps out behind--if you dropped a plumbline from the point of her buttocks, the mare's hocks and fetlocks would stand behind that line. Because she's camped out behind (which will make it more difficult for her to engage her hindquarters) and she has a steep shoulder, she probably won't be the athlete that the first-place horse may be. Third: Mare A Based on the photo, this mare doesn't appear to have much Arabian type. I placed her third because of her lack of typiness and her less desirable conformation. She has a borderline ewe neck (the neck bends upward rather than arching down, which can make collection difficult), and she has a long back in relation to her underline (a ratio of 1:2 is preferred for the length of the topline to the underline). That ratio is an important indicator of balance and athleticism. Her face is long, but on the positive side, it looks like she has the shortest ears in the class. She has a short and borderline "rafter-type" hip (a flat hip, shaped like a "T" from behind), both of which can make it more difficult for her to collect and work from behind. Her long cannon bones could make her more susceptible to injury. She doesn't have good muscling, her joints are small, and her body conformation is not well-balanced, all of which tell me she'll have to work a lot harder than a well-conformed horse, and may have difficulty holding up to the demands of performance work. Michael Damianos operates Michael Damianos Performance Horses at Starbuck's Ojai Valley Ranch in Ojai, Calif., where he lives with his wife, Dawn, and daughters. A trainer for 25 years, he trains and shows Arabian performance horses at the regional and national level in Western pleasure, reining, trail, driving, and English classes, and coaches youth and amateur riders. He's a carded judge for the Arabian Horse Association, AQHA, ApHC, APHA, NRHA, NRCHA and NSBA. This article originally appeared in the September 2007 issue of Horse & Rider magazine. Enter Your Horse in Conformation Clinic! To submit a photo of your horse to be evaluated in Horse & Rider's Conformation Clinic, send us a left-side view photo of your horse (for digital phots: high-resolution, 300 dpi, in at least 3" x 5"). Make sure he's well-groomed, looking straight ahead and standing on level ground--and try to avoid distracting backgrounds. Email amanda.peterson@equinetwork.com and include your contact info and your horse's breed, age, gender and height.

By Darrell Bilke

I look at balance, eye appeal and breed character--I want a horse to look nice. Next I'll look at soundness and structural correctness. I'll start at the head and want to see that he has a nice, kind eye, a little fox ear, and that his head is in balance from the eye to the point of nose, and to the muzzle. I want to see a clean throatlatch, a head that ties in nicely to the neck, and a neck that ties in well to a long, sloping shoulder.

For balance, I look for shortness of back compared to the underline, and a long croup that carries down deep into the stifle, with good gaskin muscling. I like to see good depth of heartgirth.

And then I'll assess straightness and how the horse travels. All four legs need to be correct--just like a car can't run on three tires, a horse needs to have four legs that are structurally sound.

Click "Next" to find out how I placed these three 3- and 4-year-old Quarter Horse geldings.

First: Gelding C
I placed this bay gelding first because he exhibits the best balance, eye appeal, breediness and structural correctness of the three. Starting at his head, he has a soft, kind eye, nice fox-like ears placed well on his head, and a clean throatlatch. His head sets well on a clean neck that connects correctly into a nicely sloped shoulder. The muscling in his shoulder ties down deep and well into his forearm, and his legs appear straight and sound, with a correct, clean front end. He's got a good set of withers, a nice short back compared to the length of his underline, and a lot of depth to his heartgirth. All of that tells me he'll be able to lift his front end and work off his hindquarters.

The one area where I'd like to strengthen him a little is in his croup, but it's adequate and carries into the stifle and gaskin muscle, then down deep into his hind legs. His hocks are a little hard to see, but they're down where they belong so he can get under himself and handle himself. When this horse is jogging and loping he'll be able to stick his hind leg under himself, and when his front foot leaves the ground, his hind leg will reach forward and his hind foot will step right into the same place. He's balanced and should be a nice horse to ride.

Second: Gelding A
This horse and the third-place horse are a close call, but I chose this horse ahead of the other because he looks like he'll be a better mover. These horses are geldings, which means we're going to be riding them, and I chose this horse because his conformation tells me he'll be sounder and more athletic than the third-place horse.

He's a nicer-headed horse than the third-place horse, and while I'd like to see a longer, cleaner neck on him, his topline is shorter in relation to his underline when compared to the number three horse. Because of his shorter back, its ratio to his underline (you want to see a 1:2 ratio for length of back to length of underline), the depth of heartgirth and where his hock is, he'll probably be a better mover than the number three horse. He has a little more substance, and nicer, flatter bone than the sorrel horse. I suspect he won't face the soundness issues the third-place horse might have. I like him better in the shoulder and withers, too. Again, they're a close pair, and I'm going to pick the one that fits my needs best. If I had to pick one to play in the roping pen, I'd pick this dun over the sorrel.

Third: Gelding B
I placed this horse third because he lacks the balance, structural correctness and breediness I like to see. He's light in the shoulder, with not nearly the muscling of the first two horses. He does have a nice, clean neck that comes out of his shoulder well, and he has a clean throatlatch--he should be able to flex well at the poll. But he's long-headed from his eye to the point of his muzzle, which contributes to a plain head. If you compare his ear placement to the ears of the other two horses, his ears are setting a little forward. I'd like to see this horse with a little more bone and substance.

Moving to his hind end, he's shortcrouped, and just looking at the way he's made I'd guess he's a little base-narrow and weak in the front end. He'll have a much harder time working with his hind-end underneath him. I'd also like to see more muscling. He doesn't appear as structurally correct as the others, and he may toe out, based on the positions of his ankles and hocks in the photo.

Darrell Bilke has been judging horses for more than 30 years, and holds some 15 judges cards, including more than 20 years judging for the American Quarter Horse Association and the American Paint Horse Association. Bilke has judged all major world shows, including the AQHA, APHA, and ApHC world shows, and has presided over Australian and European championships. Bilke owns and operates Bilke Enterprises in Miami, Okla.

This article originally appeared in the June 2007 issue of Horse & Rider magazine.

Enter Your Horse in Conformation Clinic!

To submit a photo of your horse to be evaluated in Horse & Rider's Conformation Clinic, send us a left-side view photo of your horse (for digital phots: high-resolution, 300 dpi, in at least 3" x 5"). Make sure he's well-groomed, looking straight ahead and standing on level ground--and try to avoid distracting backgrounds.

Email amanda.peterson@equinetwork.com and include your contact info and your horse's breed, age, gender and height.

Conformation Components

Excerpt from
Horse for Sale, How to Buy a Horse or Sell the One You Have
by Cherry Hill © 1995

Balance

A well-balanced horse has a better chance of moving efficiently with less stress. Balance refers to the relationship between the forehand and hindquarters, between the limbs and the trunk of the body, and between the right and the left sides of the horse.

The center of gravity is a theoretical point in the horse's body around which the mass of the horse is equally distributed. At a standstill, the center of gravity is the point of intersection of a vertical line dropped from the highest point of the withers and a line from the point of the shoulder to the point of the buttock. This usually is a spot behind the elbow and about two thirds the distance down from the topline of the back.

Although the center of gravity remains relatively constant when a well-balanced horse moves, most horses must learn to rebalance their weight (and that of the rider and tack) when ridden. In order to simply pick up a front foot to step forward, the horse must shift his weight rearward. How much the weight must shift to the hindquarters depends on the horse's conformation, the position of the rider, the gait, the degree of collection, and the style of the performance. The more a horse collects, the more he steps under his center of gravity with his hind limbs.

If the forehand is proportionately larger than the hindquarters, especially if it is associated with a downhill topline, the horse's center of gravity tends to be forward. This causes the horse to travel heavy on his front feet, setting the stage for increased concussion, stress, and lameness. When the forehand and hindquarters are balanced and the withers are level with or higher than the level of the croup, the horse's center of gravity is located more rearward. Such a horse can carry more weight with his hindquarters, thus move in balance and exhibit a lighter, freer motion with his forehand than the horse with withers lower than the croup.

When evaluating yearlings, take into consideration the growth spurts which result in a temporarily uneven topline. However, be suspicious of a two-year-old that show an extreme downhill configuration. Even if a horse's topline is level, if he has an excessively heavily muscled forehand in comparison to his hindquarters, he is probably going to travel heavy on the forehand and have difficulty moving forward freely.

A balanced horse has approximately equal lower limb (front) length and depth of body. The lower limb length (chest floor to the ground) should be equal to the distance from the chest floor to the top of the withers. Proportionately shorter lower limbs are associated with a choppy stride.

The horse's height or overall limb length (point of withers to ground) should approximate the length of the horse's body (the point of the shoulder to the point of buttock). A horse with a body a great deal longer than its height often experiences difficulty in synchronization and coordination of movement. A horse with limbs proportionately longer than the body may be predisposed to forging, over-reaching and other gait defects.

When viewing a horse overall, the right side of the horse should be symmetric to the left side.

Proportions and Curvature of the Topline

The ratio of the topline's components, the curvature of the topline, the strength of loin, the sharpness of withers, the slope to the croup, and the length of the underline in relation to the length of back all affect a horse's movement.

The neck is measured from the poll to the highest point of the withers. The back measurement is taken from the withers to the loin located above the last rib and in front of the pelvis. The hip length is measured from the loin to the point of buttock.

A neck that is shorter than the back tends to decrease a horse's overall flexibility and balance. Be sure to look at the neck from both sides because the mane side often appears shorter than the non-mane side. A back that is a great deal longer than the neck tends to hollow. A very short hip, in relation to the neck or back, is associated with lack of propulsion and often a downhill configuration. A rule of thumb is that the neck should be greater than or equal to the back and that the hip should be at least two-thirds the length of the back.

The neck should have a graceful shape that rises up out of the withers, not dip downward in front of the withers. The upward curve to the neck should be more pronounced in a dressage prospect than in a hunter or western prospect. The shape of the neck is determined by the S shape formed by the seven cervical vertebrae. A longer, flatter (more horizontal) configuration to the upper vertebrae results in a smoother attachment at the poll (as if the neck is behind the skull or the head is attached on the end of a flexible balancing arm) and results in a cleaner, more supple throat latch. If the upper vertebrae form a short, diagonal line to the skull, it is associated with an abrupt attachment (as if the neck attaches below the skull or the head is stuck on top of the neck) resulting in a thick throat latch, lack of flexibility, and possibly a hammerhead.

The curve to the lower neck vertebrae should be short and shallow and attach relatively high on the horse's chest. The thickest point in the neck is at the base of the lower curve. Ewe necked horses often have necks that have a undesirable long, deep lower curve and attach low to the chest. The attachment of the neck to the shoulder should be smooth without an abnormal dip in front of the shoulder blade.

The upper neck length (poll to withers) should be at least twice the lower neck length (throat latch to chest). This is dictated to a large degree by the slope of the shoulder. A horse with a very steep shoulder has an undesirable ratio (approaching 1:1) between the upper neck length and lower neck length. The more sloping the shoulder, the longer the neck's top line becomes and the shorter the neck's underline. The muscling of the topline of the neck should be more developed than the muscling of the underside of the neck. A thick underside to the neck is associated with a horse that braces against the bit and hollow's the neck's top line.

The back should look like it has a natural place for a saddle beginning with prominent withers that are located above or slightly behind (but not exaggeratedly in front of) the heart girth. The heart girth is the circumference of the barrel just behind the front limbs. The withers should gradually blend into the back ideally ending just in front of the midpoint of the back. The withers provide a place for the neck muscles and ligamentum nuchae to anchor and they should attach at the highest point of the withers; there should not be a dip in front of or behind the withers.

The withers also act as a fulcrum. As a horse lowers and extends its neck, the back rises. Low, mutton withers limit a horse's ability to raise his back. A horse with a well-sloped shoulder usually has correctly-placed withers. The heart girth should be deep which indicates adequate room for the heart and lungs.

The muscles that run alongside the spine should be flat and strong rather than sloped or weak. The back muscles must help counteract the gravitational pull from the weight of the horse's intestines as well as support the rider's weight. The line of the back should be flat or level, not hollow (dipped or concave) or roached (bowed up or convex). A hollow back is associated with weakness and a roached back with stiffness.

The loin is located along the lumbar vertebrae from the last rib-bearing (dorsal) vertebrae to the lumbosacral joint. The loin should be well muscled and relatively short. Horses termed "long-backed" often have an acceptable back length but a long, weak loin. A horse with a weak and/or long loin and loose coupling tends to have a hollow back. (The coupling is the area behind the last rib and in front of a vertical line dropped from the point of hip.) A horse that chronically hollows its back may be predisposed to back problems.

The loin and the coupling are what transfer the motion of the hindquarters up through the back and forward to the forehand, so they must be strong and well connected. A short, heavily muscled loin has great potential strength, power, and durability yet could lack the flexibility that a more moderately muscled loin may have. Loin muscling (best viewed from the top) should appear springy and resilient not stiff and cramped or weak and saggy. A lumpy appearance in the loin area may indicate partial dislocations of the vertebrae.

