Understanding the disease progression of abnormal hoof anatomy, Part 1
Part 1: The mathematical needs of the lower grades of laminitis
Nov 01, 2011
The lower grades of laminitis
The HLZ is the perpendicular distance between the hoof wall and the coffin bone. It is measured in two places, just below the extensor process and at the apex. The HLZ in adult light-breed horses is usually 17 to 19 mm (e.g., 17/17 mm, 18/18 mm, or 19/19 mm) (Figure 1). The more disparity between your first number and second number, the greater the laminar wedge or rotation away from your hoof wall. Note that an HLZ of greater than 20 mm in a light-breed horse represents serious edema.
The digital alignment, which is normally considered to be a straight line or 180 degrees when measured with a goniometer, will appear bent at the distal interphalangeal joint and will have a lower goniometer reading (e.g., 165 to 170 degrees). I like to measure the digital alignment from the dorsal distal face of P1 through the dorsal face of P2 and P3.
Following are some important facts to keep in mind if you are fortunate enough to see a horse in the first stages of the disease process:
Trying to figure out the mathematical needs of the foot is fun. Pull out a few old radiographs, judge the needs of those feet, and then look up your history to see what you did and how the horses responded. Grade I and II laminitis cases generally respond well to the therapy outlined here and should return to soundness, if treated properly.
Have fun with the calculations and maybe you will start enjoying these cases the way I did so many years ago.
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.