Horse Lameness: How to Spot It and What Causes It

The Problem That Costs More Than Anything Else

In more than two decades of equine practice, I have answered more calls about lameness than any other complaint. Not colic, not wounds, not respiratory disease — lameness. It is the single most common reason horse owners pick up the phone, the leading cause of lost performance in every discipline, and the number one reason horses are retired before their time.

And here is what frustrates me: by the time most owners call, the lameness has been present for weeks, sometimes months. Not because they do not care — because they did not see it. Lameness in horses can be extraordinarily subtle, and the untrained eye misses what a careful observer would catch. My goal with this article is to give you the tools to see what your horse is telling you before a minor issue becomes a major one.

The Head Bob Rule: Your Most Important Diagnostic Tool

If you learn one thing from this article, let it be this: you can identify which leg is lame by watching the horse's head. This works for forelimb lameness and it is remarkably reliable.

When a horse has a painful front leg, it will try to unload that leg as quickly as possible during the weight-bearing phase of the stride. To do this, the horse shifts its center of gravity away from the painful leg — and the head acts as the counterweight. Watch the horse trot in a straight line on a firm, flat surface. The head will bob up when the lame leg hits the ground and drop down when the sound leg hits. The horse is literally lifting its front end off the painful leg.

The mnemonic I teach every vet student: "Down on sound." The head drops on the sound (good) leg. The head rises on the lame (bad) leg.

Hind limb lameness is harder to see from the head, but it has its own signature. Watch the horse's pelvis (hips) from behind as it trots away from you. The hip on the lame side will hike up (the horse lifts that hindquarter to unload the painful leg), or alternatively, the hip on the sound side will drop lower than normal. Some clinicians describe it as the hip "dropping" on the sound side. The pelvis will look asymmetric — one side moving more than the other.

Both of these observations require the horse to trot. Walk is too slow to see the asymmetry. Canter masks it because the footfall pattern is different. The trot is the diagnostic gait. Have someone lead the horse at a brisk trot on hard, flat ground in a straight line while you watch from the front (for forelimb) and behind (for hind limb). Ten strides is usually enough to see it.

The AAEP Lameness Scale

The American Association of Equine Practitioners uses a standardized 0-to-5 grading scale that helps veterinarians communicate about lameness severity. Understanding it will help you describe what you are seeing to your vet over the phone.

• Grade 0: Sound. No detectable lameness under any circumstances.
• Grade 1: Difficult to observe. Not consistently present regardless of circumstances (straight line, circles, inclines, hard/soft ground). This is the horse that "sometimes looks a little off" but you cannot pin it down.
• Grade 2: Difficult to observe at a walk or trot in a straight line, but consistently apparent under certain circumstances — typically lunging on a circle, on hard ground, or after flexion. This is where many chronic, low-grade lamenesses live.
• Grade 3: Consistently observable at a trot under all circumstances. This is the horse that is clearly "off" — anyone watching can see the head bob or hip hike.
• Grade 4: Obvious lameness with marked head bob, shortened stride, or altered gait. The horse is clearly uncomfortable and may resist trotting.
• Grade 5: Non-weight-bearing. The horse cannot or will not put the affected limb on the ground. This is the three-legged-lame horse and it is always an emergency call.

Where Lameness Comes From: The Common Causes

Here is a statistic that reshapes how you think about lameness: approximately 95 percent of forelimb lameness in horses originates below the knee. That means when your horse is lame in front, the problem is almost certainly in the hoof, pastern, or fetlock — not the shoulder, not the elbow, and not the upper leg. The foot is the answer to most lameness questions.

The Hoof: Where Most Lameness Lives

Hoof abscess: If I had to name the single most dramatic yet least serious lameness I encounter, it is the hoof abscess. The story is always the same: the horse was fine yesterday, today he is three-legged lame, and the owner is terrified it is a fracture. An abscess is a pocket of infection (pus) trapped between the hard hoof wall and the sensitive laminae inside. The pressure is excruciating because the rigid hoof capsule does not allow swelling. But once the abscess finds its way out — either through the sole, the coronary band, or with veterinary help — the relief is immediate and the prognosis is excellent. Most abscesses resolve within a week.

Navicular syndrome: This is a chronic, progressive condition involving the navicular bone and its associated structures (the deep digital flexor tendon, the navicular bursa, and the distal sesamoidean impar ligament) in the back of the foot. Navicular horses are typically bilaterally affected (both front feet), land toe-first instead of heel-first, and have a shortened, choppy stride. The lameness worsens on hard ground and on circles. This is a condition that requires veterinary workup with nerve blocks and imaging (radiographs and possibly MRI).

Sole bruise: Exactly what it sounds like — a bruise on the bottom of the foot, usually from stepping on a rock or hard surface. The horse will be tender on that foot, especially on hard ground. Hoof testers (giant pliers that your vet squeezes across different parts of the sole) will localize the pain. Rest, pads, and time resolve most sole bruises.