The croup is measured from the lumbosacral joint (approximately indicated by the peak above and slightly behind the points of hip) to the tail head. The croup should be fairly long as this is associated with a good length to the hip and a desirable, forward-placed lumbosacral joint. The slope to the croup will depend on the breed and use. Quarter Horses and Thoroughbreds traditionally have round croups; Arabs and Warmbloods have flat croups.

The topline should be "short" relative to the underline. Such a combination indicates strength plus desirable length of stride.

Head

The head should be functionally sound. The brain coordinates the horse's movements, so adequate cranial space is necessary. The length from the base of the ear to the eye should be at least 1/3 the distance from ear to nostril. The width between the eyes should be a similar distance as that from the base of the ear to the eye. A wide poll with ears far apart is associated with the atlas connecting behind the skull rather than below it. A wide open throat latch allows proper breathing during flexion; a narrow throat latch is often associated with a ewe-neck attachment. Eyes set off to the side of the head allow the horse to have a panoramic view. The eye should be prominent without bulging. Prominence refers to the bony eye socket, not a protruding eyeball. The expression of the eye should indicate a quiet, tractable temperament.

The muzzle can be trim, but if it is too small, the nostrils may be pinched and there may be inadequate space for the incisors resulting in dental misalignments. The incisors should meet evenly with no overhang of the upper incisors (parrot mouth) or jutting out of lower incisors. The width of the cheek bones indicates the space for molars; adequate room is required for the sideways grinding of food. The shape of the nasal bone and forehead is largely a matter of breed and personal preference.

Quality

Quality is depicted by "flat" bone (indicated by the cannon bone), clean joints, sharply defined (refined) features, smooth muscling, overall blending of parts, and a fine, smooth hair coat. "Flat" bone is a misnomer because the cannon bone is round. Flat actually refers to well-defined tendons that stand out cleanly behind the cannon bone and give the impression the bone is "flat".

Substance refers to thickness, depth, and breadth of bone, muscle, and other tissues. Muscle substance is described by type of muscle, thickness of muscle, length of muscles, and position of attachment. Other substance factors include weight of the horse, height of the horse, size of the hoofs, depth of the heart girth and flank, and spring of rib.

Best viewed from the rear, spring of rib refers to the curve of the ribs; a flat-ribbed horse may have inadequate heart and lung space. Besides providing room for the heart, lungs, and digestive tract, a well-sprung rib cage provides a natural, comfortable place for a rider's legs. A slab-sided horse with a shallow heart girth is difficult to sit properly; an extremely wide-barreled horse can be stressful to the rider's legs.

Substance of bone indicates adequacy of the ratio of the bone to the horse's body weight. Bone measurement is taken on an adult horse around the circumference of the cannon bone just below the knee. For riding horses, an adequate ratio is approximately .7 inches of bone for every 100# of body weight. Using that thumb rule, a 1200 # horse should have an 8.4 inch circumference cannon bone for his weight to be adequately supported.

Correctness of Angles and Structures The correct alignment of the skeletal components provides the framework for muscular attachments. The length and slope to the shoulder, arm, forearm, croup, hip, stifle, and pasterns should be moderate and work well together. There should be a straight alignment of bones and large clean joints when viewed from front and rear.

Forelimbs

Both forelimbs should appear to be of equal length and size and to bear equal weight. A line dropped from the point of the shoulder to the ground should bisect the limb. The toes should point forward and the feet should be as far apart on the ground as the limbs are at their origin in the chest. (See Movement for deviations) The shoulder should be well-muscled without being heavy and coarse.

The muscles running along the inside and outside of the forearm should go all the way to the knee, ending in a gradual taper, rather than ending abruptly a few inches above the knee. It is generally felt that this will allow the horse to use its front limbs in a smooth sweeping, forward motion. The pectoral muscles at the horse's chest floor (an inverted V) should also reach far down on to the limb. These and the forearm muscles help a horse move its limbs laterally and medially as well as to elevate the forehand.

Front limbs, when viewed from the side should exhibit a composite of moderate angles, so that shock absorption will be efficient. The shoulder angle is measured along the spine of the scapula from the point of the shoulder to the point of the withers. The shorter and straighter the shoulder, the shorter and quicker the stride and the more stress and concussion transmitted to the limb. Also important is the angle the shoulder makes with the arm (which should be at least 90 degrees) and the angle of the pastern.

The length of the humerus (point of shoulder to the point of elbow) affects stride length. A long humerus is associated with a long reaching stride and good lateral ability; a short humerus with a short choppy stride and poor lateral ability. The steeper the angle of the humerus, generally, the higher the action; the more toward horizontal, the lower the action.

To evaluate the medial-lateral slope of the humerus from the front, find the left point of shoulder and (a spot in front of) the left point of elbow. Do the same on the right side. Connect the four points. If the resulting box is square, the humerus lies in an ideal position for straight lower limbs and straight travel. If the bottom of the box is wider, the horse may toe in and travel with loose elbows and paddle. If the bottom of the box is narrower, the horse will likely toe out, have tight elbows and wing in.

The way the shoulder blade and arm (humerus) are conformed and attach to the chest dictate, to a large degree, the alignment of the lower limbs. Whether the toes point in or out is often a result of upper limb structures. That is why it is dangerous in many cases to attempt to alter a limb's structure and alignment through radical hoof adjustments. When assessing the lower limbs, be sure the horse is standing square.

The knees should be large and clean, not small and puffy. The bone column should be functionally straight and sound, not buck-kneed (over-at-the-knee) or calf-kneed (back-at-the-knee). The calf-kneed horse suffers strain at the back of the knee and concussion at the front of the knee which can result in carpal chips and other problems. The buck-kneed horse is unstable as the knees shake and are on the verge of buckling forward.

The flexor tendons running behind the cannon bone should be even and straight, not pinched in (tied-in) at the back of the knee or lumpy (indicating possible bowed tendon) anywhere from the knee to the fetlock.

Normal front pastern angles range from 53 to 58 degrees. Exceptionally long, sloping pasterns can result in tendon strain, bowed tendon, and damaged proximal sesamoids. Short, upright pasterns deliver greater concussive stresses to fetlock and pastern joints which may result in osselets, ringbone, and possibly navicular syndrome. Fetlock joints should be large enough to allow free movement but they should be devoid of any puffiness. The hoof should be appropriate for the size of the horse, well-shaped and symmetric with high quality hoof horn, adequate height and width of heel, and a concave sole. The hoof angle should be the same as the pastern angle making a smooth continuous line. For more information on hoof conformation and management see

Maximum Hoof Power

(http://www.horsekeeping.com/horse_books/Maximum_Hoof_Power.htm)

Hind limbs

The bone structure and muscling of the hind limb should be appropriate for the intended use. Endurance horses are characterized by longer, flatter muscles; stock horses by shorter, thicker muscles; all-around horses by moderate muscles.

Hind limbs, when viewed from the side should exhibit a composite of moderate angles, so that shock absorption will be efficient. A line from the point of buttock to the ground should touch the hock and end slightly behind the bulbs of the heels. A hind limb in front of this line is often sickle hocked; a hind limb behind this line is often post-legged or camped out.

The hindquarter should be symmetric and well connected to the barrel and the lower limb. The gluteals should tie well forward into the back. The hamstrings should tie down low into the Achilles tendon of the hock.

The relationship of the length of the bones, the angles of the joints, and the overall height of the hind limb will dictate the type of action and the amount of power produced. The length and slope to the pelvis (croup) is measured from the point of hip to the point of buttock. A flat, level croup is associated with hind limb action that occurs behind the hindquarters rather than underneath it. A goose rump is a very steep croup that places the hind limbs so far under the horse's belly that structural problems may occur due to the over-angulation.

A short femur is associated with the short, rapid stride characteristic of a sprinter. A long femur results in a stride with more reach. High hocks are associated with snappy hock action and a difficulty getting the hocks under the body. Low hocks tend to have a smoother hock action and the horse usually has an easier time getting the hocks under the body. The gaskin length (stifle to hock) should be shorter than the femur length (buttock to stifle). A gaskin longer than the femur tends to be associated with cow hocks and sickle hocks.

Hind limbs with open angles (a "straighter" hind limb when viewed from the side) have a shorter overall limb length and produce efficient movement suitable for hunters or race horses. Hind limbs with more closed joints (more angulation to the hind limb) have a longer overall limb length and produce a more vertical, folding action necessary for the collection characteristic of a high level dressage horse. If the overall limb length is too long, however, it can be associated with either camped out or sickle hocked conformation. No matter what the hind limb conformation is at rest, however, it is the way which it connects to the loin and operates in motion that is most important.

From the rear, both hind limbs should appear symmetric, to be of the same length and to bear equal weight. A left to right symmetry should be evident between the peaks of the croup, the points of the hip, the points of the buttock, and the midline position of the tail. The widest point of the hindquarters should be the width between the stifles. A line dropped from the point of the buttock to the ground will essentially bisect the limb but hind limbs are not designed to point absolutely straight forward. It is necessary and normal for the stifles to point slightly outward in order to clear the horse's belly. This causes the points of the hocks to face slightly inward and the toes to point outward to the same degree. The rounder the belly and/or the shorter the loin and coupling, the more the stifles must point out so the more the points of the hocks will appear to point inward. The more slab-sided and/or longer coupled a horse, the more straight ahead the stifles and hocks can point. When the cannon bone faces outward, the horse is often cow-hocked; when cannons face inward, bow-legged.

Soundness problems can occur when the hocks point absolutely straight ahead and the hooves toe out; then there is stress on the hock and fetlock joints. The hind feet should be as far apart on the ground as the limbs are at their origin in the hip. Normal pastern angles for the hind range from 55 to 60 degrees.

http://www.horsekeeping.com/horse_conformation/components.htm
QUESTION

Subj: Gait of Foxtrotters
Date: 98-04-14 18:21:47EDT
From: TRVNKNLS
To: MFTHorses

Perhaps you could direct this question to Ms. Zeigler, who seems to have lots of knowledge on horse gaits, etc. A recently published article on Foxtrotting show horses said that when the show Foxtrotter walks, and foxtrots, it does not bend at the knee. Is that possible ? It seems that a stiff front leg would not give as smooth a ride, and would also subject those horses to be "stumbley" on the trail, or flat dangerous in rough terrain. It seems that in the long run, this type of movement would be detrimental to the breed as a trail and pleasure riding horse. Your thoughts....

ANSWER

In answer to the question on bending the knee at the fox trot. Of course they bend at the knee, they could not move their legs if they did not! I believe that what the writer was trying to say was that Fox Trotters do not have high knee action, and tend to reach "out" rather than "up" with their front legs. This type of leg use in front is different from that of the typical Tennesee Walker or Saddlebred, for example, but similar to that of a Tbred or good moving Quarter Horse.

For this reason, good conformation in the front quarters of a Fox Trotter should include a long, well sloped shoulder and a long, more horizontal than vertical humerus. This predisposes to reach rather than action. In a TWH, however, an upright shoulder and more vertical humerus are desireable because they will predispose to high, short action in front.

The humerus bone is; " the bone running from the front point of the shoulder to the elbow"

Hope this answers the question.

Lee Ziegler

http://www.leeziegler.com



Croup. The croup is of fundamental importance in animal mechanics, because it is the corner-stone of the transmission of the posterior impulse (hocks) to the anterior, and its inclination (according to the axis of the coxa) is directly correlated to the length of the posterior muscles (gluteals and ischeo-tibials) and hence to their angulation. In fact, the femur forms an angle with the coxa which varies from 90° to 120°, and since the metatarsal is always perpendicular to the ground, it is obvious that the inclination of the thigh (femur) and leg (tibia) will depend upon the slope of the croup. We will discuss this further in the section on hindquarters.  

A horizontal croup, typical of gallopers, presupposes long ischio-tibial muscles with a consequently greater ability to contract, and thus an ample oscillation of the limbs. An inclined croup, typical of trotters, presupposes shorter muscles. In the Cane corso the croup is slightly inclined: in fact, its typical gait is a lengthened trot.  

The croup should be long, because it acts as the fulcrum of transmission; the efficiency of action is in relation to its length.  

The width of the croup is in relation to the schelectric construction, and consequently to the development of the muscular mass. The croup of the Cane Corso must be broad because he must develop more power than speed.  

A serious fault is a steep croup (over 35°) since it means an insufficiently angulated posterior, caused by the shortening and weakening of the ischio-tibial muscles; the dog, to avoid fatigue, puts one bone radius over the other as vertically as possible with incorrect articulation of the coxo­femural and the knee. This pathology often goes with a croup which is higher than the withers and with an excessive weight on the anterior, causing a difficult and clumsy movement. Just as bad but rarer is a horizontal croup (under 15°) which determines a femur-tibial straightening and angles which are too open (If this is associated with a short croup, movement is seriously limited).  

