 |
Articles & Information
FROM THE HOOFCARE & LAMENESS ARCHIVES Key
Concepts of Hoof Anatomy and Function The
"toys", as we call our electronic analysis aids, seem
fundamentally ahead of their time when we realize how little we really
know about the foot. In his quest to understand the disease of
laminitis, Australian researcher Chris Pollitt had to start with the
normal foot, and learn how it functioned so he could find out what was
amiss with laminitis. The result, captured for the world on videotape
in his premier production "Equine Foot Studies", has been
discussed around the globe since it debuted at the Bluegrass Laminitis
Symposium in January. For
anyone who has not seen the videotape, it will increase your
understanding of current theory in hoof physiology better than any
number of readings will. Also recommended is Dr. Pollitt's chapter on
"The Normal Equine Foot" in Equine Lameness and Foot
Conditions. Both the video and the book are available through Hoofcare
and Lameness and many veterinary college libraries. Dr.
Pollitt's research on the normal foot shows us how and why some things
go wrong. Highlights include: .
The effect of pastern extension on the blood flow to the foot: When
the pastern is extended, no blood enters the foot; it stops at the
coronary band. When the pastern is only 50 percent extended, blood
reaches the toe by its alternate route through the dorsal branch. .
Sole pressure compromises the circumflex artery's function, so no
blood reaches the toe. This is compounded when a wide-web shoe is
applied with pressure. .
A heartbar shoe improves blood circulation to the toe; a similar
effect is achieved with a raised-heel shoe when the pastern is
extended. "A
well-conformed horse will stay sound," stated Olin Balch DVM of
the University of Saskatchewan when he lectured to the American
Farrier's Association Convention in Florida in February. Dr. Balch
surveyed the observable conditions of the exterior of the hoof
capsule, and equated the harmonious nature of "balance" with
an ideal set of exterior parameters. Balance
remains an elusive concept for definition, but Dr. Balch feels that
isolating one balance factor at a time can reveal its role in the
overall picture and that the ideal combination of external conditions
of the hoof capsule means balance for all the structures of the foot.
He showed how elevating one side of the hoof redirects force to that
side; how landing patterns vary between the walk, trot, and canter;
and how the normal foot prefers weight transfer up the medial aspect
of the leg. David
Duckett FWCF on the other hand, is lecturing around America from the
converse point of view. Duckett sees the external factors as
indicators of the balance of the center. He begins there and works
out, while Balch implies that the center will work if the externals
are balanced. Duckett's dot theory, along with Scott Simpson's "Eagle Eye" foot visualization theory, have changed the way that many farriers look at the foot. Certainly, Mr. Duckett didn't invent the center of the foot, nor did Simpson invent the perimeter of hoof wall, but by putting clever names to foot structures and characteristics, they have made people look at feet differently. And remember those theories every time they pick up a foot. "It's
just a reference point, but it never changes," said Duckett in a
recent talk. "What other point on the foot never changes, never
moves?" We can look at the shape of the foot by measuring out
from the dot, instead of around the ever-changeable perimeter.
Duckett's work is part anatomy and physiology, part psychology. Dr.
Larry Bramlage, on the other hand, said that he felt that proper
balance and limb position were neurologic functions. He asked farriers
at the AFA Convention to remember that, at full speed, it is the check
ligament system that carriers a horse's weight. "The lower limb
is like a suspension bridge," he said. "Think of the cables
on a crane." This article originally appeared in Hoofcare & Lameness: The Journal of Equine Foot Science and is available for your personal use only. Re-publication is prohibited without the express written permission of Hoofcare & Lameness. Detailed information on this and many other hoofcare topics can be found in Hoofcare & Lameness publisher Fran Jurga's award-winning guide to hoofcare, "Understanding the Equine Foot". For more information, or to order, click here Back to the articles table of contents
Write to H&L: PO Box 6600, Gloucester, MA 01930. Tel 978 281 3222; fax 978 283 8775. Email webinquiry@hoofcare.com. Internet http://www.hoofcare.com. © 1998
Hoofcare & Lameness |