Reading Radiographs

QUESTION: 

What guidelines do you follow in interpreting radiographs of the hoof?
I've heard about the angle formed by the bottom of the coffin bone (P3) and a
line parallel to the ground (should be 3-5 degrees in front and 5-8
behind) or alternatively, the line formed by the line central to P1, P2 and P3
should be straight not broken forward or back. These could have different
results. Or is there yet another way of viewing these? I've heard that
having radiographs is the only real way to know what is happening inside
the hoof, to give guidelines on trimming etc.

Thanks for your time.
Nancy M

DR. TOM'S ANSWER:

We have heard an abundance of information in years past about the "ground
parallel" coffin bone and how it must be placed this way to be in the
healthiest position. As much as this idea has permeated throughout the
horse world, it is becoming pretty clear that we are going to have to
re-assess what is going on, and that we may be better served with a hoof
form that results in a "relatively ground parallel" coffin bone rather than
a perfectly ground parallel one. That's all I'll say on that right now.

With that in mind, I can tell you that I do not put near the effort in to
studying radiographs of horse's feet as I used to. Rather, I combine what
I'm seeing with the landmarks on the hoof capsule and the way the horse
stands and moves. I can tell you where the coffin bone physically is by
looking at a hoof capsule, but I can't tell you accurately what condition it
is in...this is what I generally use radiographs for any more. Of course
one can also assess joints and joint spaces, bone density and check for any
number of bone diseases using radiographs. Sole thickness can be assessed
by looking at the films, but one can also know sole thickness without x-rays
with enough experience.

I trim horse's feet by looking at what the capsule is "saying"...where can
exfoliation occur today? How much heel can come off of this horse today?
Where can this toe be placed today? Remember the entire coffin bone and
lateral cartilages are covered with corium, and the corium makes the hoof
capsule. By looking at the hoof capsule carefully you can tell where the
coffin bone is and what it is doing, where it is stressed, where it is
starved for blood, where it is abcessing...on and on. So, anyone who
believes that they must have x-rays in order to tell what is going on inside
a hoof and to trim that horse's hoof is not paying attention to what the
hoof is saying. Also, radiographs only show us dense tissues like
bone...the soft tissues, which make up at least 50% of the horse's hoof, are
not able to be assessed very well at all, so we need to keep that in mind
before we put a lot of extra faith in information from radiographs of the
feet. I think we will see a change in our thinking about what we can and
can't say about the horse's feet by looking at radiographs. Perhaps MRI
and/or CT type technology will be able to better image the horse's feet
before long?

Also, with respect to HPA (hoof pastern axis), we put way too much effort in
to trying to "align" this or worry that it isn't quite right. What matters
to the horses is to have properly shaped hooves! Bring the hooves in to a
better form and the entire rest of the horse's skeleton comes in to a
harmonic balance. It all starts with the feet on the ground! And it makes
sense, doesn't it? The feet are there for protection, locomotion,
sensation...after countless numbers of horses it's very clear that what is
most important is a good "base". Horses use their FEET to engage their
environment every step of their lives. I look at dozens of lame horses
every month and over 85% of them have FEET that are deformed, poor
functioning, shod, trimmed horribly, neglected or just left out of the
equation. It's more than just a situation of "no hoof, ho horse". We're
talking about giving horses their LIVES back. Good hoof care is so vitally
important to horses' overall health that we will continue to see
"miraculous" recoveries from other ailments simply by tending to their feet.

Keep reading, keep learning and keep looking at horse's feet and listen to
what they are saying. If something makes sense to you and it "fits" with
what you know about the NATURE of the horse, dig deeper and discover even
more.

All this from a simple question about x-rays...ahh, well, I just got a
little excited.