Tail. When the Cane Corso relaxes his tail it should look like the backbone of a fish. Being wide at the root and narrowing toward the end, the adipose tissues which cover the caudal vertebrae, resting on the buttocks, give it this characteristic "V" shape. A low-set tail usually goes with a sloping croup. If the tail is too narrow at the root it will be held candle-like in action, and this too should be penalized.

http://www.deucalions.com/standard_comments.htm

The Horse’s Back and BTB

There are some things that, once said, seem so fundamentally obvious that you have to wonder why they aren’t uppermost in your mind all the time and why you might ever need reminding, and here to start this article is one; the back is the most important structure in the ridden horse.

 Horses can, and do, perform remarkably well with sore feet, which is probably just as well given the trauma of shoeing. Back pain is another thing entirely and is quite capable of turning the most mild mannered and willing of horses into a bad tempered and uncooperative lout. And who can really blame them? But, unlike the foot, which is relatively simple by comparison, the back is complexity itself. It’s only in the last few years that studies of the spine have come along, primarily due to the development of technologies that allow 3D imaging of its structures while in movement and under loading.

But if this complexity prevents the average owner from a detailed knowledge of spinal structure and operation there have to be some basics that we all take on and keep firmly in mind, since they impact heavily on our ability to maintain the horse’s wellbeing during work. And, if you are wondering where the ‘BTB’ (bitless-treeless-barefoot) comes into this then wonder no more. Bitless bridles, treeless saddles and barefoot trimming are all attempts to address problems caused by our use of horses, and each impacts on the operation of the back.

We may make a primary connection between bitless bridles and the mouth, but any pain caused directly in that area is really of secondary importance; what is of greatest concern is the impact on the back, and therefore the whole musculo-skeletal structure of the horse, as the horse attempts to avoid such pain, and the postural changes it goes through in the process.  

We’ve touched on this before, but not in any detail, so perhaps we should go over the ground again as part of building up a holistic approach to what we put on our horses and what we ask of them once we have. Rather than describe the movement sequences in each of the four paces – walk, trot, canter and gallop – I’ve taken some ‘licence’ in coming up with a way of describing a composite of movement for the sake of discussion – so I hope purists will pardon the generalisations! And just so we keep a broadly scientific grounding throughout I’ve added quotes from scientific papers that have dealt with these issues.

First of all there have been several attempts to develop a diagram illustrating the basic design concept of the horse’s back; below is the most recent and generally considered to be most accurate. 

This is known as the bow and string model, and although it may look a little complicated the principles are fairly straightforward.

The bow equals the spine between wither and tail and this, as is shown, is naturally braced in a convex curve, while the string roughly approximates the belly line. The sternum and abdominal muscles act to support the downward force on the belly, while the abdominal viscera pull down against the string. The epaxial musculature (def: above the axis of the spine) also exerts a downward or flattening effect. The muscles that extend the foreleg, or the protractors, exert downward pressure on the bow, while those that pull the foreleg back, the retractors, exert upward pressure – while with the hindleg this action is reversed.

 So far so good – but we now have to add a further complication with the effect of head and neck. First we’ll look at flexion.

As the head is lowered the ligaments that run from head to tail tighten, supporting the back;  the foreleg swings forward (protract) and propulsion from the hindleg is transferred via the hip along the spine.

The head raises, ligament lengthens allowing foreleg to swing back (retract) and hindleg to swing forward. 

So we have a constant cycle of flexion and extension while the horse is moving – but this only deals with the movement of the spine as if the horse’s body is in a straight line travelling over perfectly flat ground with no irregularities. In reality, horses are rarely, if ever, so straight, and ground surfaces, even those that appear quite flat have any number of minor or major irregularities. The vertebrae allow the horse to harmonise with the ground surface by rotating in 3 dimensions.

With the healthy horse in free action these forces flow through the spine to produce that beautiful harmony of movement and speed that we so admire – but in the ridden horse there are extra forces at play that are not part of the natural design concept and can have a major impact.

So let’s go through flexion and extension again with rider weight added. We’ll say that rider weight is, in this case, not extreme as a percentage of the horse’s own body weight, that the horse is reasonably fit and has been given reasonable preparation before being asked to perform under this extra burden, and let’s assume that we won’t cause too much of a problem.

During flexion the tightening of the ligaments supports the back against the downward pressure of rider weight, but at extension the back is less well supported and rider weight impacts more heavily making it more difficult to retract the foreleg and bring the hindleg forward under the body ready for the next flexion phase.

• The movements of the back directly influence the head and neck position. With a high head and neck position, the stride length and extension of the back are significantly reduced. The neck can be a useful measure of stretch through the back as well as stride length. ( Rhodin, M., Johnston, C., Holm, K.R., Wennerstrand, J. and Drevemo, S. (2005) The influence of head and neck position on kinematics of the back in riding horses at the walk and trot. Equine Vet J 37, 7-11.)

If we now consider the same situation, but with a heavy rider, it becomes very clear that the spine will be operating under far greater stress. There is no question that such a horse will tire more rapidly and will be more likely to stumble as the energy required to bring hindleg forward and retract foreleg is increased. But we have only just begun to consider the interference we impose – at this point our model is working with neither bridle and bit nor saddle – so let’s add those in next.

Bit and bridle first, and we’ll assume that not only is our rider a good weight for the size of the horse but that they are fit and well trained. So what we are really assuming here is that the combination of bit, bridle and rider are having no effect on the movement, and are merely following it with the lightest of contact. But what if our rider is not quite fit or well trained? During flexion the head, instead of being able to move freely forward and down, has to drag the weight of the rider’s hands, arms and upper body forward while at the same time supporting, in fact actively lifting, the extra weight. As the extension phase occurs, the rein contact changes, requiring some adjustment in gait. Our rider shortens the loosened reins just in time for the head to go forward again, and instead of the head being able to go smoothly down and forward it is checked with an increase in pressure on the tissue of the mouth and gums. In an effort to adapt to these changes the muscular tension increases, the process becomes more tiring still, and the flow of one phase into another is less smooth. No doubt there is also an element of irritation involved, as the horse is well aware of how easy the same movement is without rider interference.

• Movement of the back at the wither is significantly reduced in the ridden horse (Townsend, H.G., Leach, D. and Fretz, P.B. (1983): Kinematics of the equine thoracolumbar spine. Equine vet. J. 15, 117-122.) 

Now add a rigid saddle.  

• Without a rider, the saddle still exerts force, due to vertical acceleration - particularly in trot where it shows a marked up / down motion. (Peham, C. and Schobesberger, H. (2004) Influence of the load of a rider or of a region with increased stiffness on the equine back: a modelling study. Equine vet. J. 37, 703-705.)

Obviously there is a question of added weight, but on top of that the points of the tree impede the free movement of the shoulders and tend to dig in or at the very least cause a pulse of increased pressure when the back is least supported at the start of extension.  

• Tree pressure points can cause pain, muscle wastage, problems related to the willingness of the horse to be ridden, moving the back away from the underneath of the saddle, stiffness in lateroflexion, dorsoflexion, and ventroflexion, and difficulties in transitions as well as in collection. (Nyikos, S., Werner, D., Müller, J. A., Buess, C., Keel, R., Kalpen, A., Vontobel, H. D., Plocki, K. A. von, Auer, J. A., Rechenberg, B. von (2005) Measurements of saddle pressure in conjunction with back problems in horses. (Pferdeheilkunde, 2005 (Vol. 21) (No. 3) 187-198Nyikos at al., 2005.)
 

As the vertebra rotate in order to compensate for unevenness in the ground surface they are either restricted by the rigidity of the saddle or buffeted by increased contact and pressure between back and underside of the saddle – and if we then put our heavy rider back on the model, give them poor rein contact and an uncomfortable bit, we have all the components of a potentially miserable experience for the horse.

• The range of motion of the ridden horse is significantly lower than that of the unridden horse. If a saddle provokes localized pressure concentrations, the horse terminates the forward swing of the leg and stride length decreases. (Peham, C. and Schobesberger, H. (2004) Influence of the load of a rider or of a region with increased stiffness on the equine back: a modelling study. Equine vet. J. 37, 703-705.)

And if that was not enough, we’ll also fix rigid metal shoes that alter the nature of the foot’s impact with the ground, the potential for the toe to cut in and greatly reduce shock-absorption and the safe distribution of heat away from the concussive surface, and there is absolutely no surprise that we might easily exceed the tolerance of the structure – with back ache, overflexion of joints and lameness the outcome. But even if none of those happen and the structure is not clinically damaged we can expect the living creature that inhabits our model to be less than enthusiastic about performing.

• The influence of a saddle with weight can best be described as an overall extension or hollowing of the back. This may contribute to soft tissue injuries and Kissing Spines Syndrome. (DeCocq, P., van Weeren, P.R. and Back, W. (2004) Effects of girth, saddle and weight on movements of the horse. Equine vet. J. 36, 758-763.)

No wonder then that they attempt to take control of the bit, or fight its pressure. The rider might think they are pretty stupid to do so and that all they have to do is relax and stop pulling for comfort to return – but the horse knows too well that it was discomfort that made him try to take back the control over his own body that he is used to having when this damned lump is not in his mouth and on his back!

• A kind horse may become awkward and rather fractious. This may be seen as a loss of enthusiasm for work. There may be a disinclination to jump, particularly the combination-type fences…or a horse may lose its fluidity and timing and tend to rush his fences. (Jeffcott, L. B., 1975: The diagnosis of diseases of the horse's back. Equine Vet. J. 7, 69-78. 1975)

Having gone through this over-view process let’s now bring the discussion around to the practical realities of what we can do to decrease the negative aspects of riding.

 The development of the bitless bridle was driven by two distinct aims. Firstly to reduce pain or discomfort in the mouth and decrease symptoms such as head-shaking, and secondly to deal with the negative change of posture commonly associated with bit use. The older solution, and one often recommended in the past when mouth problems caused by bit use were such that a horse became virtually unrideable, was the hackamore.

And while the hackamore certainly gets rid of the bit it still operates on the basis of pain/discomfort by allowing the rider to exert pressure on the ‘chin-groove’ and nose by way of leverage. Once again the rider’s hands dictate how much interference there will be. Given a knowledgeable rider that is aware of the mechanical advantage offered by the leverage and a good degree of sensitivity in terms of how such force might reasonably be applied, plus a level of physical fitness so that the hands are able to act at all times independently of the rider’s torso, the hackamore is not a bad device. But where any of these conditions are missing, or where harsh designs are used, such as those made with sharp curb chains or chunks of bicycle chain (leather covered or not) over the nose, what you actually end up with is something that can do even more damage. So while the hackamore gets rid of pain in the mouth it tends merely to transfer it elsewhere – with equally bad or worse effects on posture and movement.

 So in terms of the second aim, it is essential that the bridle does not cause discomfort in any part of the head and face, chin groove, nose or poll. And unfortunately once complexities are introduced in design, such as where straps cross over or under one another, there tend to be problems with binding or seizing – so that the bridle tightens, applying pressure  to the lower jaw, poll or face, but does not release dependably as soon as the hands give.

 So perhaps it is fair to suggest that these cross under or over types have more to do with the rider’s perception regarding security than with achieving a pain-free medium of communication. Any of those of us that were raised on bitted bridles have absorbed the notion that we must be able to impose our will on the horse by being able to increase mechanical pressure in order to get them to stop. So there is a background feeling of insecurity when we use a bridle that does not allow us to do so. But you just have to watch a bunch of kids riding over jumps in bitless sidepull type bridles and it very soon becomes obvious that the horses are more relaxed and far less likely to refuse to do as asked.

The present trend for using treeless saddles was also a response to the problems of tree’d saddles.

Around the late 1990s the results of scientific research into the effect of conventional saddles on back problems and lameness caused owners and innovative saddlers to begin designing alternatives. Typically the problems they were attempting to solve were to do with the conventional saddles inability to flex through those same 3 dimensions as the vertebra so that, even where saddle fit was good on the standing horse, it simply could not match the changes of shape that occur in the back during movement. And, as discussion of these alternatives grew, it also became increasingly obvious that while some riders had the resources to ensure saddles fitted as well as possible and were made to a high standard many did not.

• 73% of a group of horses showed uneven saddle panels causing significant pressure on the back, with 57% showing back pain and muscle atrophy from saddles with serious multiple fitting problems. (Harman, J.C. (1997) Measurements of the pressures exerted by saddles on the horse’s back using a computerized pressure measuring device. Pferdeheilk. 13, 129-134)

In some cases the problem was that sellers simply didn’t concern themselves overly much with ensuring a good fit.

• Saddles are sold with little consideration of fit and even less knowledge about the consequences of poor fit. (Harman JC (1999). Tack and saddle fit. Vet. Clin. N. Am.: Equine. Pract. 15: 247–261.)

But whatever the reason, research showed that poor fit and unevenness was the source of a great many problems, and established clear trains of cause and effect.

• Poor saddle fit is among the major causes of back pain among horses. (Jeffcott, L.B., et. al., 1999.
Validity of Saddle Pressure Measurements Using Force Sensing Array Technology - Preliminary Studies.
The Veterinary Journal, Vol 158: 113-119.)

It is certainly true that the intention of treeless saddles was to prevent these problems occurring, but any type of saddle used by a rider whose weight is either too great, or is concentrated over too small an area, will cause problems – treeless or not.

