Having a helper jog your horse makes it much easier to watch for tell-tale head bobs. ©EQUUS Magazine

One obvious sign of lameness is a rhythmic bob of the head as a horse walks or trots. But pinpointing which leg is sore can be difficult.

The bobbing motion is produced when a horse uses the mass of his head and neck to shift his weight away from his sore leg with each stride. In general, if the horse’s head bobs more upward than downward, the lameness is likely to be in a front limb: The head rises when the affected leg bears weight and dips when the sound leg is on the ground. If, however, the horse drops his head dramatically with each stride, the source of the lameness is more likely to be in a hind limb: As he trots, he drops his head when the foreleg diagonal to the sore leg is touching the ground.

To better identify the limb that hurts, have a friend jog your horse over a flat, smooth surface while you stand about 20 feet away, perpendicular to their path. Ask your helper to leave the lead line slack so that your horse’s head is not restricted. As the pair jogs past, keep your eyes straight ahead and let them cross your field of vision, keeping the entire horse in perspective. If you follow the horse with your eyes, you may focus too closely on a single leg and reach the wrong conclusion. You may need to watch the horse pass several times to determine which leg is affected, and mild lameness may be noticeable only when the horse is turning.

Share your observations with your veterinarian when she arrives to examine your horse. She will do a more thorough diagnostic investigation to pinpoint the source of the trouble.

Your veterinarian will palpate the full length of each leg for any heat or unusual swelling, often comparing from side to side.

Step 1: Observation
During a lameness exam, your veterinarian will first observe your horse from a distance. He or she will observe your horse from the front, behind, and both sides to look for muscular asymmetry.

Here’s why: Your horse is a master compensator. If he begins to develop soreness in one location, he’ll compensate for it with subtle changes in how the leg is moved, how a foot might land, or by redistributing weight. These changes will often show up in your horse’s resting posture, as well.

Few horses stand perfectly squarely all the time, but most, when standing quietly, will settle into a posture that feels right to them. Assuming they have a good trim and are receiving the correct information from the ground, they should stand squarely.

If your horse is sore, observable changes at rest might include not standing squarely, e.g., feet positioned in front of or behind the spot that would be perpendicular to the ground; preferentially resting a limb; and weight shifts.

Step 2: Touch
Your veterinarian will then move in closer for a hands-on exam. He or she will palpate (explore by touch) your horse’s muscles for tone.

A relaxed muscle at rest — even in a very fit horse — has the same consistency as a roast of beef, although the postural muscles along the spine have somewhat higher normal resting tone, because they are “working” to hold the spine in alignment even when standing still.

The gluteal muscles of the rump are also somewhat difficult to evaluate, because the skin there is very thick and tight, with a generous layer of fat between skin and muscle. If muscle tension/hardness or sensitivity to touch is found, carefully note the location.

Next, your vet will carefully check the full length of each leg for any heat or unusual swelling, comparing it to the opposite side if there’s any question. He or she also will note any unusual prominence to the veins from side to side, which often indicates inflammation.

This part of the exam also includes picking up the foot to inspect the sole and frog, check hoof wall temperature, and compare the hoof temperature to the rest of the leg. Each joint will be gently and gradually flexed, looking for any sign of pain (such as your horse pulling back).

Your vet then will use hoof testers (pliers with large, rounded jaws) to check for hoof sensitivity. This test can reveal such conditions as a sole abscess, laminitis, or a stone bruise.

Step 3: Sound in Motion

During a lameness exam, your veterinarian will observe and listen to your horse moving. You can hear a softer landing on the sore leg, with louder sounds as your horse shifts weight to compensate.

During this step, your veterinarian will watch and listen to your horse moving from the front, back, and side. He or she will observe and listen first at the walk, then at the trot and on a circle if nothing is obvious at the walk.

To tell where your horse may be “off,” first develop your ear! Practice listening to the clip-clop noise made by your horse at the walk and trot. A sound horse lands with equal force on each foot, slightly louder in front than behind.

