Splints are a common condition in horses that affect the interosseous ligament and adjacent bone structures on the inside of the cannon bones, typically between the splint and cannon bone. While they often appear as firm, palpable bumps along the splint bone, the underlying causes and implications can vary widely — from minor training strain to more significant mechanical stress.
Because splints can develop gradually and sometimes without obvious lameness, many horse owners first notice them visually or through changes in performance rather than outright pain. Accurate diagnosis and appropriate treatment are essential not only to manage the immediate swelling but also to prevent long‑term discomfort or compensatory issues elsewhere in the limb.
This guide explains how splints are diagnosed, what signs and symptoms to watch for, and the most effective approaches for treatment and ongoing management — helping you support your horse through recovery with confidence and clarity.
✔ Repair when something goes wrong.
✔ Prevent problems before they occur.
✔ Perfect their daily routines.
What is a Splint Injury on a Horse?
A splint in a horse is a hard swelling or growth that typically appears along the inner (and occasionally outer) part of the lower leg, located between the knee or hock and the fetlock. This condition arises due to injury or strain affecting the splint bones or the ligament that links the splint bone to the cannon bone.
A horse or pony with a splint injury is likely to be in pain and will often lead to them showing signs of significant lameness. The most common age to develop Splint issues is in 2 year old training horses.
Understanding splints and how to diagnose them is an important part of caring for your horse.
Many owners will routinely carry out an inspection of their horses legs prior to each ride, looking for any heat, swelling or any rigid bumps in the splint area of the leg and whether the horse feels any pain when touched.
In this article we look at what the splint bone is, how best to diagnose if your horse has developed a splint injury and what you can do to treat the injury if it does occur.
Where is the Splint On A Horse?
On each side of a horses cannon bone are two small bones known as the splint bones. These two bones - the medial and lateral splint bones - are in fact the remains of the horses prehistoric ancestor which had multiple toes and these splint bones are thought to be remains of the second and the fourth toes.
Between the cannon bone and these two small splint bones is a ligament, known as the interosseous ligament.
As a horse gets older (normally between the age of 3 to 5) the ligament and two bones ossify and become one. Because of this, splint injuries are more commonly found in younger horses between the ages of 2 and 5.
During the ossification process a young horse may sometimes experience inflammation and swelling within the ligament itself which can lead to them experiencing pain and be further irritated by jumping, running or working the horse. Lameness created by splints at this age is most obvious in trot and will often come and go.
As the ossification process ends and the ligaments and bones fuse together injuries are less common and rarely occur in horses over the age of 5.
Splint injuries are often found in the front legs and are rarely seen in hind legs.
The majority of splint injuries occur on the medial side (inside) of the forelimbs as the medial splint bone on the inside of the leg has a flat surface and when weight is transferred to the bones the medial splint bone bears more weight that the slanted surface of the lateral splint bone.
FUN FACT: The earliest known ancestor of the modern day horse is known as a Eohippus or “Dawn Horse” which became extinct at the same time as the dinosaur.
What Causes a Splint Injury?
An injury to a splint, often referred to as “popping as splint”, occurs when the interosseous ligament is damaged. Injuring this ligament will result in inflammation and pain and an increase in heat within the area.
As well as through a direct trauma or injury a horse with poor conformation, unbalanced hooves, a mineral imbalance in their diet, being overweight or repeated work on hard and uneven ground can also lead to splint injuries and complications.
‘False splints’ are also common and are a direct result of an external trauma to the splint bones themselves, often through a kick or fall which then leads to inflammation of the splint bone itself. This can also lead to fractures in the splint bones.
Diagnosing a Horses Splint Injury
Thermal Imaging is a useful diagnosis tool when a horse has developed a splint injury. As the injury will show an increase in heat, using thermal imaging technology can show exactly where the issue has occurred providing the best opportunity to support the healing process.
Sometimes this is referred as a "popped splint".
Traditionally your vet may look towards an x-ray being done if they suspect a fracture has occurred. If your horse has an open wound or visible bruising from a kick then a fractured splint should be suspected and diagnosed prior to any treatment program is designed. Ultrasounds can also be useful to detect the specific injury to the ligament itself.
Once a professional diagnosis has been done a rehabilitation and recovery plan will be required alongside a period of box rest.
Treating Splint Injuries in Horses
In the majority of splint injuries horses will respond to a period of rest and recuperation, often with a bout of anti-inflammatory treatment to assist in the reduction of inflammation within the ligament or bone itself.
Professional diagnosis and involvement from your vet will be required, so a splint injury is likely to be expensive to treat but is also likely to be covered under your pet insurance plan.
NSAID anti-inflammatory medications (such as Bute) are widely used immediately after the injury occurs, however, with owners and vets now well aware of the long term side effects and complications created by NSAIDs many owners look towards more long term and natural forms of therapy.
Your vet may recommend a topical anti-inflammatory cream which is rubbed into the effected area, applying cold therapy such as coolboots or ice therapy to help speed-up the recovery process.
Key to 'stage one’ of the rehabilitation is reducing the inflammation and ensuring the horse is rested and not bearing too much weight on the effected leg. In most cases the heat within the splint will reduce with a few weeks.