• Saddle fit and rider weight distribution are an important aspect of ability to move freely. (Peham et al 2004)

So the claims made by some vendors when treeless saddles came onto the market – that their saddles would work on any shape or type of horse and would cure all kinds of problems – were simply not justified. Although the treeless saddle offers a different set of options, the complexities of the equine back and the interaction between it and rider weight offer a challenge that requires attention to detail and the development of designs suited to specific combinations of horse, rider and activity.

Since NHP began this subject has been an integral part of our journey of discovery, and once we had begun to try a few types out and to develop our own ideas it seemed a natural extension to establish a line of saddles and accessories that would fulfil the ethical imperative that every horse should be able to work in the greatest degree of comfort and safety, and with the least possible impact on natural fluency of movement.

© Andy Beck – W.H.E.E.P. 2006

http://www.equine-behavior.com/

By Jayne Pedigo

There is no such thing as the perfect horse...
However, by being knowledgable about the finer points of equine anatomy and conformation, you can find a horse that is more likely to be able to do what you want him to do, without being compromised by his shape and build.

Below is a drawing showing the main points of equine anatomy and conformation, including some of the things I will be discussing.

Parts of the Horse Art Explosion by Nova

A	Muzzle	B	Poll	C	Crest	D	Withers
E	Back	F	Loins	G	Croup	H	Dock
I	Point of Hock	J	Hock	K	Thigh	L	Stifle
M	Chestnut	N	Ergot	O	Coronet	P	Pastern
Q	Fetlock	R	Cannon	S	Forearm	T	Point of Elbow
U	Shoulder

Let's start at the front end
The first thing people look at in a horse is the head. Although it has little to do with the actual performance of the horse, except for the points noted below. most people like to see a horse with a refined head, bright, kind eyes, pricked ears and an alert expression.

Old English terms such as fiddle-headed refer to horses with coarse, unrefined features, and roman-nosed refers to a horse with a convex profile such as is found in the draught breeds, as opposed to the concave, or dished, profile of the Arabian and similar breeds.

Horses are not capable of breathing through their mouths, so the size and shape of the nostrils are important to horses in highly aerobic activities, such as race-horses. This is the reason that Thoroughbreds tend to have larger nostrils, with finer cartiledge than, say, a draught horse.

The eyes and ears can give clues to the temparament of the horse, if not his athletic ability. Large, kind-looking eyes, with no white showing and no rolling of the eyeballs, indicates a more tractable demeanour, as do ears that are pricked and alert, rather than pinned back against the horse's head.

Two areas of the head which can have an effect on the performance of the horse are the throat and the poll. The poll is where the skull of the horse fits on to the spine, right behind the ears. Stiffness in this area can cause the horse to have difficulty in softening to the rider's hand and "come on the bit". Likewise, a horse with a thick throat area may have difficulty giving to the rider and may give the rider the feel that he is riding a plank of wood.

The horse's neck should be in proportion to the rest of the body, appearing neither too long nor too short. A gentle arch to the neck is pleasing, without excessive muscling underneath. Stallions are more prone to have more crest along the topline of the neck than either geldings or mares, although the more a horse is worked in certain disciplines, such as dressage, the more the muscle along the topline will be toned up. A horse with thick muscling along the underside of his neck will feel stiff and resistant to ride. This can also be changed with exercises to build the muscle along the top of the neck, encouraging the horse to relax the muscles along the underside.

The term ewe-necked refers to a neck that appears to be put on upside down and a horse with a swan-neck has a very long neck, usually with excessive bend similar to a swan, from which the term is taken. Both of these conformations are considered undesirable.

Equine Anatomy - The Shoulder
The way the neck joins the body can influence the way the horse goes. Some horses, such as the Quarter Horse, have a lower set-on neck than do others, such as the Saddlebred. This predisposes the Quarter Horse to carry his head lower than the Saddlebred, such as is desired in Western Pleasure classes and makes him a natural choice for these classes, Many of the carriage breeds, such as the Cleveland Bay, the Friesian and some of the German Warmbloods (who were originally bred as carriage horses and who now excel in sports such as dressage and showjumping) have a much higher neck, giving them a higher head carriage which lends an air of presence.

The shoulder itself is critical to the horse's way of going. A well sloped shoulder (as measured from the point of shoulder to the withers) will allow the horse to take a long, economical stride, enable him to extend in the trot, gallop easily, will make for a more comfortable ride, and is desirable in the riding horses such as the Thoroughbred, the Quarter Horse, and the Hunter. However, it is not found in all riding horses, and the breeds in which a high-stepping, showy action is required, such as the Andalucian, the Saddlebred, and the Morgan will be more apt to have a more upright shoulder, which places the foreleg more underneath the body and results in less extension of the forelimbs, but more upward knee action.

Equine Anatomy - The horse's hoof
You know the saying "No hoof...no horse", well - never a truer word was spoken. The ideal hoof is well-matched with it's partner in size and shape (hind feet will be bigger and the footprint more oval than the front feet) The horn should be strong and flexible, not weak and shelly or dry and crumbly. (I plan on doing some extensive research and bringing you the latest information and help on how to keep your horse's hooves in tip-top condition). Problems with the hoof walls will mean that the horse will have difficulty holding on shoes (a problem I am all too familiar with). Different breeds of horse tend to have different sized feet. The draught breeds have huge soup-plates of feet whereas the Arabians have small strong-horned feet. When trimming and shoeing the horse it is necessary to maintain the natural size of the foot, not to trim it down to fit the shoe, as this will cause problems with soundness, by compromising the natural shock-absorbing qualities of the hoof.

The feet should point straight forward and the horse be neither pigeon-toed, where the toes point in toward each other, nor toed-out , where the horse appears duck-footed with his toes splayed out.

The feet should have fleshy, well-sprung frogs and should not be boxy and upright, like those of a donkey. Lateral ridges around the hoof wall can indicate previous laminitis or, at the very least, changes in growth rate due to illness or changes in feed etc.

                  Dr. Doyle G. Meadows, Professor University of Tennessee

    Conformation of the Tennessee Walking Horse is directly related to skeletal structure. It includes the bones and ligaments which bind the bones together to form joints. The skeletal structure provides the framework that gives the body shape and protects the vital organs. The skeleton of the horse will determine the length and slope of shoulder, overall height and length, length of back and all the other things that are related to skeletal design.
    Generally, the skeletal structures that receive the most attention are the feet and legs. It is obvious that a horse must have structurally correct legs to be a performance athlete or to provide pleasure to its owner. The manner in which a horse moves is determined by the horse's conformation and skeletal structure. The usefulness of Tennessee Walking Horses depends on their ability to move and perform in an appropriate manner.

Front Legs - Front View
The horse's forelimb bears about 65 percent of the weight of the horse. It is, therefore, extremely important to have straight, structurally correct front legs. Due to the amount of weight on the forelimb, there are more front leg injuries as a result of trauma and concussion. It is important to have proper bone length and angle to achieve proper horse conformation (Figure 2).

Figure 2. Front column of bones as viewed from the side. Source: Stashak, Ted S. Adams Lameness in Horses. Fourth Edition. 1987.

As viewed from the front, a straight line from the point of the shoulder should bisect the entire front leg all the way to the toe. There should be two equal parts in the ideally structured horse. Although this is actually rare, the toes and knees should point straight forward. Additionally, the width of the toes on the ground should be the same width as their origin in the chest. The cannon bone should be centered on the knee and fetlock (Figure 3).

Figure 3. Front leg as viewed from the front: A) Ideal, B)Toes-out (splay footed) C) Toes-in (pigeon toed). Source: Heird, J.C. A Guide for Successful Competitive Horse Judging. Colorado State University, Animal Reproduction and Biotechnology Laboratory. Bulletin No. 07. 1992.

There are several deviations to the ideal front column of bones as viewed from the front. Any deviation from the normal has the potential to affect movement and, subsequently, performance. Horses whose toes point inward (toed-in) are referred to as "pigeon-toed" while horses that have toes that point outward (toes-out) are called "splay-footed" (Figure 3). Foot flight patterns are shown in Figure 4.
tennessee walki

Figure 4. Way of Going: (A)Normal foot moves in a straight line, (B)"Base-wide," or "Toed-out" feet move forward in inward arcs, "Winging", (C)"Base Narrow," or "pigeon toed" feet move forward in wide outward arcs, "Padding." Source: Heird, J.C. A Guide for Successful Competitive Horse Judging. Colorado State University, Animal Reproduction and Biotechnology Laboratory. Bulletin No. 07. 1992.

An additional structural deviation in the front leg is base-narrow (Figure 5). This condition is indicative of a horse whose feet stand closer at the ground than at the origin of the legs in the chest. This is typical of horses with larger muscle mass. The base-narrow horse is predisposed to landing on the outside of the hoof wall. Due to the extra weight placed on the outside of the hoof, horses develop conditions such as ringbone, sidebone and heel bruising. Horses with this conformational problem can either toe-in or toe-out.
tennessee walking horse, tennesse

Figure 5. Front leg view: Base narrow. Front leg view: Base wide. Source: Stashak, Ted S. Adams Lameness in Horses. Fourth Edition. 1987.

Base-wide conformation positions the feet of the horse at the ground wider than their origin at the chest (Figure 5). This condition is seen in many narrow-chested horses and is usually accompanied by feet that toe-out. Unlike the base-narrow horse, this condition allows more weight to be distributed to the inside of the horse's hoof. Horses that are base-wide are also predisposed to ringbone and sidebone.
Bowlegs, knock-knees and bench knees are examples of poor conformation that may affect soundness (Figure 6).
tennessee walking horse, tennes

Figure 6. Front leg structural faults: A)Bowlegs, B)Knock-knees, C)Bench knees. Source: Stashak, Ted S. Adams Lameness in Horses. Fourth Edition. 1987

Bowlegged horses present the entire knee in an outward deviation as viewed from the front. This condition causes increased tension on the outside of the leg due to the unequal distribution of concussion and force. Knock-kneed or close-kneed horses have the entire knee set to the inside of a straight line from chest to toe. This condition is generally accompanied by horses being toed-out and with some degree of outward rotation of the cannon and fetlock. Again, this condition is predisposed to unsoundness due to an unequal line of concussion.

Bench knees are another structural fault in horses. Bench or offset knees are characteristic of a horse with the cannon bones set too far to the outside of the knee. This conformational problem increases the possibility for horses to develop splints (Figure 7).
tennessee walking horse, tennessee walking horse,

Figure 7. Splints are bony enlargements in the groove formed by the splint and cannon bone. They may be high or low, forward or back.

Front Legs - Side View
The front column of bones as viewed from the side should have appropriate slope and angle of shoulder and pastern. Additionally, a vertical line should run from the center of the scapula to the front edge of the knee and bisect the hoof as shown in Figure 8.
tennessee walking horse, tennessee walking horse

Figure 8. The front legs, side view: A)Ideal, B)Buck-kneed, C)Calf-kneed. Source: Stashak, Ted S. Adams Lameness in Horses. Fourth Edition. 1987.

Some horses are camped-under in front. This condition refers to a horse whose forelimb is too far under the body (Figure 9). This camped-under effect will prevent a horse from having a long fluid stride and predisposes horses to unsoundnesses. These horses typically have excessive wear on the hoof with an increase in pressure on ligaments and tendons.
tennessee walking horse, tennessee walking horse

Figure 9. Front leg as viewed from the side: A)Camped-under, B)Camped out. Source: Stashak, Ted S. Adams Lameness in Horses. Fourth Edition. 1987.

Camped-out refers to horses whose entire forelimb is too far forward and away from the body (Figure 9). These horses will have excessive concussion and stress on the knees, ankle and hoof. These horses are predisposed to navicular disease and laminitis. Ideal position of the front leg in relationship to the body is shown in Figure 8.

Two primary structural deviations exist in the knees of as horses as they are viewed from the side. The most frequent condition is "over at the knees" or commonly referred to as buck-kneed (Figure 8). This is a forward deviation of the knee set too far forward in the horse's leg. Although a structural deviation from the normal, buck-kneed horses are capable of a long performance life.

The opposite condition to buck-knees is "back at the knees" or calf kneed (Figure 8). This conformation fault is extremely serious and many calf-kneed horses do not stay sound. This condition positions knees that are set behind or back in the horse's leg. Calf-knees allow the knees to bend backwards (hyperextend) and predispose the horse to unsoundness.

tennessee walker

Figure 10. Pastern conformation: A)Ideal, B)Short and steep, C)Long and weak.

Ideal pastern conformation places the angle of the pastern at approximately 45 degrees in front and approximately 50 degrees in the rear pastern, with a moderate length to the pastern (Figure 10). Short, steep pasterns will not allow for the normal "cushion" effect on the forelimb that is found in the ideal. This condition gives a choppy, rough stride that is predisposed to lameness due to extra concussion on the entire front column of bones. Long, weak pasterns allow the horse to injure ankles, tendons and ligaments because the pasterns are too long relative to length of limb.