When your horse has pain, you can actually hear a softer landing on the sore leg, with one or more louder sounds as he shifts weight to compensate. His gaits will also lose their rhythmic sound as he rushes to unload the sore leg and more quickly stomps down the compensating legs.

If your horse has a Grade 2 lameness up front, he’ll often just shorten up his stride at a walk, but move with an even stride length from side to side. This makes it very difficult to detect.

With a hind-end lameness, your horse is more likely to shorten stride only on the sore side. In addition, he’ll look “disconnected” front to hind. Toe dragging/scuffing, sometimes to the point of stumbling, is another common sign of pain.

Step 4: Flexion Testing
This testing method is still a valuable diagnostic tool, but is falling out of favor somewhat since it’s possible to make any horse move off badly if you crank on the joint too much.

The amount of flexion or extension you’re able to impose on a joint isn’t necessarily the same as how far it was meant to move. To see what I mean, practice manipulating the joints of your own hand. Hold a finger straight, then force it front and back. You’ll feel pain when you force it beyond where it would normally go.

If your horse seems to be objecting to a flexion, your veterinarian may go to the other side to see how your horse reacts to the same flexion. Or, your vet may walk your horse a few minutes to let him relax.

Note that if your horse appears to be in pain during a flexion text, the real cause may actually be the extra weight the opposite leg is carrying.

Step 5: Nerve Blocks
Unless there’s a glaringly obvious problem, such as a bowed tendon, nerve blocks (perineural analgesia) are typically the next step in a lameness examination. By numbing select leg structures, your veterinarian will better be able to track down the source of your horse’s pain.

The blocking begins with the paired digital nerves at the back of the pastern. Called a low volar block, this will take out most of the foot, including the hind foot and the sole, part of the coffin joint, and part of the pastern joint.

The anterior (back) portions of the foot and pastern structures are supplied with the nerves that branch off from the digital nerves at fetlock level. Therefore, to completely block the foot, the nerves are blocked at fetlock level — called a high volar block. The only problem with a high volar block is that it’ll also anesthetize the fetlock.

An alternative to the high volar block is a ring block, where anesthetic is injected under the skin of the upper third of the pastern, in a line across the anterior (front) 180 degrees of the bone column.

Step 6: Joint Blocks
When the fetlock, knee, shoulder, hock, stifle, hip, or sacroiliac joints need to be anesthetized, the usual procedure is to inject directly into the joint. Joint fluid is usually withdrawn first, which can be studied for further clues.

The hock and knee can also be blocked. Other areas commonly blocked are the origins of the suspensory ligaments, bursae, and the sacroiliac region.

Lameness Scoring System
The American Association of Equine Practitioners has developed a system for scoring lamenesses:

0  Lameness not perceptible under any circumstances.

1  Lameness is difficult to observe and isn’t consistently apparent, regardless of circumstances (e.g., under saddle, circling, inclines, hard surface, etc.).

2  Lameness is difficult to observe at a walk or when trotting in a straight line but consistently apparent under certain circumstances (e.g., weight-carrying, circling, inclines, hard surface, etc.).

3  Lameness is consistently observable at a trot under all circumstances.

4  Lameness is obvious at a walk.

5  Lameness produces minimal weight bearing in motion and/or at rest, or a complete inability to move.

Photos by Dusty Perin

The concept of leads at the canter or lope is simple enough:When a horse is on the correct lead, he starts each stride with the outside hind leg and ends it with the inside foreleg. Riders cue their horses to encourage this sequence and quickly learn to recognize by sight and feel when a lead is wrong. Returning to the trot and asking for the canter again usually remedies the situation right away.

When a horse consistently picks up the wrong lead, however, it’s easy to get frustrated. There are many tricks and techniques for getting a horse to take a particular lead, but these ignore an important reality: A horse who consistently picks up the wrong lead probably has a physiological reason for doing so.

Horses naturally want to canter on the correct lead because it helps them keep their balance. The trailing (outside) foreleg at the canter or lope resists the centrifugal force that pulls the horse to the outside of the turn. If you watch horses play in the pasture, most will choose the correct lead when cantering through tight turns or switch to it at some point to steady themselves. And even in their early under-saddle experiences, young horses will tend to pick up the correct lead naturally.

