Last Updated on February 28, 2022 by Allison Price
The horse’s ability to stay healthy and fast depends on the condition of its feet and legs. The front legs are heavier than the hinds, and they are more susceptible to stress and concussion. Faults in conformation in the front legs could have worse consequences than those in the hind legs.
Speed, athletic ability, and soundness are all dependent on conformity
The front legs are heavier than the hinds, and they are more susceptible to stress and concussion. Faults in conformation in the front legs could have worse consequences than those in the hind legs.
The length of a stride is determined by the foreleg conformation (from the shoulder to the hoof). The front legs’ primary function is to support the majority of the horse’s body weight, absorb shocks from concussion and lift the body during the flight phase. The strongest construction is composed of straight legs, strong bone structure, large flat knees and well-shaped feetlock joints.
Straightness
The ideal forelegs should be straight. Forearms should be directly above the cannon bone cannon bones. Cannon bones should be at right angles to ground from either side or front. Both legs should be equally weighed. Toes should point towards the front and hoofs should be at the same distance as the distance between forelegs and chest.
The line should be drawn from the point of your shoulder and run down the middle of the front leg. It should intersect forearm, knees, cannon, fetlock joints, pastern, hoof, and cannon. If you are looking from the side, a line should be drawn from the front of your withers. It should run down the middle of your front leg (side view), and just barely touch the heel of your foot. If the line that runs from the front of the horse’s withers to the middle touches the heel, it is likely that the horse has a forward shoulder.
Horses aren’t always perfectly straight. If they are not too distracting or slowing down speed or soundness, and symmetrical on each leg, some faults can be accepted. Remember that horses rarely have their bones and joints perfectly straight and that there are no exact matches between front legs. There will be slight differences even on the same horse; the left leg is rarely the exact match.
Straightness of foreleg
The line should be drawn from the point of your shoulder to the middle of your front leg. It should cross forearm, knee and pastern.
One or both of the foreleg bones may be slightly off at the knee or at the fetlock joint. It is important to be able assess whether the leg structure is straight or crooked and to determine how it will affect horse’s movement, speed and agility as well as future soundness.
Base wide
This can occur anywhere from the elbows to the fetlock joint. Turned elbow causes the leg to turn inward. Horses with narrow chests also have a base wide structure. Splay-footed horses with a wide base are more common than those with narrow chests. This causes the feet to break to the inside and inwardly, sometimes leading to interference (striking the other leg).
Because they are narrow at the chest, foals tend to sag slightly. As they get bigger and more muscular, their chests will become wider. They tend to be straighter as they age. Because the chest muscles are not affected by the amount of weight, splay-footed children are more likely to straighten as they get older than pigeon-toed foals (toes inward), which can cause a change in their toe-in position.
The inside of a horse with a wide base is more stressed than if they are splay-footed and base wide. The ligaments and pasterns at the inside of the horse’s fetlock joints are always under strain. Windpuffs, or swellings of the fetlock joints, are common in horses who work hard. Extra fluid may be required to keep the tendon and joint capsules hydrated. On the inside of your feet, you may notice ringbone or sidebone.
The cannon bone and the knee joint’s inside are more stressed and subject to concussion. This makes it more likely that the horse will develop splints in the inside of his leg. Because the hoof gets more wear, it is often worn too much on its inside. Splay-footed horses tend to wing their feet towards the inside, regardless of whether they’re base wide or narrow. This allows them to pick up the foot from the inside. Some horses have pigeon toes and are also base-wide, which places more strain on the lower leg.
Base narrow
Horses with their feet too close together will often have large pectoral muscles, and a broad breast. Pigeon toes are often paired with a narrow base. This places strain on the joints and can lead to windpuffs, ringbone or sidebone in the outside portion of the feet. Because the hoof wall is worn too much on the outside, the feet tend to break off from the outside and land more hard on the outside.
Pigeon-toed horses with a narrow base generally paddle by swinging their feet outward. This causes wasted motion because the lower leg and foot are flung to the side at every step, reducing speed and agility. Pigeon-toed horses can paddle regardless of whether they are base narrow or wide.
Some horses are narrower than others and have splay feet. This puts more strain on the limbs below their fetlock joint. If they are being used too hard, they can become lame. Because the feet are inwardly positioned and the feet wing inward, the splay-footed base horse will strike by itself. Aplaita is when he puts one foot ahead of the others. This can cause poor balance and instability, as well as a horse’s potential for falling if his front foot strikes another leg.
Upper arm
From elbow to shoulder, the arm bone (humerus), runs from the elbow to the shoulder. This bone’s length and angle have an impact on the action and stride. It determines how tight the elbow and leg joints can bend (bend), and how far forward the whole leg can extend when the horse moves. The attached muscles will benefit from more power and strength if the humerus has a longer length. An additional length in the front leg increases its range of motion, creating a larger arc at the elbow’s lower end.
Showing humerus in relationship to scapula/shoulder and elbow
A longer humerus increases strength and power, and also allows for greater motion in the front legs.
For speed, a long humerus can be desirable. However, it shouldn’t be too long relative to the shoulder blade. This could lead to relatively short shoulder muscles which would limit the movement of your upper arm.
If the humerus measures 50-60% of the length of your shoulder blade, it is considered desirable. This places the elbow below the withers. If the humerus extends beyond 60% of the length of the shoulder blade it is considered too long. This limits freedom of action.
Conversely, a too short humerus can cause a horse to have a short and choppy stride. An arm bone that is too short is often horizontal and has a lower angle than the shoulder, which makes it less than 90 degrees. Because of the choppy stride, this increases concussion to your leg. Although this isn’t a problem for sprinters, horses with this type of conformation can tire if they try to keep up high speeds for too long.
