Once you've determined the grade of laminitic insult, you're now ready to read and evaluate the weekly radiographs to be sure
the feet are repairing themselves. The sole depth under the distal margin of the P3 should grow 1 mm a week. If this isn't
happening, it should raise a red flag that the laminitis grade may worsen. The horn-lamellar zone should start to look normal
as it grows down from the coronary band. The measurement from the wings of P3 to the bulbar tissue should remain constant.
If this measurement becomes less (e.g., 40 mm instead of the original 45 mm), you may have a case of fatal sinker syndrome
in which the digital column starts as a rotational laminitic case and then drops distally and in a palmar-plantar fashion.
These changes require immediate attention.
Another important point: Many laminitic horses start out with negative palmar angle syndrome (NPAS). Historical radiographs
taken every year as part of the animal's wellness program will give you a leg up on knowing how bad the laminitic insult is.
Many NPAS horses in excruciating pain will appear to have a normal palmar angle, but in reality P3 has rotated radically to
Andrea E. Floyd, DVM, has specialized in equine podiatry for more than 25 years. She is the owner of Serenity Equine, Evington, Va., and the author
of Equine Podiatry. Dr. Floyd is a member of the American Veterinary Medical Association, American Association of Equine Practitioners and the
American Farriers Association.
1. Floyd AE, Mansmann RA. Equine podiatry. St. Louis, Mo: Saunders-Elsevier, 2007;323.