When a horse always resists cantering on a particular lead, it’s usually because it’s physically difficult or painful to do so. Lead problems may result from discomfort or stiffness anywhere in the legs, body or back. Many times the horse isn’t overtly lame at the walk or trot, and he may even be able to pick up that lead at liberty with little problem without the added weight of a rider, but it’s still a physiological problem and not a training issue. Likewise, lead problems may signal a malfunction in the neurologic system.

If your horse is having lead issues, set aside training until you’ve had your veterinarian and farrier weigh in on the problem. Identifying and correcting any lameness or neurologic issues, which may take several months or weeks, is the only sure-fire way to help your horse.

No one would fault you for thinking the worst if you discovered your horse standing in his field, unwilling and unable to walk even a step. But before you panic, take a closer look and consider the possibility of radial nerve paralysis rather than a broken leg.

Radial nerve paralysis occurs when a kick or other blunt blow traumatizes the long radial nerve, which runs down the front of a horse’s shoulder. It can also develop after a horse is anesthetized in a position that compresses the nerve for a lengthy period of time. Damage to the radial nerve leaves the horse unable to advance the leg, and horses will often stand with the shoulder of the affected leg “dropped” with that hoof knuckled over to rest on the toe.

If you find your horse standing in the field with a dangling leg, first—obviously—check for open wounds or other signs of fracture. Also observe the horse’s demeanor. Radial nerve paralysis isn’t particularly painful; if the horse appears agitated or in pain, call the veterinarian immediately. If all looks well, very, very carefully attempt to place the hoof of the “limp” leg flat on the ground. If the horse allows you to do so, you may be dealing with a case of radial nerve paralysis. Call the veterinarian and let her know what you’re seeing.

The prognosis for radial nerve paralysis depends on the extent of the nerve damage. Mild cases may resolve in a matter of days with anti-inflammatory medications and DMSO. Your veterinarian is likely to wrap the affected leg as well as the opposite limb to ward off laminitis. Severe cases of paralysis, however, in which the nerve has been completely severed, can take months to heal or may never improve at all.

With all the headlines about equine herpes virus and other neurologic diseases, it’s easy to get paranoid about any misstep your horse takes. However, rest assured that most stumbles are not indicative of a serious problem.

In horses, the first signs of central nervous system trouble are more likely to be weakness or gait asymmetry. A neurologically impaired horse will drift sideways, with his hindquarters out of alignment, instead of walking straight. He will also have a less-than-perfect awareness of the position, movement and orientation of his limbs (known as proprioception), and will tend to step on himself, particularly if led in a small circle or pushed sideways.

Once a horse with neurological disease gets to the point of stumbling, his condition is so advanced that it’s clear that more simple clumsiness is the cause. If you're still worried, try two simple tests:

• With your horse standing still, cross one of his forelegs in front of the other. A horse with full neurological faculties will be able to easily uncross them.
• Raise your horse’s head as high as you can and ask him to walk backward. A horse with a neurological deficit will not be able to comply and will “sit” or scramble rather than back up.

Deciding whether to give your horse a joint supplement is easy, but deciding which specific product to use can be exhausting. There are literally hundreds of options---shelves, catalog pages and websites filled with powders, liquids and pellets all designed to maintain the health and function of equine joints.

How do you sort through them all? Start by reading the labels to see what they contain. Although all  joint supplements have the same intended action---supporting the health of cartilage0 and synovial0 fluid to keep your horse moving with ease---they are formulated with a variety of ingredients. Some components are found in the majority of joint products; others appear in only a few. Learning even a bit about each one will give you a better idea of how a specific product may help your horse.

Here’s a closer look at some of the ingredients commonly used in joint supplements. Use this list as you shop to gain a better understanding of the various joint-support mixtures available. If a product doesn’t list ingredients on its label, do some investigative work. Many supplement companies have nutritionists who can answer your questions and, of course, your veterinarian is a great source of information and guidance about what your horse needs.