Rear Legs - Rear View
Ideally, when viewing a horse from the rear for structural correctness, you should draw an imaginary line from the point of the buttocks to the ground which should bisect the gaskin, hock and hoof (Figure 11). This will provide equal distribution of weight, equal bone pressure and equal strain on ligaments. It is not critical that a horse be perfectly straight from the ankles down as viewed from the rear. In fact, most horses naturally stand with the cannons parallel and toe out slightly from the ankles down. This allows a horse's stifle to clear the rib cage in flight, resulting in a longer-strided, freer-moving horse.
tennessee walking horse

Figure 11. Structure of the hind limb as viewed from the rear: A)Ideal, B)Cow-hocked, C)Bow-legged. Source: Heird, J.C. A Guide for Successful Competitive Horse Judging. Colorado State University, Animal Reproduction and Biotechnology Laboratory. Bulletin No. 07. 1992.

Horses that are bowed-in at the hocks, with the cannon bones not parallel, are referred to as "cow-hocked" (Figure 11). Typically, these horses have hocks that are too close, point toward one another and the feet are widely separated. These horses have hind limbs that are base-narrow from the buttocks to the hocks and base-wide from the hocks to the toes. The horse that is "cow-hocked" will have a tendency to be weak in the major movements that require work off the haunches such as stopping, turning and sliding.

Occasionally there are horses that actually toe-in behind and are "out at the hock" (bow-legged). Bow-legged horses (Figure 11) have hocks that are too far apart and are generally predisposed to being base-narrow. These horses have added strain on the bones, ligaments and joints and may have many types of interference in movement. Most of these horses are very poor athletes and should be severely penalized.

Rear Legs - Side View
Conformation excellence of the horse's hind leg structure as viewed from the side is indicated by a line from the point of the buttocks to the ground. Ideally, that line should touch the hocks, run parallel to the cannon and be slightly behind the heel (Figure 12). A horse with too much angle in the hock joint is sickle-hocked. As viewed from the side, the horse is standing under from the hock down, due to the excessive angulation in the hock (Figure 12). Horses with sickle hocks are predisposed to curbs, enlargements below the point of the hock. Many of these horses tend to be outstanding athletes for a brief period of time.
tennessee walking horse, tennessee walker

Figure 12. Structure of the hind limb as viewed from the side: A)Ideal, B)Sickle-hocked, C)Post-legged. Source: Heird, J.C. A Guide for Successful Competitive Horse Judging. Colorado State University, Animal Reproduction and Biotechnology Laboratory. Bulletin No. 07. 1992.

Excessively straight-hocked horses have correspondingly less set (or angle) in the hock joint (Figure 12) and are referred to as post-legged. These horses typically have poor movement, with little flexion, which causes limited drive and impulsion from their hind leg. This predisposes the horse to bog spavins, inflammation or swelling of the soft tissue of the hock, and increases the chance for injury and unsoundness.

Summary
Structural correctness ultimately determines the value and usefulness of a horse. Regardless of whether the horse is a favorite at the Celebration or a youth's pleasure mount, length and angle of the bone structure combined with skeletal correctness play a critical role in the usefulness of the athlete. As the number and severity of structural problems increase, the expected life, activity and performance of the horse are severely limited.

References:Stashak, Ted S. Adams Lameness in Horses. Fourth Edition. 1987.
Heird, J.C. A Guide for Successful Competitive Horse Judging. Colorado State University, Animal Reproduction and Biotechnology Laboratory. 1992.

http://www.legacyspottedwalkers.com/TWH_STRUCTURE.htm

What Makes My Walker Different?

by Rose Miller
(reprinted from August 1993)
© Copyright 1999, Voice of the Tennessee Walking Horse, Lewisburg, Tennessee

Tennessee walking horses do possess one rather unique difference from most other horses. Stated simply. . . they have longer hind limbs than most horses that trot. I say "most" because we will see that some trotters have long hind limbs, some to their disadvantage, and some to their advantage, but not with the regularity of the walking horse. First, let's look at the three different types of hind limbs found on horses.

Type 1 is considered to be the best for most uses. When the horse is posed with his hind cannon vertical, a line dropped from his buttock to the ground should graze his hock and the hind cannon bone.

Type 2 has the vertical line dropped behind the vertical cannon bone. This type is found in draft horses.

Type 3 has the vertical line falling within or in front of the cannon bone.

This is found in pacers and gaited horses and is an important point for "all breed" judges to keep in mind, as horses with Type 3 hind limbs will stand either "camped out" or sickle hocked. The horse with sickle hocks is also predisposed to unsoundness, unless the hock is well formed and strongly supported with proper muscles and ligaments. Fortunately, most walkers seem to have inherited strong hocks, but too much of a sickle hock is not desirable.

There are several ways to have a long hind limb, and there are variables on the length of limb. This should be taken into consideration when breeding or buying a horse. With proper "walking conformation" the horse should gait, but do you need a long-striding show horse or a more compact using-horse? Let's see how these differences might work.

Basically the shorter, and therefore straighter the hind limb, the more easily it can deliver the thrust of the hind muscles downward to the ground.

The horse with the longer, crooked or Z shaped limbs, can more easily bring his hocks forward and track up, or overstride.

A walker with less length to his hind legs or less angulation will have less overstride; but he will perhaps be more functional as a horse used in ranch work, jumping, or speed and action events. The walker with the longer, more angulated hind legs can excel in the show ring or on park trails. This difference is seen in trotting breeds as well. The dressage athletes have longer hind limbs so they can extend at the trot, and an overstride at the walk is of value.

The jumpers, however, have shorter hind limbs so they can dig in, thrust, and jump. If you watched the Olympics, you likely noticed that the three day event horses did not perform the dressage patterns as smoothly or as excitingly as did the dressage horses. This is because the dressage stars have conformation conducive to forward stride and fluid movements, not the power necessary for three day eventing.

Now let's look at hind limb construction (as shown in Figure #1) from the hip down to the foot, and see how it works. The horse's pelvic length is measured from the hip joint to the point of the buttock. The larger the pelvis is, the larger can be the propulsive musculature and the more power the horse can produce. An old rule of thumb in conformation judging is that you should be able to divide the horse into thirds. The front one-third is from the point of the shoulder back to the elbow and withers; the back from the withers to the point of the hip another one-third, and from the point of hip to point of buttock is the other one-third. A horse with less than one-third of his body length in the pelvic area won't have the power to push the longer lower hind limbs under the horse as far or as easily as one with greater length and musculature. We also need to look at the pelvic slope. It should be moderately sloped, not tending toward flat, or the horse will "leave his hocks behind" as he travels, again not allowing our walker to stride up under himself.

The next area to look at is the femur, or thighbone. This is an extremely important link in the hind leg assembly. Think of the hind leg as a series of rod like links. First the femur, then the gaskin bone, then the cannon bone and pasterns. If these bones were hanging by themselves and set swinging, they would behave like a chain pendulum in which whatever the uppermost governing link does the rest of the links follow in the same manner.

A long first link, or femur would therefore set the leg in the slower, longer swing. This is part of what can give the walking horse the long slow ground covering stride that we all appreciate. This does not mean that a walking horse with lesser length of the femur won't gait, but it will be a shorter more rapid stride suitable for rougher riding or ranch work. Shorter femurs are desirable in trotting horses that are used in speed events or sprint racing. In a sprinter, long hind limbs prevent the thrust generated by the rump muscles from being delivered to the ground and is a disadvantage. Having a longer femur gives the walking horse longer hamstring muscles which should tie in low to the Achilles tendon. In a profile view of the rear legs, the hamstring muscles should flow down, making that part of the leg appear long. If it appears rounded and the notch in the profile from buttocks to hocks is deeply indented, he ties on high, the femur is short and so is the hamstring muscle. This will limit the forward movement of the hind leg.

The next link on the chain is the gaskin bone and muscle. The pelvic and femur length is often hard to see because of the muscles of the rear quarters, but the gaskin length is easy to see. This is the bone from the stifle to the hock. Most walkers have longer gaskins. However, we need to remember that if the femur isn't also long, the swinging leg pendulum won't produce the long slow stride we desire. If rightly proportioned, the longer gaskin and the long femur are desirable in our walkers. A long gaskin in most trotters is a disadvantage, some exceptions being horses used for dressage requiring extension of rear legs and saddlebreds. Walkers being used as trail horses in rough terrain or working ranch horses won't find a very long gaskin of benefit. These horses will do better having a gaskin and femur more near equal in length. Ideally, in the trotting pleasure horse, the femur is longer than the gaskin in length.

Next is the cannon bone. This bone should be short, so the horse's hocks are close to the ground. High hocks predispose the horse to "travel downhill" especially if they are quite a bit higher than his knees and he will have trouble getting his hocks up under himself, a very important thing to remember with our running walk. A good way to judge the length of cannon bone length is to compare it with the front cannon length. The hock should appear only a little higher than the knee. In the front leg, the upper arm should be longer than the cannon. It is considered good conformation to have low hocks in any riding horse.

In a visit to a standardbred training facility, I noticed that the pacers had gaskins longer or equal in length to long femurs; but in all the ones I saw, the hocks were set high, with relatively long cannon bones. It makes sense when you remember that for racing the pacers need a fast swinging of the hind legs, easier when the leg below the femur is more equally divided in length. This is not the long slow sweeping stride we desire in the walking horse.

In review of the Tennessee walker's long hind limb conformation, we see that the most correct way is to have one third of the horse's body length in pelvic length for power with a moderate slope, a long femur with it's accompanying long thigh and hamstring muscles to provide the long slow swing of his leg pendulum, a moderately long gaskin to give more overreach and short cannon bones enabling him to set his hocks under himself.

The front half of a walking horse has the same problems, faults and good points as our trotting friends. Here again, the use we have planned for our horses makes a difference in what we look for in conformation.

A horse has two bones in his shoulder, as shown in Figure #2. The scapula runs from the point of the withers to point of the shoulders. The humerus or arm bone goes from the point of the shoulders to point of the elbow. How these bones relate to each other determines how a horse moves in front. In talking about how a walker "moves out of the shoulder" we are most familiar with the scapula, or shoulder blade.

However, the humerus is very important and seldom talked about. It is capable of side to side movement, and also swings from back to front, raising or lowering the elbow. It determines the way a horse will fold or unfold the elbow, knee and fetlock joints. It determines the style or way of going of the front end of the horse.
The longer the humerus the more scope the horse will have. Scope is defined as the ability to move the elbow away from the body, either toward the front or to the side. Scope is a very desirable characteristic. To be considered long, the humerus must be at least 50% of the length of the scaupla. Better motion is seen with the length closer to 75%. The shorter the humerus, the more short gaited the horse will be, moving with short, stiff, choppy strides. In our walkers we must have this length to allow the forearm to extend forward. No matter what the length or angle of the shoulder, without a long humerus the horse can't roll out of the shoulders.

The steeper the resting angle of the humerus, the higher the horse can raise his knees. This is of obvious importance to those of us who want to show our horses. The most spectacular natural action is shown by horses with a moderately upright shoulder, around 55 degrees, and a long steep humerus. Hackneys and park horses are good examples. Since we like our walkers to have reach forward as well as natural upward action, the walker's shoulders should be more sloping, between a 45 and 50 degree angle. A very sloping angle of around 45 degrees is found in racing thoroughbreds and dressage stars who need great forward extension, but little knee action. A long upright humerus with a moderately sloping shoulder is what we need if we want natural elevation with as little fuss as possible.

A horse with a more horizontal humerus will have less natural ability for high action or tight folding. He will move with little elevation of his front legs and will have difficulty in raising his forearms to level and may hang his knees.

In order to have a rolling shoulder, the angle between the scapula and the humerus must be at least 90 degrees. Less shortens the forward movement of the whole shoulder. A shoulder slope of 45 degrees needs a humerus angle of 45 degrees to keep a 90 degree angle between. A shoulder angle of 50 degrees needs a 40 degree angle of the humerus.

Many walkers seem to fall into the category of medium angle of the humerus. They may not make high stepping show horses; but their movement will be pleasant. They would probably show well in western, trail pleasure and lite shod classes and be wonderful riding horses. Their shoulder angles are probably between 51 to 55 degrees with a humerus angle of between 39 to 35 degrees. Heavy shoes and other training methods will have less of an elevating effect on these horses.

The humerus with a low angle of 30 degrees or less has several disadvantages. If the angle between humerus and scapula are to be kept at 90 degrees, the shoulder will have to be quite steep, closer to 60 degrees. The shoulder will be long in order to join with the low humerus and this will push the elbow back too far. This results in the horse being "pigeon breasted" with two much of the horses sternum being visible in a side view. This makes the horse heavy in front and he definitely will have trouble going in a balanced way. He will feel like he is traveling downhill, and no training method will be able to get him to pick up his front feet like a show horse. A horse with this conformation will have a humerus angle of around 30 degrees or less. If the shoulder is less than 60 degrees or more sloping, he is in even more trouble because his shoulder isn't open 90 degrees and his range of movement is further constricted.