Hydrotherapy can be a useful form of complementary treatment to support the horses recovery process along with regular compression bandaging of the affected area.
Fractures to the splint bones are generally more serious and can sometimes require an operation, particularly if the fracture occurs towards the top end of the splint bone. Plates and pins can be used in some cases to stabilise the fractured bone but fractures to the middle of the splint bone are commonly uncomplicated and will generally resolve themselves with a period of rest and rehabilitation.
The length of rest and rehabilitation required depends on the individual case and the main complication is often the amount of time required which can take months and even longer in older horses. A sports horse whether taking part in barrel racing, showjumping, eventing or polo will not be able to compete until the splint is completely healed. In the majority of cases a period of rest between 10 and 12 weeks will be required.
Once the splint has healed and the horse can return to work it is crucial that you keep an eye on the injury and go slow with the horse; rushing it back too soon could create further complications.
Magnetic Horse Boots For Horses with Splints
In 2019 a revolutionary approach to the magnetic therapy industry was released; creating significant advantages over more traditional magnetic devices and introducing a new option to horse owners who were looking to support a 'popped splint' or 'injured splint'.
EQU StreamZ Horse bands introduce bio-resonance therapy; a series of magnetic fields which unlike traditional neodymium magnets lead to no increase in heat within the horses leg. This signifies a significant advancement over using traditional magnetic products which heat up the leg and create an environment not ideal for splint injuries.
Conclusion
Continuous inspection of your horses legs is a great way to protect your horse from a splint injury. Prevention is as important as cure and detecting lameness early may help to avoid splint injuries.
If your older horse (over the age of 5) develops splints this can result in higher levels of lameness and will require extended periods of rehabilitation than with younger horses. It may also lead to arthritic issues within the joint itself.
Ensuring your young horse is warmed up properly before exercise is important as well as maintaining proper foot trimming and shoeing. If your horse is active or a sports horse then using exercise or brushing boots can help prevent impact injuries and if your horse does develop signs of a splint injury contact your vet as soon as possible.
👉 Articles of interest:
If your horse is recovering from injury, read our complete guide to Rehabilitation & Recovery for Equine Injuries (Repair).
Prevention is as important as cure. With this in mind, read our guide to How to Prevent Injuries in Horses (Prevent).
To go beyond prevention and optimise long-term soundness, explore Optimising Performance in Horses (Perfect).
Frequently Asked Questions
What are splints in horses?
Splints are firm swellings that develop along the inside of a horse’s cannon bone, usually involving the interosseous ligament and adjacent splint bone. They often result from stress, trauma, or repetitive work and can indicate strain in the forelimb or hindlimb.
What causes splints in horses?
Common causes include concussive forces from hard work, uneven training surfaces, poor hoof balance, trauma from kicking or bumps, or conformational stresses. Young horses in training are particularly prone to developing splints.
How can I tell if my horse has a splint?
Signs include a palpable, firm bump along the cannon bone, heat, and sometimes mild pain. Some horses show no lameness, while others may have subtle changes in gait or reluctance to work. Veterinary examination and imaging can confirm the diagnosis.
How are splints treated in horses?
Treatment usually involves rest or reduced workload, anti-inflammatory medication, cold therapy, and controlled exercise. Severe or painful cases may require additional veterinary interventions, such as shockwave therapy or corrective shoeing.
Can splints affect a horse’s performance?
Mild splints often do not significantly impact performance once the swelling has stabilized. However, untreated or painful splints can lead to compensatory strain in other joints or limbs, which may affect gait and performance.
Can splints be prevented?
Prevention focuses on gradual training progression, proper warm-up and cool-down routines, appropriate surface management, hoof balance, and careful monitoring for early signs of stress. Early detection and proactive management are key to reducing long-term complications.
How does EQU StreamZ help with "popped splints" in horses?
EQU StreamZ magnetic bands provide a non-invasive way to support the reduction of inflammation associated with splint injuries. Our unique bio-resonance technology helps the horse's natural recovery process without the use of aggressive magnets, making it a gentle but effective choice for managing the pain and swelling of a newly formed splint.
Is it safe to use magnetic therapy on a horse with active splint inflammation?
While traditional magnetic boots can generate heat that may worsen active inflammation, EQU StreamZ bands do not create heat. This makes them ideal for use on "active" or "popping" splints where keeping the leg cool is essential. You can safely use them alongside cold-hosing or ice boots during the initial recovery phase.
Can EQU StreamZ bands be worn during box rest for splint recovery?
Absolutely. Splint recovery often requires 10–12 weeks of restricted movement or box rest. EQU StreamZ bands are designed to be worn 24/7, providing continuous support while your horse is stabled. Unlike traditional boots, they won't cause the leg to overheat or sweat, even when left on for long periods.
Can EQU StreamZ help prevent splints in young horses?
While no product can guarantee prevention, EQU StreamZ supports overall leg health and circulation. For young horses in training (who are most prone to splints), wearing the bands 24/7 can help manage the daily concussive stress on the interosseous ligament and splint bones, supporting long-term soundness as they ossify.