Avocado/soybean unsaponifiables (ASUs) are extracts from soybeans and avocados that prevent destruction of existing cartilage while stimulating cell tissue and repair. In France, ASU is available by prescription to treat arthritis. Recent studies in this country suggest it is effective in reducing the severity of arthritis symptoms.

Boswellia, also known as frankincense, is an extract derived from the gum resin of Boswellia serrata, a tree native to India. In traditional Ayurvedic medicine, boswellia is used to treat asthma, colitis and arthritis. The primary component of the extract is boswellic acid, which studies show has anti-inflammatory effects through several actions. It is usually combined with other herbs in joint supplements.

Cetyl myristoleate is a fatty acid with anti-inflammatory and immune-modulating properties. An important component of synovial fluid, cetyl myristoleate was discovered by a National Institutes of Health scientist who observed that a certain family of mice seemed immune to arthritis. It can be derived from beef tallow or wild nutmeg. It is a relatively new addition to equine joint supplements.

Chondroitin, also called chon-droitin sulfate, is a large protein molecule that helps give cartilage its elasticity. This molecule is also thought to inhibit enzyme activity that can break down cartilage as well as stimulate production of synovial fluid. Chondroitin isn’t found in the normal equine diet and is typically manufactured from animal products high in connective tissue, such as bovine tracheas or cartilage. It is often paired with glucosamine in equine joint supplements.

Devil’s claw is an extract from the roots of a plant native to southern Africa. Its botanical name, Harpagophytum, means “hook plant” in Greek, a reference to the protrusions of the seed that attach to an animal’s coat and allow it to be spread. Devil’s claw has been used for thousands of years to treat fever, gout, arthritis and digestive disorders. Studies suggest that devil’s claw is as effective as some pain medications in reducing the pain of arthritis.

Glucosamine, which occurs naturally in the joint fluid, is one of the building blocks of cartilage production and repair. Research suggests that it may also help control inflammatory processes associated with arthritis. For use in supplements, glucosamine is extracted from chitin, a substance found in the shells of lobster, crab and shrimp. Glucosamine is often combined with chondroitin in oral supplements for horses.

Grape seed extract is added to many human supplements to combat heart disease, high blood pressure  and high cholesterol. Several current scientific trials are assessing whether grape seed extract can help inhibit tumor growth. It is included in equine joint supplements because it is also a source of oligomeric proanthocyanidins, an antioxidant thought to aid in the repair of collagen.

Hyaluronic acid (HA), also called sodium hyaluronate, is a component of synovial fluid, which lubricates joints and forms the matrix of the articular cartilage that covers the ends of long bones. It may also help to protect these tissues from the destructive effects of inflammation. One of the earliest applications of HA in human medicine began in the late 1970s, when it was used as a lubricant for the eye during surgical procedures. The use of HA to treat and prevent osteoarthritis in horses and people soon followed. Just a few years ago, HA was available only as an injectable product, but it is now a common ingredient of oral joint supplements.

MSM (methylsulfonylmethane), a naturally occurring compound derived from DMSO (dimethyl sulfoxide), is found in small amounts in alfalfa. An organic source of sulfur, MSM helps give collagen stability and strength and enhances the function of glucosamine. MSM may also have anti-inflammatory properties. In addition, research has been done into the potential of MSM for controlling hay fever and snoring in humans with varying results.

Omega-3 fatty acids are commonly found in marine and plant oils. Although omega-3s have long been touted as helping to prevent cardiovascular disease, they have been shown to have some anti-inflammatory action as well. Flaxseed and linseed are high in omega-3s and have been a traditional feed supplements on racetracks for decades. Supplements that contain flaxseed or flaxseed oil are intended to provide the same level of omega-3 without the preparation of boiling or grinding the seeds yourself.

Phenylalanine is an amino acid that is thought to help preserve enzymes that block chronic pain, making it popular in supplements targeting arthritis in horses. You may see phenylalanine listed in different forms on a supplement label: D-phenylalanine is a synthesized version of the natural form, L-phenylalanine, and DL-phenylalanine is a combination of both of these.

