Annotated illustration of horse's hoof

Founder is a nautical term meaning sink, so when the coffin bone rotates or sinks inside the hoof capsule, when the hoof bone bond fails, founder is a sequela (result) of severe laminitis.
© 2020 by JoAnne Rissanen New window.

Laminitis is an inflammation (swelling) of the sensitive laminae of the horse’s foot. The sensitive laminae are normally bonded or interlocked with the horny laminae of the hoof to support the horse’s weight on the hoof wall. Founder is a nautical term meaning sink. The coffin bone rotates or sinks inside the hoof capsule when the hoof bone bond fails. Founder is a sequela (result) of severe laminitis.

The swelling or edema of laminitis is caused by a leaking of serum from the foot blood vessels. The edema is trapped between the hoof wall and bone compressing the vessels and nerves creating intense pain. Eventually the reduced blood flow caused by the edema or by the shunting of blood by arteriovenous anastamoses (valves between arteries and veins) causes the laminar tissues to die.

The hoof bone bond then fails and the bone rotates or sinks within the hoof capsule due to interstitial (between cells) fluid pressure and the weight of the horse. The blood supply of the sole is compromised by the sinking bone causing a dropped sole. The bone may even penetrate the sole. In addition, the entire system of the horse is affected.

Horses that are treated conscientiously and regularly have a chance of completely recovering. Yet, it may take several months or even a year for a severely affected horse to show improvement. A horse with a large healthy frog, a strong will to survive, the ability to tolerate pain, and that receives regular care, has the best chance of recovery. Attention to routine nursing care by the owner is usually the most significant factor in influencing an afflicted animal’s recovery rate. Rates vary according to individual case severity and quality of care.

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