By looking at the resting angle of the humerus, you can get an excellent idea of how the horse will carry his head. Low humerus, low head, high humerus, high head. By studying the angle of the shoulder or scapula, you can get an idea of how much the horse will extend his front legs. A line drawn from the point of withers through the point of shoulders and on to the ground will show the farthest a horse can extend. This is seen easily in a trotting horse at the extended trot and in a galloping stride. In a walking horse it is harder to see since he uses a more up-and-down front leg movement, but it works the same way - a steeper shoulder, the less forward movement, a more sloped shoulder the more extension.

We see that there are many variations of the shoulder construction, and the resulting movement of the horse. In order to have a very good horse, both the front and the back of the horse need to work in a balanced manner. A horse can stride in front only as far as his hindquarters are capable of pushing him, but a short reach in front will limit a powerful thrust from behind.

By applying these principles of conformation, you can choose the horse you want for the purpose you have and avoid the horse with conformation likely to be unsound and cause him to travel in an unbalanced manner.

http://www.twhbea.com/Voice/Features/walkerDifferent.htm

Upward Pateller Fixation

Reprinted from: The Atlanta Equine Clinic

Intermittent upward patellar fixation is a condition whereby the horse�s pelvic limb temporarily "locks" in extension. As a result, there is a delay in flexion of the limb. The delay in flexion can range from milli-seconds to over several minutes. A short delay in flexion may manifest only as a subtle pelvic limb asymmetry or lameness; severely affected horses (with a long delay in flexion) may be unable to flex the affected limb without assistance.

What is the "Patella"? The horse�s stifle joint is analogous to the human knee. Just like humans, horses have a patella, or "knee cap", which slides along the distal aspect of the femur (thigh bone) during flexion of the joint. The patella slides within a groove (called the trochlear groove) and serves as a fulcrum for the extensor muscles and their tendons as they course over the front of the stifle (or knee) joint. The patella is attached proximally to the quadriceps and biceps femoris muscles and distally to the tibia. In humans, the patella is attached to the tibia by one distal patellar ligament. Horses have 3 distal patellar ligaments: the medial patellar ligament, the middle patellar ligament, and the lateral patellar ligament.

How does the horse �lock� the pelvic limb? Horses have the ability to lock (or fixate) the pelvic limb in extension. This is possible due to the unique anatomy associated with the horse�s stifle joint. The proximal aspect of the medial femoral trochlea is shaped similar to a hook or ski jump. By placing the space between the medial and middle patellar ligaments over this hook, horses can "lock" their pelvic limbs in extension. Once locked, minimal effort is required to maintain limb extension. A similar locking apparatus in the thoracic limbs allows horses to sleep while standing. Therefore, patellar fixation while standing is a normal process in the horse.

What is �intermittent upward patellar fixation�? Although patellar fixation is normal in the standing horse, it can produce pelvic limb dysfunction if it occurs during exercise. Inadvertent locking of the patella over the medial femoral trochlea prevents normal flexion of the affected limb(s). Consequently, pelvic limb asymmetry and lameness frequently become evident.

What causes upward patellar fixation? There are 3 primary causes of upward patellar fixation in the horse:

• Lack of fitness: Lack of quadriceps and/or biceps femoris muscle tone results in an inability to quickly pull the patella up and off of the medial femoral trochlea.
  
  
• Straight or upright pelvic limb conformation: This places the medial femoral trochlea further distad in closer proximity with the patella, facilitating patellar fixation.
  
  
• Excessive distal patellar ligament length: This places the patella proximad in closer proximity with the medial femoral trochlea, where it can inadvertently "catch" or "lock"

It should be noted that the factors which cause upward patellar fixation are often interrelated. For example, an unfit horse will generally have increased laxity (and therefore increased length) of the distal patellar ligaments. Furthermore, if unfitness is secondary to another disease process (such as neurologic disease), intermittent upward fixation may also occur secondarily. Therefore, it is important to assess the horse as a whole prior to determining the cause for upward patellar fixation.

What are the clinical signs? Horses with intermittent upward patellar fixation will exhibit clinical signs during their attempt to flex the pelvic limb from an extended position. In acute severe cases, the pelvic limb may stay locked in extension. The horse may not be able to flex the stifle and tarsus without assistance. In some instances, the condition may temporarily resolve only to recur after taking a few steps. These signs are quite obvious and diagnosis is relatively simple if the condition is severe. Most of the time, however, there is only a "catching" of the patella as it slides up and over the hook and the limb does not truly lock in extension. In this situation, there may only be a mild pelvic limb asymmetry or lameness. This type of lameness can be easily confused with other problems and therefore may present a dilemma in regard to accurate diagnosis. Following are common clinical signs associated with mild to moderate forms of intermittent upward patellar fixation:

• Non-weightbearing pelvic limb lameness
  • This may be distinguished from tarsal (hock) soreness which is usually weightbearing in nature
  • The horse will frequently drag the toe of the affected limb(s) during exercise
    • Visible wearing of the dorsal aspect of the toe/shoe may be apparent.
  • The foot of the affected limb(s) will have a low-arc flight pattern
  • The horse will usually exhibit a shortened cranial phase to the stride
• Resistance in the canter
  • The horse will resist the canter, particularly if circled toward the more affected limb
  • Resistance may be most noticeable during the transition between the trot and canter, when the horse is forced to extend the pelvic limb for a prolonged period
  • Many horses will toss their head, rear, or stop when asked to canter. This may be due to their "anticipation" of impending upward patellar fixation.
  • The horse would rather trot than canter (which is harder for the normal horse)
• Consistent lead changes or cantering on the wrong lead
  • The horse avoids prolonged pelvic limb extension with the affected limb. This is particularly apparent when cantering in a circle towards the affected limb.
• The canter is very rough or "bouncy"
  • This occurs as a result of consistent delay in pelvic limb flexion from the extended position
• Swelling, heat, and/or pain may be associated with one or both stifle joints
  • Upward patellar fixation causes patellar instability which in turn may result in femoropatellar synovitis
• The horse drags his hind toes during exercise
• Resistance and/or difficulty when walking up and down hills, or when backing up
  • These situations force the horse to extend the pelvic limb for a prolonged period
  • Rather then fully extend the pelvic limb(s), the horse may "crouch" while walking
  • Rather than flex the pelvic limb(s) normally, horses will often swing their limbs to the outside
  • This may cause the lameness to be confused with neurologic disease (such as EPM or stringhalt)
• Lameness is most severe when the horse is first taken out of the stall
  • Many horses will improve as the workout progresses
• Lameness becomes more obvious following an extended period of stall rest
  • Loss of muscle and patellar ligament tone exacerbate the upward patellar fixation
  • The horse does not improve (and may worsen) as a result of taking time off
• The horse does not respond to anti-inflammatory (e.g. Phenylbutazone) therapy
  • Intermittent upward patellar fixation is a mechanical problem and is not inflammatory-mediated

As with many cases of pelvic limb lameness, secondary abnormalities such as thoracolumbar ebaxial (back) and proximal thoracic suspensory ligament soreness are also present. These are generally detected during the passive lameness evaluation and are suggestive of chronic pelvic limb asymmetry/ lameness.

How is upward patellar fixation diagnosed? Clinical signs are characteristic and, if the limb is locked in extension (i.e. the case is severe), diagnosis is simple. As previously mentioned, however, most cases are mild and diagnosis may be more difficult. A detailed history and careful clinical evaluation are essential parts of a proper workup. One helpful diagnostic aid involves placing the horse in one or more situations where prolonged pelvic limb extension is normally required. Such situations include walking up and down hills, the trot-to-canter transition, and backing up. When confronted with these situations, the affected horse will either 1) demonstrate upward patellar fixation by temporarily locking the pelvic limb, or 2) cheat by switching leads, swinging the limbs to the outside, avoiding pelvic limb extension, etc.

Many times, a slight hitch or "catch" is visible as the pelvic limb begins to flex from an extended position. This "catch" is most easily detected by visualizing the point of the hock as the horse picks the limb up to advance it cranially. Infrequently, an audible "snap" or popping sound is also evident during exercise (particularly walking).

In many instances, upward patellar fixation can be produced in affected horses by manually forcing the patella upward and outward. The examiner may actually be able to keep the pelvic limb locked in extension using minimal effort.

Since the problem is usually secondary to conformation and/or level of fitness, it is almost always bilateral. However, affected horses historically exhibit clinical signs in one pelvic limb. It is not until the more affected limb is successfully treated that a problem in the contralateral limb is manifested.

How is upward patellar fixation treated? Currently, there are 5 forms of treatment for intermittent upward patellar fixation:

• Exercise: Lack of fitness results in decreased thigh muscle and patellar ligament tone. With decreased supporting muscle and ligament tone, it becomes easier for the patella to lock on the femur and harder for it to replace within the trochlear groove. In subtle cases of upward patellar fixation where conformation is relatively good, increased exercise alone may result in resolution of the problem.
  We frequently ask the client to grade the level of their horse�s current level of fitness on a scale of 1 to 10 (1=very unfit; 10=extremely fit). We suggest achieving a fitness level of at least 7-8 (if possible) prior to pursuing other forms of treatment. This will rule out unfitness as a major contributor to the problem as well as increase the effect of other therapy.
  
  
• Corrective Shoeing: Since fixation of the patella occurs when the pelvic limb is extended, prolonging the extension phase of the stride can make "unlocking" more difficult. Alternatively, shortening the amount of time the pelvic limb spends in extension allows the horse to unlock his/her patella before the distal patellar ligaments become excessively tight. Since the conformation of the distal pelvic limb and/or the toe length is intimately related to pelvic limb breakover, the farrier can frequently alleviate the problem via corrective trimming/shoeing. Rolling and/or rockering the toe of the shoe, applying a full (egg-) bar shoe, and/or the use of wedged pads (when needed) are commonly used techniques. In many cases, we are able to help the pelvic limbs break over before intermittent upward patellar fixation occurs.
  
  
• Hormonal Therapy: The administration of estrogen has shown to prove benefical for some horses exhibiting intermittent upward patellar fixation. The presence of estrogen within the body of the horse may increase tension of various supporting ligaments. These include the collateral, suspensory, cruciate, and distal patellar ligaments. Increasing distal patellar ligament tension helps to relocate the patellar further distad, thereby making upward patellar fixation more difficult. This in turn may alleviate clinical signs.
• It should be noted that estrogen is also a powerful behavior modificator in the horse. It is often used for stallions and geldings that are excessively difficult to handle, aggressive towards people or other horses, or overly anxious at shows and other events. Estrogen is very effective at reducing anxiety and resistance as well as improving overall behavior in these horses. Treatment usually consists of 2 injections of estrogen (25mg) in the muscle twice weekly for 4 consecutive weeks, then as needed therafter.
  
  Administration of estrogen to mares usually causes them to exhibit clinical signs of estrus (heat). Since this change in behavior is generally undesirable, we do not recommend its use in mares.
  
  
• Intraligamentous Infusion of Counterirritant: This form of therapy is usually referred to as "blistering". Blistering involves the inject of an irritative substance into soft tissue(s) in an attempt to create an inflammatory reaction. The irritative substance usually consists of iodine 2% in an almond oil base. This substance can elicit an inflammatory response for up to 30 days depending on the amount used and the location of injection. It is important to remember that fibrosis and scar tissue formation within normal soft tissues will occur as a result of severe inflammation. As you know, scar tissue does not function like normal soft tissue. Therefore, blistering in certain areas may inhibit proper function of associated soft tissue. It is for this reason that The Atlanta Equine Clinic typically does not institute blistering as typical form of treatment for soft tissue problems.
  
  However, in the case of intermittent upward patellar fixation, we gain a biomechanical advantage by replacing normal tissue with scar tissue. The infusion of counterirritant within and around the medial and middle patellar ligaments results in the elicitation of an intense inflammatory reaction by the horse�s body. With inflammation, fibrosis and scarring of the patellar ligaments occur. During the scarring process, soft tissues will contract (shorten). As the patellar ligaments shorten, the patella is pulled up and over the hook of the medial femoral trochlea and into its normal position within the trochlear groove. At this point, it becomes more difficult for the horse to lock the patella and easier to flex the pelvic limb from an extended position. In our hands, this from of treatment has been extremely effective in a vast majority of cases involving intermittent upward patellar fixation.
  