Silica is a trace mineral. Although it’s most abundant in sand, it is also present in plants to give them structure and, therefore, is found in your horse’s diet in small amounts. At the molecular level, silicon is involved with the formation of articular cartilage and connective tissue. Research has found improved bone development in young horses supplemented with silica, making it a popular addition in joint supplements.

Vitamin C (ascorbic acid) is a water-soluble vitamin and antioxidant. It is required to synthesize collagen and connective tissue and acts as a scavenger of free-radical molecules that can damage tissues. Unlike people, horses produce their own vitamin C and oversupplementation can interfere with that process, leading to a deficiency.

Yucca is extracted from the roots of the yucca, a flowering desert plant native to the American Southwest. It is a source of saponins and polyphenolics, natural chemicals that have anti-oxidant and anti-inflammatory action. Yucca has been used for centuries to treat circulatory and intestinal problems in people.

Last fall I wrote on “Vegas,” Turtle Powell’s standout head horse, and his medical problems, including laminitis. This column is an update on Vegas, courtesy of Turtle and Vegas’ farrier, Blaine Chapman, with some general comments along the way on laminitis in horses, aka “founder.”

Vegas’ problems started last summer with a respiratory infection that had as a consequence a vascular disease (purpura hemorrhagica) and ultimately resulted in significant laminitis. General comment number one: Laminitis can result from a variety of causes. Laminitis literally means inflammation of the lamina. The lamina are the interlocking structures that form the weight-bearing bridge between the inside of the hoof capsule and the corium (covering) of the coffin bone. These cause symptoms of laminitis, which I'll discuss below.

When these structures become inflamed they swell, exude serum and functionally the connecting bond gives way to the stress of weight-bearing and they fail. Efforts to minimize the damage become the objective in dealing with this condition. These efforts include systemic medications, local treatment (such as soaking the feet) and supportive measures to try and stabilize the anatomical structures of the foot. General comment number two: It takes a dedicated team of owner and specialists in the field to have a chance for success in significantly impacted horses with this condition.

Turtle related that the most discouraging days were right before he left to go to the NFR (Wrangler National Finals Rodeo) last December. Vegas had basically been lying down for two weeks. He was eating and drinking well, but would not get up. Turtle called in Blaine Chapman, a horseshoer he knew who has had a lot of experience in dealing with this condition. Blaine encouraged Turtle to wait out the bad spell because, considering the severity of Vegas’ founder, his state was to be expected.

In this horse’s specific condition, it was decided to resect (remove) the anterior hoof wall, which was known per radiographs to have already separated from the coffin bone, plus using special supportive shoeing as the basics of treatment. General comment number three: This example pertains to the circumstances of this specific case. There is no “one size fits all” or singular approach to treating this condition.

This photo shows the anterior hoof wall having been resected. The bottom of the shoe is specially designed to support the coffin bone during the healing process. (It takes six months to a year for the hoof wall to grow from the hairline to the ground.)

Photo courtesy Turtle Powell

Laminitis has received a good deal of attention and study in the last few decades. To this point, there has not evolved any “silver bullet” treatment regimen for the problem. It should be treated as an emergency, but unfortunately, by the time one notices symptoms of painful feet there is already the start of degenerative changes in the critical areas of the foot. We continue to wish Vegas the best possible progress, and will keep tracking his condition as he is no doubt one of the great ones.

Here, I’ll give you five ways to detect lameness: (1) Look for nonspecific signs (physical and attitudinal changes); (2) look at the whole horse; (3) watch your horse move; (4) listen to his footfalls; (5) feel for under-saddle clues; (6) observe his feet.

6 Ways to Detect Lameness

Lameness can be definitively diagnosed only by your veterinarian, but the detective work of the diagnosis is best performed as a team. Flexion tests are a great way for your veterinarian to check for joint pain in your horse.

