By Garrett Metcalf, DVM
The nomenclature surrounding navicular conditions in horses has undergone changes over the past 10 years with the advent of new diagnostic tools to further explore the causes of lameness that encompasses the navicular bone in horses. The current terminology shifts the sole blame of the cause of lameness in horses away from the navicular bone to include the surrounding soft tissues the make up of the podotrochlear apparatus in the feet of horses. Hence, calling horses diagnosed with navicular conditions, navicular syndrome or caudal heel pain, rather than navicular disease, which implies the primary structure that is the cause of the lameness is the navicular bone itself.
Regardless of the terminology to describe these navicular issues, navicular syndrome is still a major player in causing forelimb lameness in many horse breeds and disciplines. Horses with lameness due to navicular syndrome commonly have a short-strided, choppy gate, often land toe-heel rather than heel-toe and majority worsen when trotted in circles towards the lame limb.
These horses often have pain response to hoof testers across the heels of the foot and often present with podiatry issues that are not being addressed properly. The onset of lameness can be slow, insidious onset or acute sudden lameness after a specific event, either while in work or in turn out. The typical approach to examine a horse for forelimb lameness suspected of having navicular syndrome is fairly straight forward. A complete history is often gathered from the owner or trainer who is riding the horse.
A physical exam is then performed including palpation of the limb, examination of the feet and hoof testers are used to complete the hoof exam. The horse is then trotted in-hand through a lameness pattern including straight lines and circles both directions. Flexion tests are also part of the examination process to gather more information and isolate areas of the limb that are causing the pain.
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