The humerus should be horizontal to ensure maximum speed and endurance. Otherwise, it will restrict the movement of the elbows as well as the swing of your leg. The angle between the humerus and the shoulder blade should be equal to the angle between the pelvis and the femur in the hindquarters. A well-sloped shoulder will usually be accompanied by an upright humerus. Conversely, a short, steep shoulder will often go hand in hand with a more horizontal, longer humerus.
Forearm
Between the elbow and the knee, the forearm should be long, thick, and wide with well-developed muscles. These muscles are crucial for speed and should be larger at the top than at the bottom. They taper to the tendons at your knee. The muscles should be long and smooth for endurance. They shouldn’t be twisted up or short. The forearm should be long, as it houses the muscles, and the cannon bone should be short.
From shoulder to knee
Between the elbow and knee, the forearm should be long, thick, and well-developed. You should also look for bigger muscles that taper to the tendons at your knee.
Long forearms allow for more muscle length and shorter tendons. This creates better leverage for faster and easier leg movement. A longer forearm means a greater arc and a longer stride. The horse will need to work harder if the forearm is shorter. However, the horse will be able to make more movements in the same time.
Knees
The joint should be well proportioned, large and flat at the front. A narrow, pinched-in knee can block the tendons from their cartilages and prevent them from moving freely. Concussion can also be increased if the knee is too small. Flat fronts allow the extensor tendon to glide across a smooth surface as they straighten each leg.
The cannon bone should be below the knee and the forearm. The horse may be calf-kneed (backward at the knees) if the cannon is too far back. This will cause the leg to look concave from the side.
Horses who are abused can put more strain on their tendons with each stride. This structure can also cause more concussion and over-extension (bent towards the rear) of the joint, which could lead to carpal fractures.
Over-at-the-knees is another fault, also known as buck knees. This could be an inheritance defect, or because of overwork. Because the knees are more flexible and bend forward, a horse with buck-kneed is more likely to stumble.
Horses that are out-at the-knees (bowled when viewed from front–carpal varus), often have narrow base and pigeon-toed conformation. This places extra strain on the outside ligament, the inner portion of the knee bones and the outside portion of your joint capsule. Horses with too close knees will have in-at the-knees (carpal vagus, also known as knock kneed). The lower leg can angle outward, creating strain on the knees and joints.
If viewed from the side there are other deviations from good leg conformation. Tie-in-at the-knee is when the flexor tendon is too close to the cannon bone below the knee. This prevents free movement. This indicates that the tendons may be weaker than they should and are often too small. Because the tendons pull inwardly against the knee rather than pulling down from the side, the muscles above the knee have a decreased leverage.
Cannons
There is a smaller splint bone at the back of the cannon bone, between the knee and fetlock joints. When viewed from the front, side, or back, the cannon bone should look straight up and down. The forearm muscles continue downward (below your knee) and the long tendons behind the cannon bones allow you to flex or extend your lower leg.
For best leverage, an athletic horse will have long forearms with relatively short front cannons. The cannon and its associated tendons should not be too long. This puts more strain on the tendons, and makes them more susceptible to injury. Horses’ leg muscles will tire faster when they do hard work, because there is less muscle (forearm), and more weight (cannon bones) to support the work.
If the cannon is viewed from the side, it should look wider than it does from the front. A flat lower leg has a lot more depth from the front to the back. This term refers to a combination bone and tendon. The tendon is set back from the cannon bone, rather than directly next to it. Too much friction between moving parts can result from tendon and bone being too close together (around a bone). The leg will not hold up.
Pastern and joint fetlock
The joint between pastern and cannon should be wide from all angles. It should be rounded at the front, but flat on all sides. The joint should align with the cannon and pastern above it. The pasterns should be moderately sloped, with enough length to dissipate and give concussion.
Moderate slope of pasterns to dissipate the concussion
The pastern and hoof angles should be identical.
However, too much slope can put too much pressure (from the tendons and ligaments on the sesamoid bone at the back of your fetlock joint) and cause a weak pastern. This could lead to the horse slipping when he tires. The horse will experience a choppy, jarring gait due to the lack of slope. He will also suffer from increased concussion, which can cause damage to his feet and legs.
Too long pasterns reduce speed potential because it takes more effort to push off at each step and get the foot up the ground. Too-short pasterns are almost always too upright and cause a pile-driving, pounding effect. It is a good rule of thumb to keep your pastern shorter than the cannon bone. This increases the chance of concussion injury, and creates a shorter stride.
Horsemen believe that a shorter pastern is better for propulsion, especially for quick starts. However, it must be steep enough to absorb concussion. Horses can cope with either sloping pasterns or ones that are long and steep. The opposite combination (short and steep or long and slope) can cause problems.
Sidebar: Dissipating concussion
The impact of the foot striking the ground with fast gaits can be offset by how a good foreleg is constructed and moves. This distributes the stress so that no part is more stressed than the other.
The distribution of trauma from concussion will be more uniform if the joint and leg conformation is closer to ideal. The main shock-absorbing factors for the front leg are movement within the compound knee joints (two rows small bones between forearm, cannon), and pumping action from the foot.
The pastern’s action transfers some strain from the legs to the tendons and the tendons, which in turn transfer it to the elastic muscles of your upper leg. The shoulder blade glides across the ribs and transfers any shocks (not taken up) to the body.
If the front legs were straight like a pipe, with no shoulder or pastern slope, the impact from each step would travel directly from the ground to your body. This jarring stress can be dissipated if the shoulder, foot and pastern are properly aligned.
