The navicular bone is small and somewhat boat shaped— in fact, the literal translation from Latin and French means "little ship." Stumbling is a nuisance factor in navicular disease. In advanced cases, adhesions between the navicular bone and deep flexor tendon restrict normal extension of the toe and contribute further to the stumbling problem. Navicular disease is diagnosed by a combination of appropriate history, clinical signs, response to "heel blocks," and x-ray findings. The first treatment attempted should be corrective shoeing. Horses with average heels are usually shod with another type of bar shoe and rolled toe. The bar is placed under the middle of the frog, directly below the navicular bone to protect it. Nerving is a surgical procedure whereby the palmar digital nerves are cut and a length of nerve removed, which numbs the entire heel area including the navicular bone.