TOBA: Thoroughbred Owners and Breeders Association
Owner Education

Unsoundness and Blemishes: Front Legs

Illustrations courtesy of the American Youth Horse Council's Horse Industry Handbook

An unsoundness is any defect in form or function that interferes with the usefulness of the horse. A blemish is an acquired physical defect that does not interfere with the usefulness of the horse, but may diminish its value.

Some common unsoundnesses of the front leg are:

Splint - (See illustration at right.) A calcification or bony growth, usually occurring on the inside of the cannon bone or splint bone. It typically results from a tear of the interosseous ligament that binds the splint bone to the cannon bone, but can result from any inflammation of the periosteum (thin sheathing that covers the bone). They are the result of trauma, but can be caused by slipping, running, jumping or as a result of some other concussion injury such as a kick. The location of the splint will determine if one calls it an unsoundness or a blemish. Blistering, surgery and rest are all treatments. Poor nutrition and faulty conformation (over at the knees or offset knees) can be predisposing factors.

Bucked Shins - An enlargement on the front of the cannon bone between the knee and the fetlock joints. This enlargement is due to trauma to the periosteum, most often caused by concussion. Generally, the condition is confined to soreness, but if a periostitis occurs new bone growth can result that gives one the perceived look of a "bucked" shin. This injury occurs most often in young horses in heavy training.

Bowed Tendon - (See illustration at right.) An inflammation and enlargement of the flexor tendon at the back of the front cannon bone. The general cause is severe strain. Back at the knees, long, weak pasterns, a long toe and low heel and improper shoeing are all predisposing causes. The bowed appearance is due to the formation of fibrinous tissue. Bows are classified as low, medium or high depending on location. Treatment usually requires long periods of rest. The use of enzyme injections, laser and surgical procedures are all currently being used to try and treat this injury.

Osselet - An inflammation of the periosteum on the anterior surface of the fetlock joint leading to bony outgrowths. Any conformational faults such as upright or straight pasterns that increase concussion contribute to this condition.

Sesamoiditis - An inflammation of the proximal sesamoid bones that usually results in chronic lameness. The initial cause is trauma and strain to the fetlock and injury to the sesamoid bones. A tear in the suspensory ligament can also lead to this condition.

Wind Puffs - Puffy, soft fluid-filled swellings that occur around a joint capsule, tendon sheath or bursa. They are the result of excess synovial fluid and can be found above the knee but usually are on the fetlock and pastern as a result of trauma. Wind puffs rarely cause lameness.

Navicular Disease - Any injury of the navicular bone on the front of the foot. Faulty conformation and injuries are the main causes of this condition. A straight pastern and shoulder or a small foot will increase the concussion on the navicular bone, thus forcing it against the flexor tendon causing excess friction and damage to the bursa sac. Horses with this condition have a shortened stride and tend to go up on their toes with an increased tendency to stumble. A resting and standing horse may "point" the affected toe. Corrective shoeing with a short toe and elevated heel helps, but there is no cure.

Carpitis or Popped Knee - Any enlargement of the knee joint as a result of inflammation to the joint capsule, the bones of the carpus (knee) or the associative ligaments. Faulty conformation such as back at the knees or offset knees contributes to this condition.

Epiphysitis - An inflammation of the epiphyseal cartilage plate (growth plate) of the long bones. It most often affects the front legs as a result of trauma, infection or nutrition. It is a condition that affects young, growing horses.

Capped Elbow or Shoe Boil - A bursitis or swelling at the point of the elbow that is usually caused by irritation to the elbow bursa with the shoe or hoof of the front foot when lying down. It is most commonly found in stabled horses or horses that have other injuries or lameness problems.

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