What is nevicular?

Answer 1

Navicular Disease is a soundness problem in horses, more accurately called "navicular syndrome" as opposed to "disease." It most commonly describes an inflammation or degeneration of the navicular bone and its surrounding tissues, usually on the front feet. It can lead to significant and even disabling lameness.

http://en.wikipedia.org/wiki/Navicular_disease

Answer 2

It appears there is a typo in your question. It is likely you are referring to the "navicular" bone which is a small bone in the foot, specifically in the arch area. The navicular bone helps support the arch and plays a role in balance and stability during walking and running.