  
• Medial Patellar Desmotomy: The medial patella ligament is one of the key structures (along with the patella and middle patellar ligament) that is required to lock the patella on the femur. Since the problem represents the horse�s inability to quickly disengage the patella from the medial femoral trochlea, surgical resection of the medial patellar ligament results in complete resolution of the problem. Once the medial patellar ligament is resected, upward patellar fixation becomes impossible and the clinical signs associated with this condition disappear. Consequently, this has become a very popular form of treatment for horses with intermittent upward patellar fixation.
  It is extremely important to note, however, that the medial patellar ligament also performs another function: stabilization of the patella within the trochlear groove of the femur. Without tension from the medial patellar ligament, the patella becomes unstable within the femoropatellar joint. Femoropatellar synovitis and frequently osteoarthritis result. Since the stifle is high-motion in nature, chronic inflammation within this joint poses a significant concern in regard to future performance soundness. Persistent femoropatellar joint inflammation typically needs to be addressed on a continual basis and often requires considerable maintenance therapy. It is for this reason that The Atlanta Equine Clinic views this form of treatment inappropriate except for the most severe of cases that have proven refractory to the other forms of therapy.
  
  
  http://www.eastwindwalkers.com/horseinformation/stiflepage2.html

Agdex#:	460/660
Publication Date:	07/76
Order#:	76-071
Last Reviewed:	08/97
History:	The Material in this Factsheet was originally prepared by Robert C. McClure, Gerald R. Kirk and Phillip D. Garrett, Department of Veterinary Anatomy, School of Veterinary Medicine, for publication in Science and Technology Guide, University of Missouri - Columbia Extension Division.
Written by:	Robert C. McClure; Gerald R. Kirk; Phillip D. Garrett;

Table of Contents

1. Overview of joints and diseases
2. Bone Spavin
3. Bog Spavin
4. Ring Bone

Overview of Joints and Diseases

The junction between any two bones is known as an articulation or a joint. There are several types of joints. Some are fixed or practically immovable, such as those found between the skull bones. Others are freely movable and have articular cartilage and joint capsules.

The articular cartilage covers the ends of the bones and reduces friction between bones. The joint capsule surrounds the joint and consists of a tough, outer coat and a thin inner layer which lines it. This inner layer is termed the synovial layer and it produces a fluid known as the synovial fluid. This fluid resembles egg white in consistency and lubricates the joint when the bones move against one another.

Parts of the outer layer of some joint capsules are thickened to form ligaments. Ligaments connect bone to bone while tendons connect muscle to bone (Figure 1).

Arthritis is an inflammation of a joint involving the bones, the articular cartilages, ligaments and joint capsules. In an infected or irritated joint the amount of fluid increases and produces swelling. Bacteria may enter the joint through a wound of the joint capsule resulting in damage to the bones and cartilages. The joint may then become immovable. To treat this condition the affected joint is rested. Medication is used to counteract the inflammation. If the arthritis is severe, immobilization and resting of the joint is continued for 4 to 6 weeks. The outcome is usual favorable if bone damage or new bone growth has not occurred.

An injury to a ligament is defined as a sprain. Some ligaments hold bones firmly together and allow very little movement; others allow considerable movement. If an abnormal stress or movement is placed upon a joint such as overextension of a joint, the ligament may be torn. The amount of injury depends upon how much force is placed upon the ligament. If the ligament is torn completely away from its attachments to a bone, recovery is difficult. Adequate rest is necessary in hope that the torn ligament may repair itself.

Joint mice are pieces of bone or cartilage found within the joint cavity and may be the result of a fracture. These produce pain when lodged between the articular surfaces and may also produce arthritis. Surgical removal is usually successful (Figure 2).

A "stifled" horse results from the "locking" of the patella (knee cap of man) in the stifle joint. Normally a horse stands for hours without tiring of the hindlimb musculature. This is due to the "locking" mechanism of the hindlimb. The "locking mechanism" consists of the loop formed by the junction of two patellar ligaments with the patella and the bony projection of the lower end of the femur (thigh bone).

The stifle joint is locked in an extended or straightened stiff position whenever the horse is unable to "unlock" the loop of ligaments from over the bony projection. Sometimes a slap on the croup will cause the horse to jump and "unlock" the stifle joint. Often his "locking" will reoccur. Whenever surgery is necessary to correct the condition, the medial patellar ligament is cut on the inside of the stifle joint in order to prevent further "locking" (Figure 3).

Bone Spavin

Bone spavin is defined as an inflammation of one or more bones of the hock andmost often causes an arthritic condition of the affected bones. In bone spavin the joint between the bones on the inside of the hock become immovable. Quick stops,such as those which occur during roping and other stresses, along with mineral deficiencies, may produce bone spavin. Horses with full, well-developed hocks tend to have less incidence of bone spavin than those with narrow, thin hocks. Bone spavin occurs on the inside of the hock (jack spavin). It may occur between the bones within the hock joint and cannot be seen or palpated (blind spavin). A large percentage of horses affected with blind spavin recover completely.

Jack spavin is usually a bony growth of variable size.The bony enlargement pushes out against a tendon that lies over the inside hock area (Figure 4).The cause of bony growth cannot be fully explained. When the hock is flexed or bent, pain is produced and as a result the hindlimb is not raised very high. Therefore, the horse drags his foot (Figure 5).

Treatment consists of alleviating as much pain as possible. By cutting the tendon veterinarians can remove one source of pain. However, the outlook for full recovery from jack spavin is usually not favorable even with surgery. The horse will probably be useable, but rest and time are needed for repair to occur.

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Bog Spavin

There is no bony enlargement; swelling, heat and pain are most evident on the front surface of the hock (Figure 6).

The cause may be due to nutritional deficiencies, accidental injury to the hock joint or the hocks being too straight (hereditary). If the condition is caused by conformation or too straight hocks, it cannot be treated successfully. Veterinarians have many factors to consider in order to determine the cause and to advise the best treatment. Anti-inflammatory drugs may help bog spavin caused by nutritional deficiencies or injury. The drugs decrease inflammation and prevent swelling of the joint capsule. A bandage around the hock prevents excessive build-up of fluid and swelling. The horse is rested for 4 to 6 weeks. Adding vitamins and minerals to the diet may relieve bog spavin. Horses 6 months to 2 years of age are most often affected with bog spavin.

Ring Bone

This condition is characterized by new bone growth which occurs on the first, second or third phalanx (high or low ringbone). The phalanges are the three small bones extending from the fetlock to the hoof (Figure 7).Ringbone is more common on the forefeet than the hindfeet.

Ringbone is due to an inflammation of the tough fibrous layer which surrounds the bones. The inflammation may be caused by stresses which pull on ligaments attached to the bone. The new bone growth may lead to arthritis and stiffening of the joints between the fetlock and the pastern. If the tough, fibrous layer surrounding the bones is cut (such as in wire cuts), new bone growth may result. The new bone may grow into the joints between the phalanges and produce stiffening of the joints. In early ringbone, swelling and heat are present over the affected areas. To assure a complete diagnosis, it is necessary to take radiographs. Again the veterinarian has many factors to consider in advising the best treatment. If the joints are involved, chances for full recovery are poor. Immobilization of the foot and a long period of rest are often necessary. Corrective shoeing is also advisable in some cases.

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The Natural Pace of Work Why Don't Grazing Horses Gallop? In Idle Theory's view, living creatures attempt to minimize the duration of work. If so, why don't they perform this work as rapidly as possible? Why don't they run around when busy? And for that matter, why don't busy people, out shopping or commuting, also run around? After all, if they ran, they'd get work done quicker, wouldn't they? The answer is that such a view does not take energy into account. Anyone who runs from place to place, from A to B, accelerates their body mass from standstill to running speed in some short interval of time. And in order to come to a halt again, they must deccelerate their body mass from full speed to standstill. Since this acceleration up to full speed requires work to be done, with more work with greater acceleration and higher top speed, it follows that the more rapidly some animal moves from A to B, the higher its energy expenditure in accelerating, deccelerating, and overcoming resistance to motion (friction) while travelling at full speed. In the case of a grazing animal, which moved from tuft to tuft of grass, with each tuft having some small energy content, the expenditure of energy in sprinting from tuft A to tuft B may exceed the gain in energy from consuming a tuft of grass. Running from one tuft of grass to another, a grazing animal may actually lose energy. But equally, if a grazing animal moves at a snail's pace from one tuft of grass to another, barely accelerating and deccelerating at all, it may spend so long in going from A to B that it will expend more energy with its basal metabolic rate (breathing, maintaining blood circulation, etc) over the long period it takes to move from A to B than it gains once it has reached B, and eaten another tuft of grass. If so, and there is a net loss of energy from moving from A to B too rapidly, or too slowly, then there is most likely a happy mean where it moves from A to B at some optimum speed that maximizes net energy gain. And this optimum might be called the natural speed of motion, or the natural pace of work - where the 'pace of work' translates as power output. Other factors may also need to be taken into account. The legs of animals may be regarded as pendulums with a natural swing period, and swinging their legs faster or slower than this natural swing period will entail performing more work, either in accelerating their legs or braking them. The natural speed of motion of an animal may simply be defined by the length of its legs. However animals don't have fixed length legs, and when animals run, they raise their legs, and thereby shorten them, and shorten the swing period. So animals with variable length legs may have a variety of natural harmonious speeds. Also, since muscular activity releases combustion products, these require to be exhausted before further work is done. In an internal combustion engine, the engine performs work when the fuel-air mix in a cylinder explodes and drives a piston. For the remainder of the cycle, the piston returns to its former position, forcing exhaust gases out of the cylinder. So an internal combustion engine isn't actually continually performing work, but only doing so about half the time it operates. It alternates between work and relaxation. A semblance of continuous work is achieved by using several cylinders in line, such that one or more are working while the others are 'relaxing'. The longer any effort is sustained, the lower the work rate. Long distance runners don't sprint all the way: that way brings exhaustion. In general it would seem that the longer the duration of any activity, the greater the need for periods of relaxation. A sprinter's efforts are concentrated into a few seconds. Football games last 90 minutes, with a 15 minute half time. And while footballers periodically sprint, they spend the remainder of the time walking slowly or standing still. A game of cricket may last an entire day, but batsmen only swing momentarily at a ball, and fielders only intermittently run to stop flying balls. A game of golf may last for several days, but entails moving at walking pace, and periodically striking a ball. If there is a natural pace at which any work should be performed, it will necessarily be a relatively leisurely pace, rather than with the mightiest exertion. If this natural pace is exceeded, or retarded, net work done per unit time falls. The same applies to mental work as physical work. After all, a brain is simply another organ that performs some kind of work, and requires energy to power it, just as computers need an electricity supply. One can no more mentally work continuously than one can physically work continuously. And the greater the mental exertion required, the longer the periods of compensatory relaxation needed. It is necessary for office workers, whose work is essentially mental in nature, to have coffee breaks, cigarette breaks, lunch breaks, and to just gaze out of the window for a while now and again. If this is not permitted, exhaustion will follow, and less work will get done overall. If hard-working executives in high pressure jobs suffer 'burn-out', it is because they have been either been overworking themselves, or have been overworked.

Author: Chris Davis
First created: 29 March 2006

Use - types of horses | Where to find horses of riding type | Posture vs. structure | Straightness | Roundness and collection | Rate of skeletal maturity | Links to images | Additional references | About the Author

Take-home message

• Conformation is the study of body proportions. Body proportions depend primarily upon the underlying skeletal structure. However, many "apparent" conformational features are actually produced by posture (the way the animal carries itself) rather than structure. It is important to differentiate the two.
   
• Judgements as to what is "good" in conformation depend upon the work or use that the horse is intended to do. There is no one "good" shoulder, pastern, or pelvic structure.
   
• Determining what is "good" conformation also depends upon an understanding of basic biomechanics, or how the body works. Understanding the rate of skeletal maturation is also important. There is much published misinformation in these areas.
   
• Horses today may usefully be classified into five general types: riding horse, flat-racer, carriage and harness horse, draft horse, and "projects."
   
• A well-conformed riding horse does not look like a well-conformed flat racer. Thus, in order to train the horse intelligently or to ride it well, it is first necessary to know the use-type to which your horse belongs. To a great degree, this will be determined by his parents and grandparents. Structure cannot be altered, but the way the animal uses himself can be modified through training.

Use - Types of Horses

Horses today may be usefully classified into five general "use types": riding horse, flat-racer, carriage and harness horse, draft horse, and "projects." The following is a summary of the three most common types and their most important conformational points. (Please refer to images 1 through 7 for explanation of terms.)

Riding Horses: The job of the riding horse is to carry weight over a distance of ground. The riding horse must go from "point A" to "point B" over and over again over a long span of years, while remaining sound.

Loins: broad from side to side, deep from loin to groin, short from hips to ribs. The ideal is to have a smooth, strong coupling. This (and not the height of the horse) is the most significant determinant of its ability to carry weight

Overall body balance: level to slightly uphill.

Neck: shaped to arch readily.

Head: must be symmetrical, not too bent or too short or fine in the muzzle.

Pelvis: 18 to 22 degrees of slope is ideal. Very shallow or very steep pelvic angles are problematic. Moderate length is sufficient.

Limbs and feet: Ideal is 8" of "bone" per 1,000 lbs. weight. The broadest possible hock, and correctly aligned hindlimbs, are a real plus.

Race Horses: The job of the flat racer is to go as fast as possible over a relatively short distance. Flat racers go from "point A" to "point B" in the shortest possible time, and in many cases need do this only one or a few times. Their careers terminate when their soundness sufficiently disintegrates.

Loins: narrow from side to side; moderately deep from loin to groin; long from ribs to pelvis. The ideal is for a smooth topline through this region, but in many cases it is not. The emphasis here is on flexibility, for coiling/uncoiling the loins is the most significant determinant of stride length and hence the ability to cover ground.

Overall body balance: downhill to the front. The shorter the distance over which the animal is to be raced, the more downhill the build must be. Sprinters are built more downhill than milers.

