What is navicular disease?

• A. Disabling condition of the navicular bone and deep digital flexor tendon, primarily in the front feet; it is a chronic condition
• B. Inflammation of the coffin bone
• C. A bone spur in the hock
• D. A degenerative muscle disease

Answer: (A)

Navicular disease is a chronic, disabling condition of the horse’s navicular apparatus, primarily in the front feet, involving the navicular bone and the deep digital flexor tendon. It’s a multifactorial, degenerative syndrome that can affect how the deep flexor tendon works as it passes over the navicular region, often with irritation of surrounding structures. This explains the persistent heel- and paw-behavior lameness seen in affected horses and why it tends to be long-lasting and challenging to resolve.

The other options describe different conditions: an inflammation of the coffin bone refers to inflammatory processes within the distal phalanx itself, which is not the same as navicular apparatus involvement; a bone spur in the hock is a different joint issue located in the tarsal region; and a degenerative muscle disease is unrelated to the navicular apparatus.