Lameness Check #1: Look for Nonspecific Signs
Nonspecific signs don’t tell you what’s wrong with your horse, or even if it’s a lameness issue. They do tell you that it’s time to take action to figure things out. These nonspecific signs include:

Lameness Check #2: Look at the Whole Horse
When you decide something is bothering your horse, take time to look him over closely from head to toe. Observe him at rest in his stall and on turnout. Does he habitually point one front leg forward, or rest one hind leg more than the other? Does he stand with his elbows turned out? Does he stand with his toes or stifles rotated out behind? Does he stand with all four legs squarely perpendicular to the ground?

Starting at his head and ears, run your hands over your horse’s whole body and down each leg. When you run your hands over certain areas, note if he shrinks away, flicks his skin, pins his ears, kicks, etc. Check for any obvious swelling or heat.

Observe your horse from the front, sides, and back when someone is at his head and he’s standing squarely. Look for any differences in how well your horse is muscled from side to side. You’ll often see smaller, less well-defined muscles if there’s pain in the associated leg. Localized areas of muscle tension (muscles will feel hard) are also commonly found when a horse is hurting somewhere.

Check your horse’s feet. When there are longstanding painful conditions in a front leg, the hoof on the painful side will often be smaller than the opposite front. When painful conditions involve the front or back legs, you may see shoes/hoof walls wear more quickly on the comfortable side than the sore one, and wear patterns may be different.

When you groom your horse, watch his back — especially his lumbar area as shown here — for skin flickers or muscle flinches. These may indicate back pain of some type, which could translate to lameness.

Lameness Check #3: Watch Your Horse Move
Watch your horse move in a circle, going both directions, first free of tack, then with tack but no rider, and finally tacked up with a rider.

Lameness tends to be exaggerated when a horse is moving in a circle and is easiest to spot at the trot. If the tack itself is bothering your horse, you may be able to see this difference in how nicely he moves with and without tack, especially if you’re careful to tightly cinch the saddle.

Carrying a rider’s weight can worsen a horse’s lameness for several reasons: a saddle-fit problem may be made worse; more weight is put on the horse’s front legs; the hind end has to work harder to move weight forward; it’s difficult for the horse to make subtle changes in how he carries his weight.

First, observe your horse at the walk. Does he look relaxed? Is he swinging freely through his back, shoulders, and haunches, and is he taking smooth, generous strides? Are his head and neck moving in rhythm with the walk? Are his ears pricked? Does he bend smoothly on the circle in both directions? Does he move the same in both directions? Observe the same things at the trot in both directions.

Then tack up your horse, and note any differences with and without a rider. Horses that move in a stiff, wooden way are uncomfortable somewhere. After observing your horse move on a circle, watch him from directly in front, directly behind, and from the side at both the walk and trot. Watch him on both a soft and a hard surface. From the front, check to see if he has normal head movements and if he’s landing evenly with his feet. Is he flexing his knees as high on both sides? Is he dragging a toe or stumbling?

From behind, watch your horse’s rump to see if it rises and falls equally from left to right. Check to see if his back legs move forward in a straight line, swing in before the foot lands, or swing outward before landing. Does the hock flex smoothly or with an obvious “wobble”?

Watch from both sides. Does your horse bring his hind legs forward so the hooves land in (or even beyond) the print of his front hooves? If not, he’s short striding behind. If only one leg is doing this, that’s usually the painful one. If both legs are doing it, then he may be painful in both hind legs, or his pelvis, rump, or back.

Does your horse flex all joints evenly? Watch his fetlocks when each foot contacts the ground. Are they dropping the same amount on both sides? If not, he’s not carrying his weight evenly from side to side. The fetlock that drops the most is taking more of the weight.

Compare the diagonal legs. A horse with a problem will often distribute more weight to the diagonal front or back leg. For example, a horse with pain in the left front may drop his ankle more in the right front and the right hind.

Lameness Check #4: Listen to Your Horse’s Footfalls
Learn to “see with your ears.” When moving your horse on a hard surface, you’ll be able to hear subtle differences in how hard he’s landing. Close your eyes, and concentrate on listening to the sound of his feet striking the ground. Each footfall should be as loud as the others, and you should hear an even rhythm.