Neck: Thin and straight.

Head: Symmetry is good but its lack can to some extent be compensated for; head must not be too large.

Pelvis: 18 to 22 degrees of slope is ideal. Shallower angles can, however, be tolerated and may add to speed. Steep pelvic angles are undesirable. The greatest possible pelvic length is desirable.

Limbs and Feet: 7" of "bone" per 1,000 lbs. of weight is sufficient. Amounts over 8" are undesirable. Bones composing the forelimbs must have absolutely correct alignment.

Projects: We can laugh about this category a little bit together, for most of us own "projects" of one type or another. I cite two common types of "project":
1. The rescue case, and
2. The horse being used out of his type.

All "projects" are desirable insofar as they tend to foster the development of horsemanship. However, the owner must not expect the "project" to succeed as fast or perhaps ultimately not as well as the animal that has had the best of care and which is used within its type.

We can all appreciate the horsemanship that goes into some of the more "obvious" instances of use-out-of-type. For example, let us say that a man buys a small-sized Belgian mare, and then decides that he wants to train her for exhibition as a Reining horse. There is nothing wrong with this at all, the horse will be able to do it, the man will learn a lot by trying it, and if he does a good job, the animal will not only remain sound but will put on some mighty entertaining exhibitions of reining maneuvers done in its own "style". "Open" competitions are great because they permit this kind of experimentation and everybody, including the judges and spectators alike, learns something valuable.

What is less easy to smile about is to realize that MOST horse owners in North America are, in fact, riding projects - without realizing it.

The most commonly owned breeds of horse in North America are Thoroughbreds, Quarter Horses, and Appaloosas. Historically, all Thoroughbreds and Quarter Horses were bred for one primary money-making activity, flat racing. Since the incorporation of the Appaloosa Horse Club in the 1940's, most of those horses, especially in the U.S., have also been bred for flat racing.

While it is true that the trend in all of these breeds since about 1960 has been toward finding viable, economically productive uses for individual animals that are not going to have racing careers, all of them, even when crossbred, inherit significant racing character from their ancestors.

It is certainly possible to find individual Thoroughbreds and Quarter Horses that are "off type" for racing – and thus suitable as riding horses. Within Thoroubhreds, the English, Point-to-Point, or Field Hunter type or i.e. what in the U.S. is bred for the one paying race longer than 2 miles, the Maryland Hunt Cup – tends to be well suited for riding, particularly in the matter of overall body balance. Within Quarter Horses, the Doc Bar, Lena, and Poco bloodlines also tend to produce more up-fronted horses with strong, short loins, necks that tend to arch, and a more level fore-aft balance.

With the gradual expansion in the market for riding horses and an increasing need to put retired racehorses or excess production to some other use, the horse industry has developed sophisticated techniques for "converting" these animals for riding use. Over the past century and a half many of these techniques have become traditional, for example, the use of cavalletti and jump gymnastics to teach ex-racehorses how to rate distances and balance themselves over their hocks, skills which no racehorse needs. As a measure of how far we have gone in this direction, I would like to suggest considering the opposite possibility: what reason would there be not to have a match race for money over, say, a mile and a half distance, for a group of promising young Walking Horses? What specific training techniques would be required to teach these animals how to extend and flatten their gallop stride?

Where to Find Horses of Riding Type

The breeds of horse in which most individuals are conformationally suited to riding are those which are of medium to small size, and which have no racing history. These include for example Andalusians, Lusitanos, Lipizzans, Paso Finos, Peruvian Pasos, Criollos, Coralleros, Old Canadians, Mustangs, Morgans, Mangalargas, American Saddlebreds, Tennessee Walkers, and Missouri Foxtrotters. Iberian blood is a prominent feature here, as is the tendency to gaitedness. Collection at all gaits and maneuvers is remarkably easy for these animals.

The Arabian breed produces many individuals suitable for riding, while also producing a significant number suitable for flat racing. Davenport and other Old Egyptian bloodlines, as well as some of the rarer antique American bloodlines, produce short-coupled horses with round bodies, a good cut of withers and shoulder, arched necks that are not too long or fine, and good bone. The Polish and Crabbet lines also produce significant numbers of horses suitable for riding.

The "old type" Appaloosa is also a good candidate for a riding horse - if you can find one. These horses look nothing like either Arabians or Quarter Horses, but instead are tall and somewhat angular, often with a long rather boxy head. They are distinguished by outstanding bone and hoof quality, and a remarkably long, elastic stride. The majority of horses of this type are to be found in Southwestern Canada.

Modern Warmbloods are produced by crossing large amounts of Thoroughbred onto a population originally conformed as another use-type, carriage and harness horses. This use-type, though not outlined in detail here, contains many features desirable in riding horses, particularly strong, wide loins and level or uphill body balance. The purpose for crossing these horses with Thoroughbreds (or occasionally Arabians) has been to reduce the size and bulk of the animals, for being over-large is problematic in a riding horse. Horses that weigh over 1450 lbs. have proven significantly less sound and hardy for riding use than horses that weigh less. Results of crossbreeding to produce Warmbloods are variable, with some beautiful individuals being produced among a large majority of animals which do not find collection, or the maneuvers which flow from it (i.e. passage, piaffe, pirouette, half-pass) particularly easy.

The most highly under-rated and under-acknowledged crossbred in North America today is the Quarab or Quarter Horse X Arabian. These animals are bred by the thousands all across the continent, and I have rarely seen a poor one. They tend to be more levelheaded and easygoing than Arabians, while being much better balanced and having better bone and hoof quality than the Quarter Horse. They are excellent "first horses", being sound, durable, not too large, easy to train and handle, and apt for collection.

Another crossbred that is now becoming readily available in North America is the Azteca. Animals registered in the Mexican breed organization have been produced by a careful process of graded inter-crossing of Andalusian sires on Quarter Horse mares. The resulting animal is similar to the Quarab, but somewhat larger and sometimes with a heavier neck.

The retired American Standardbred trotter can also make a good riding horse, some of them being very similar to American Saddlebreds in build. These animals do require re-training, however: the pacer will have to be helped to either gait or trot (instead of hard pace), and either type needs to be shown that nobody in its new environment is going to punish it if it canters.

The odd crossbred also will make a delightful riding horse. One of the best I ever saw was a Belgian X American Saddlebred, with the sire being the latter. The traditional British product, the Irish Draft, is another good prospect, as is the French Anglo-Arab. Indeed, any horse of any breed, crossbred or purebred, if it possesses the features of Riding horse type, will make a good riding horse.

Posture VS. Structure

A general way to think of posture is "how the horse carries himself" or even "how the horse uses himself." Technically, posture relates to the vertebral column, particularly to the correct alignment of the vertebrae. Static posture is the posture the animal maintains while standing still, and dynamic posture is the oscillation of the animal's back and resultant swinging of its limbs when it is moving.

Let me repeat that last statement about dynamic posture in another form:

Or, in short: back dynamics govern limb dynamics. What the back does predetermines what the limbs will do.

What this means in terms of riding and training is that you must "shape up" the animal's axial body before you can expect the limbs to do what you're hoping and expecting them to do.

Straightness

Another way to think of "vertebral alignment" is as straightness. Straightness is absolutely vital to athletic performance, smoothness, beauty, or even the animal's ability to remain comfortable and calm while working. Since the body is a three-dimensional object, there are three senses in which the vertebral column can be shaped up:

• Lean (side to side straightness: the master dimension)
   
• Rotation (tipping head or tipping pelvis; the second dimension)
   
• Roundness (coiling the loins, raising the freespan of the back, raising the base of the neck; the minor dimension).

For more information on the biomechanics of straightness, and its important (and subtle) connection to calmness and willingness in the horse, please go to www.equinestudies.org and, at the home page, click on the button labeled "Food for All." From there, read all five sections under "Woody" ("Woody" is the name of the model wooden horse that I built to illustrate some of these concepts).

Roundness and Collection

Roundness is the automatic result of straightness in the two more important dimensions.

Roundness is the lowest degree of collection.

Collection is a particular posture, one which best adapts the horse for movement and continuing soundness while bearing weight on its back.

Collection starts from, and is always primarily the product of, coiling of the loins (= "engagement of the hindquarters" in the modern sense). It is continued with the raising of the freespan of the back, and it is completed with the raising of the base of the neck.

Note that head position is not mentioned in the above definitions and descriptions. Neither is "strengthening the topline." Fullness of the topline and the appropriate head position are the results of collection, not the determinants of it. The same may be said for any feature of limb movement – when horses are collected, it is true that they raise and flex their knees and hocks more than when not collected, take shorter steps, progress forward more slowly, etc. It is unwise to focus on secondary effects. Focus on the determining posture instead, and you will almost automatically have all you desire and more -- and a horse that is sound and happy into the bargain.

Rate of Skeletal Maturity

This has been a really hot item for discussion on our website at www.equinestudies.org. What we call "the Ranger piece" on skeletal maturation has now been requested and reprinted in over 50 different publications worldwide. To review the complete discussion, at the home page click on "Q/A Forum," and when you arrive there look for the hot button at the top called "conformation analysis." Once there, scroll to the bottom and read the discussion of the young horse named Ranger.

Just a few points from that article are summarized here:

• No horse, of any breed or bloodline, is mature before the age of 5 ½.
   
• The earliest-maturing horses are small, scrubby, range-bred mares.
  Male horses tend to lag about 6 months behind female herd members kept under the same circumstances. Good feeding tends to prolong growth and delay maturity.
   
• No horse is skeletally mature at age 2.
  There are both advantages and disadvantages of starting horses at age 2 or earlier. Unless there is a compelling economic reason, I advise waiting to start young horses undersaddle until they are 4.
   
• There is more than one "growth plate".
  The one growth plate that most people know about is the one "at the knee" (actually, at the bottom of the radius-ulna bone just above the knee). Every bone in the skeleton outside the skull contains at least one growth plate. Each limb bone has one at the top, one at the bottom, and may have others (on prongs or projections such as the tip of the elbow or the third trochanter of the femur).
   
• Maturation follows a definite pattern.
  Individual portions of the skeleton become mature when the growth plate nearest them fuses to the bone shaft. There is a schedule for this over the horse's body: the lower down in the limbs, the earlier in life the growth plates fuse.
   
• The last parts of the skeleton to become mature are the vertebrae and teeth.
  The last teeth erupt in a male horse at age 5 ½ to 6. The last vertebral growth plates also fuse at about this age, or later.
   
• The slowest-maturing horses are tall, long-necked individuals.
  Largeness itself tends to delay maturity, and long-necked horses tend to have the caudal cervical plates fuse quite late, even up to age 8.
• Early riding can damage either the young horse's limbs or its back, although gross damage is rare. Subtle damage, which may only show up on X-ray, or which may show up even years later, is very common.

  Nevertheless, the main reason to avoid riding the 2 year old or younger horse is not to preserve its bones but to preserve its posture: young horses readily learn to clamp their back muscles to "defend" against the rider's weight, whereas 4 year olds and up rarely feel an instinctive need to do this. Not having learned to clamp their backs, these horses produce roundness and collection with much greater ease.

  Owners can and should learn how to handle young horses, and can teach them many things which build skills, muscle, and postural habits good for riding. Such a program starts with the foal's first lessons in haltering, leading, and having its feet handled.

Links to Images

Image 1 - Horse Skeleton (26kb)	Image 2 - Palpation Points for Conformation Analysis (18kb)	Image 3: Fig. - Perfect (20kb)	Image 4 - Primitive (18kb)
Image 5 - Pathological (19kb)	Image 6 - Pathogenic (21kb)	Image 7 - Areas of Bone Formation (36kb)

.Additional References

For more information on a wide variety of horsemanship, anatomy, and biomechanics topics, as well as many useful horse-related links, please visit the Equine Studies Institute website at www.equinestudies.org. The Institute also carries book reviews, used horse books, a huge annotated bibliography for further reading, and new books. Dr. Bennett's three available works, which include Principles of Conformation Analysis, Conquerors: The Roots of New World Horsemanship, and The Birdie Book: An Internal Geography of Horse and Rider, are described in the Institute website with information for ordering. Some of the illustrations provided in this article appear in Principles of Conformation.

Equine Studies Institute
P.O. Box 411 Livingston, CA 95334
www.equinestudies.org
Phone: 1-800-952-5813 or 1-301-977-3900 .

About the Author

Author Deb Bennett, Ph.D., is Director of the Equine Studies Institute in Livingston, California. She is a frequent contributor of articles on conformation evaluation in horses in several equine magazines, and is the author of several books on conformation and horsemanship. Dr. Bennett also teaches unique equine anatomy short-courses designed primarily for owners, trainers, therapists, and breeders.

This information was presented at, and appears in the Proceedings of, the 2002 Alberta Horse Breeders and Owners Conference.

The author, Deb Bennett, retains all rights under international copyright 1999-2002 law to the text and illustrations included in this article. Reproduction of this information, in any form, without the expressed consent of the author is prohibited.Deb Bennett, Ph.D.Equine Studies InstituteLivingston, California