Laminitis: Inflammation and damage to the laminae — the interlocking tissue that suspends the coffin bone inside the hoof capsule. Laminitis is a medical emergency. The horse assumes a classic "leaning back" posture (weight on the heels, rocked backward to unload the toe) and is painful on both front feet. The digital pulses will be bounding (you can feel a strong pulse at the back of the pastern). Laminitis can cause permanent structural damage, including rotation and sinking of the coffin bone. Call your vet immediately.

The Fetlock and Pastern

Suspensory ligament injuries: The suspensory ligament runs down the back of the cannon bone and branches at the fetlock. Tears or strains cause lameness that is often worse on soft footing and on a circle with the affected leg on the inside. Diagnosis requires ultrasound.

Sesamoiditis: Inflammation of the proximal sesamoid bones at the back of the fetlock. Common in racehorses and sport horses. Presents as fetlock pain, swelling, and lameness after work.

Upper Limb

Arthritis (osteoarthritis/degenerative joint disease): Affects any joint but commonly the hocks, stifles, coffin joints, and pastern joints. Lameness is typically worse after rest (the horse "warms out of it") and worse after heavy work. Joint effusion (swelling) may be visible. Management includes joint injections, systemic joint support, controlled exercise, and NSAIDs.

OCD (osteochondritis dissecans): A developmental condition where a flap of cartilage and underlying bone separates within a joint. Most commonly seen in young horses (yearlings and two-year-olds) in the hocks, stifles, and fetlocks. Surgical removal of the fragment is curative in most cases.

The Owner Lameness Exam: What You Can Do at Home

Before you call me, there are a few things you can do to gather information that will help me help your horse more efficiently.

The Straight-Line Trot

Have someone lead the horse at a brisk trot on a firm, level surface (a driveway or paved barn aisle works well). Watch from the front for forelimb lameness (head bob) and from behind for hind limb lameness (hip asymmetry). If you can, video this on your phone. A 30-second video is worth ten minutes of verbal description.

The Lunge Test

If the horse looks sound in a straight line, lunge at a trot on both reins on a 10- to 15-meter circle. Many lamenesses become apparent on a circle that are hidden in a straight line. The lame leg will be more obviously affected when it is on the inside of the circle (the inside leg bears more load). Note which direction is worse.

The Flexion Test

Pick up the foot and flex the joint firmly for 60 seconds, then release and immediately trot the horse away. A positive flexion test — the horse is noticeably more lame for the first few strides after flexion — suggests pain in the flexed joint. This is not a definitive diagnosis (flexion tests have high sensitivity but low specificity, meaning they catch a lot of problems but do not tell you exactly what the problem is), but it helps localize the region.

Check for Heat, Swelling, and Digital Pulse

Run your hands down all four legs and compare. Feel for heat, swelling, or thickening over tendons and joints. Check the digital pulse at the back of the pastern (place your fingers in the groove between the flexor tendons and the sesamoid bones). A bounding digital pulse suggests inflammation in the foot — laminitis, abscess, or bruise.

When to Call the Vet vs. When to Wait

This is the question I get most often, and the answer depends on the severity and the context.

Call Now — Today

• Non-weight-bearing lameness (Grade 5): The horse cannot put the leg down. This could be a fracture, a severe soft tissue injury, or a foot abscess. Until I examine the horse, we treat it as serious.
• Sudden severe lameness with swelling: Especially in a tendon or ligament area. Acute soft tissue injuries benefit from immediate icing and anti-inflammatory treatment.
• Bilateral forelimb lameness with bounding digital pulses: This is laminitis until proven otherwise. Time matters — the faster we initiate treatment, the better the outcome.
• Lameness after a known trauma: Kick from another horse, caught in a fence, stumbled badly. Rule out fracture first.
• Lameness with a wound: Any wound near a joint or tendon sheath that is accompanied by lameness is a potential synovial (joint) infection, which is a life-threatening emergency.

Schedule an Appointment This Week

• Consistent Grade 2-3 lameness: The horse is clearly off but not in acute distress. Get it evaluated before it worsens.
• Lameness that worsens over several days: This suggests a progressive process that needs diagnosis.
• Post-exercise lameness that does not resolve with 48 hours of rest: Minor strains resolve quickly. If it is still there after two days of rest, something is going on.

Monitor and Record

• Intermittent, mild lameness (Grade 1): The horse that is "sometimes a little off" but you cannot reproduce it consistently. Video every episode. Note the conditions — footing, temperature, after work vs. first thing in the morning. Bring the videos to your next vet visit.
• Lameness that resolves completely within 24 hours: May have been a stone bruise or a minor misstep. Monitor for recurrence.

Investing in Soundness

Every experienced horse person eventually learns the same lesson: a horse's career — and its quality of life — depends on keeping it sound. That means regular farrier work, appropriate footing, sensible conditioning, prompt attention to lameness, and the discipline to stop riding and call the vet when something is wrong instead of hoping it will resolve on its own. I have treated hundreds of lamenesses that would have been simple if they had been caught early and were complicated only because the owner waited. Your horse does not have words, but it has a gait. Learn to read it.