You can hear many changes long before they can be seen. A softer sound will be heard when your horse isn’t putting full weight on a leg, and the sound that follows will often be louder. If the rhythm — that is, the interval between footfalls — has a “skip” in it, with a loud ground contact following quickly after a softer sounding one, that’s your horse hopping off a sore leg more quickly and shifting weight to another leg.

Feel for tension or rigidity in your horse’s neck muscles. Neck pain can easily cause him to travel differently.

Lameness Check #5: Feel for Under-Saddle Clues
You can pick up important lameness clues when you’re in the saddle. Do you feel a relaxed sway at the walk or does your horse’s back feel rigid? If rigid, there’s pain somewhere.

When you post the trot, does your horse throw you evenly on both diagonals? If not, the side with the weak thrust may be hurting. Does he take both canter leads evenly? If he’s resisting a lead, suspect the hind leg on that side. Reluctance to turn to either direction suggests pain in a leg to the inside of that turn.

Lameness Check #6: Observe Your Horse’s Feet
Watch how your horse stands and whether he habitually points a front foot. Also watch for frequent weight-shifting up front.

Look at the feet themselves. When one foot hurts more than the other, it’ll often be smaller. It’s also often more prone to thrush because the horse will try to avoid putting full weight on that foot. Bearing full weight on a foot forces manure and bedding out of the foot, keeping it cleaner. A narrower heel and frog are other signs of decreased weight bearing.

The back of the pastern should be smooth and tight, not puffy. Filling or edema can be caused either by inflammation in the foot or problems with the deep flexor tendon or the ligaments that insert on the back of the pastern.

Look for both diffuse swelling and defined pockets of swelling or fluid as you travel up each leg. Also pay attention to any areas that feel warmer than the rest of the leg and warmer than the same area on the opposite leg.

When you pick up your horse’s legs for routine tasks, such as cleaning hooves, pay attention to whether he objects to lifting a particular leg for you. How well your horse stands for the farrier is an even better test of the same thing. When a horse doesn’t want to pick up a leg, it’s often because either the opposite one hurts to stand on, or the one you’re asking for hurts when you flex a joint.

It’s been my observation over the last 20 years or so that a lot of horse owners request to have their horses’ hocks injected whenever a hind leg problem is suspected to be impacting performance. With some horses this procedure is very productive, but I think a more open mind relating to the source of the problem is in order.

The stifle joint, which is analogous to our knee joint, is a complex and challenging joint to evaluate. Its location and size has made it a deep, dark structure to analyze. Subtle distentions or thickening of the joint capsule are not nearly so evident as the joints of the more distal limb such as the hock and fetlock. The stifle is difficult to evaluate radiographically because of its mass, surrounding tissue and critical soft-tissue structures. Flexion of the hind leg has been historically referred to as a “spavin test” denoting a problem of the hock, but horses with stifle problems certainly can be positive to this test.

So, how does one go about evaluating the stifle? I believe it takes a series of diagnostic approaches. Careful palpation of the anterior, more accessible part of the joint can reveal suspicious thickening or distention of the joint. Diagnostic blocking of the joint by injecting local anesthetics can identify it as the source of pain. Studying the soft tissue structures such as the cruciate ligaments and menisci with ultrasound imaging can be helpful.

Advanced radiographic techniques can show things such as bone remodeling, osteochondral chips or bone cysts. The ultimate diagnostic procedure sometimes resorted to is arthroscopic visualization of the joint interior. Many of these procedures are specialized and require expensive technological aids to achieve, but are essential if you are to make an accurate diagnosis. Without an accurate diagnosis, any attempt at treatment is arbitrary and less likely to succeed.

The stifle is a common source of lameness in Western performance horse endeavors such as roping, cutting, reining and barrel racing.

I think the stresses of making sharp turns while “getting in the ground” generate a lot of torque that can be damaging. These horses are the football players of the equine world, and we’re all aware of how many football players have stifle problems.