Sidebone refers to the ossification (hardening into bone) of the collateral cartilages of the [coffin bone](/anatomy/coffin-bone-distal-phalanx-p3). These cartilages normally provide flexibility and shock absorption at the heels. When they ossify, they become rigid and can restrict heel movement or cause pressure on surrounding structures, sometimes leading to lameness. ## What it is The collateral cartilages are wing-like structures attached to the sides of the coffin bone. In sidebone, these cartilages gradually turn into bone, a process that is often age-related or associated with chronic concussion and poor hoof conformation. While sidebone is common in older horses and draft breeds and is frequently an incidental finding, it can become problematic when the ossification is extensive, asymmetric, or causes pressure on the [navicular bone](/anatomy/navicular-bone-distal-sesamoid-right-forelimb), digital cushion, or sensitive laminae. ## Signs and symptoms - Chronic, low-grade lameness, often worse on hard ground or circles - Heat or sensitivity over the affected heel region - Reduced heel expansion during movement - In some cases, visible or palpable bony enlargement above the coronary band at the heels - Lameness that may improve with rest but returns with work ## Causes and risk factors Sidebone is associated with repetitive concussion, poor hoof conformation (especially contracted heels or upright feet), and chronic overload. It is more common in older horses, draft breeds, and horses with a history of heavy work on hard surfaces. The condition develops gradually over time. ## How it is diagnosed Diagnosis is made with radiographs, which clearly show the ossified collateral cartilages. Clinical correlation is important because many horses with radiographic sidebone are sound. Hoof testers, nerve blocks, and sometimes MRI help determine whether the sidebone is contributing to lameness. ## Treatment and management Treatment focuses on improving hoof mechanics and reducing concussive forces. Corrective farriery to encourage heel expansion and support is the mainstay. Anti-inflammatory medication may be used during flare-ups. In rare severe cases where sidebone causes significant pressure or lameness, surgical options are occasionally considered, but most horses are managed conservatively with ongoing farriery and controlled exercise. ## When to call the vet Contact your veterinarian if your horse develops persistent lameness, especially if accompanied by heat or sensitivity in the heel region. Radiographs are needed to confirm sidebone and rule out other causes of heel pain such as [navicular syndrome](/conditions/navicular-syndrome). ## Prevention Prevention centers on maintaining good hoof conformation and balance through regular professional farriery and avoiding excessive concussion on hard surfaces. Horses with conformational risk factors benefit from proactive hoof care and conditioning on varied footing. ## Frequently asked questions **Is sidebone always painful?** No. Many horses have significant sidebone on radiographs without lameness. Pain usually occurs when ossification is extensive or causes pressure on other structures. **Can sidebone be reversed?** No. Once the cartilage has ossified into bone, the change is permanent. Management focuses on minimizing further stress and improving comfort. **Does sidebone affect shoeing?** Yes. Farriers often use shoes and trimming techniques that encourage heel expansion and reduce pressure on the ossified areas. This information is for educational purposes only. Always consult with a licensed veterinarian for diagnosis and treatment of your horse.
Chronic, low-grade lameness, often worse on hard ground or circles; heat or sensitivity over the affected heel region; reduced heel expansion during movement; in some cases, visible or palpable bony enlargement above the coronary band at the heels; lameness that may improve with rest but returns with work
Sidebone refers to the ossification (hardening into bone) of the collateral cartilages of the [coffin bone](/anatomy/coffin-bone-distal-phalanx-p3). These cartilages normally provide flexibility and shock absorption at the heels. When they ossify, they become rigid and can restrict heel movement or cause pressure on surrounding structures, sometimes leading to lameness. ## What it is The collateral cartilages are wing-like structures attached to the sides of the coffin bone. In sidebone, these cartilages gradually turn into bone, a process that is often age-related or associated with chronic concussion and poor hoof conformation. While sidebone is common in older horses and draft breeds and is frequently an incidental finding, it can become problematic when the ossification is extensive, asymmetric, or causes pressure on the [navicular bone](/anatomy/navicular-bone-distal-sesamoid-right-forelimb), digital cushion, or sensitive laminae. ## Signs and symptoms - Chronic, low-grade lameness, often worse on hard ground or circles - Heat or sensitivity over the affected heel region - Reduced heel expansion during movement - In some cases, visible or palpable bony enlargement above the coronary band at the heels - Lameness that may improve with rest but returns with work ## Causes and risk factors Sidebone is associated with repetitive concussion, poor hoof conformation (especially contracted heels or upright feet), and chronic overload. It is more common in older horses, draft breeds, and horses with a history of heavy work on hard surfaces. The condition develops gradually over time. ## How it is diagnosed Diagnosis is made with radiographs, which clearly show the ossified collateral cartilages. Clinical correlation is important because many horses with radiographic sidebone are sound. Hoof testers, nerve blocks, and sometimes MRI help determine whether the sidebone is contributing to lameness. ## Treatment and management Treatment focuses on improving hoof mechanics and reducing concussive forces. Corrective farriery to encourage heel expansion and support is the mainstay. Anti-inflammatory medication may be used during flare-ups. In rare severe cases where sidebone causes significant pressure or lameness, surgical options are occasionally considered, but most horses are managed conservatively with ongoing farriery and controlled exercise. ## When to call the vet Contact your veterinarian if your horse develops persistent lameness, especially if accompanied by heat or sensitivity in the heel region. Radiographs are needed to confirm sidebone and rule out other causes of heel pain such as [navicular syndrome](/conditions/navicular-syndrome). ## Prevention Prevention centers on maintaining good hoof conformation and balance through regular professional farriery and avoiding excessive concussion on hard surfaces. Horses with conformational risk factors benefit from proactive hoof care and conditioning on varied footing. ## Frequently asked questions **Is sidebone always painful?** No. Many horses have significant sidebone on radiographs without lameness. Pain usually occurs when ossification is extensive or causes pressure on other structures. **Can sidebone be reversed?** No. Once the cartilage has ossified into bone, the change is permanent. Management focuses on minimizing further stress and improving comfort. **Does sidebone affect shoeing?** Yes. Farriers often use shoes and trimming techniques that encourage heel expansion and reduce pressure on the ossified areas. This information is for educational purposes only. Always consult with a licensed veterinarian for diagnosis and treatment of your horse.
Chronic, low-grade lameness, often worse on hard ground or circles; heat or sensitivity over the affected heel region; reduced heel expansion during movement; in some cases, visible or palpable bony enlargement above the coronary band at the heels; lameness that may improve with rest but returns with work