Understanding Splints

Splints are one of the most common bony enlargements seen on the lower limb of the horse. Although many become little more than cosmetic blemishes once healed, some can cause pain and lameness, making early assessment important.

What Is a Splint?

A splint is a hard bony swelling that develops on the inside, and less commonly the outside, of the lower limb between the carpus (knee) and the fetlock. Most splints involve the splint bones and the interosseous ligament, a short, strong ligament that firmly attaches each splint bone to the cannon bone.

Types of Splints

True Splints

True splints are the most common type. They occur when the interosseous ligament becomes damaged or inflamed, leading to new bone formation. They are commonly associated with direct trauma or repetitive strain.

Blind Splints

Blind splints develop on the inner surface of the splint bones and are often less visible because they lie deeper within the limb. Despite being difficult to detect externally, they may still cause lameness, particularly if they place pressure on the suspensory ligament.

Knee Splints

Knee splints occur in or around the carpus (knee) and may result in pain, inflammation and reduced joint mobility.

Chain Splints

Chain splint is not a true anatomical classification but is commonly used to describe two or more closely associated true splints occurring together.

Clinical Presentations

Fractured Splints

Direct trauma is the most common cause of splint bone fractures.

• Lower fractures often respond well to surgical removal of the fractured section.
• Middle fractures are usually uncomplicated and commonly heal within five to seven weeks.
• Upper fractures are more complex because removing the upper splint bone can compromise the stability of the carpus. Surgical stabilisation using plates and screws may occasionally be required.

Popped Splints

Popped splints often present as a rapidly developing, warm swelling along the side of the cannon bone. Lameness is common but is not always present. The underlying injury is usually damage to the interosseous ligament, resulting in inflammation followed by new bone formation.

Quiet Splints

Quiet splints may appear with little or no heat, swelling or lameness and are often discovered incidentally. Many require no treatment or prolonged rest.

Causes

Common causes include:

· Damage to the interosseous ligament.

· Poor limb conformation.

· Overwork or inappropriate training.

· Direct trauma.

· Rapid bone growth in younger horses.

Clinical Signs

· Hard swelling along the splint bone.

· Heat and inflammation.

· Pain on palpation.

· Lameness of varying severity.

Diagnosis

Veterinary examination is recommended whenever a horse develops a new swelling on the cannon region, particularly if heat, pain or lameness are present. Radiographs may be required to determine whether the splint bone has fractured or whether surrounding structures have been affected.

Prognosis

The prognosis is generally very good, with most horses making a full recovery following appropriate rest and management.

Splints situated close to the suspensory ligament are more likely to cause persistent lameness than those positioned away from important soft tissue structures.

Occasionally, recurring splints may require changes to training, workload or long-term management.

Summary

· Splints are common bony enlargements affecting the lower limb.

· Many are cosmetic once healed, although some cause pain and lameness.

· Early veterinary assessment helps identify more serious injuries.

· Most horses recover well with appropriate treatment and management.

A Final Thought

Not every splint requires treatment, but every new splint deserves an accurate diagnosis. Early assessment allows the underlying cause to be identified and gives your horse the best opportunity for a full recovery.

About the HØØF Knowledge Hub

The HØØF Knowledge Hub exists to provide horse owners with clear, practical and evidence-based information on hoof health, lower limb conditions and farriery.

Every horse is an individual, and no online article can replace professional assessment. If you have any concerns about your horse's health or soundness, always seek advice from your veterinary surgeon or registered farrier.

Article Information

Author: Paul Conroy BSc (Hons) AWCF
Organisation: HØØF Equine Hoof Care
Category: Lower Limb Conditions
Document Reference: HKH012
First Published: July 2026
Last Reviewed: July 2026