Disorder characterized by new bone growth adjacent to either the pastern or coffin joints; caused by tearing of the collateral ligaments stabilizing the joint. High ringbone describes bone growth around the pastern joint, while low ringbone describes bone growth around the coffin joint.
Exostosis in or around the coffin or pastern joint, or on the pastern bones. High ringbone is in or near the pastern joint and is usually palpable. Low ringbone is in or near the coffin joint, and often is not directly visible. Articular ringbone actually involves a joint. Periarticular ringbone is located around, but not within a joint. Exostosis on the pastern bones, between the joints, is called false ringbone or non-articular ringbone.