As a veterinarian, I don't get the chance often to take x-rays of 'normal' feet. Every time that I do take films of a horse, especially the feet, I take time to review them with the owner, pointing out structures so that they can understand what is going on inside and how this impacts things on the outside. Often feet are trimmed too small, too short, have under run heels or very thin soles; which then contributes to the performance and well being of that animal.
Anatomy is important and I think every horse owner should understand what is going on internally. Given this, let's look at a couple of 'normal' or actually as close to normal as I can find in my data bank and review some structures. In order to know abnormal, we must first know normal. This holds true for everything. The second thing to remember is that no horse is perfect in conformation or anatomy. If they are not perfect, we need to resist the temptation to make them perfect by trimming or shoeing. It is when we strive for perfection that we create problems, especially lameness.
Normal Foot Anatomy
Not So Normal Hoof Anatomy
So, as I mentioned, sometimes things look good on the outside but when x-rays are taken, we get a whole new picture of what is really happening. Take for instance this photo
Here is another photo of a more severe case of club footed in a youngster.
There are so many changes that can be detected when x-rays are taken. So much information can be gathered. Let's take a look at couple x-rays of more abnormal foot pathologies.
In the case the right, we have a very upright bony column or pastern angle when compared to the front of the hoof wall. On x-ray, we have evident rotation in the amount of 11 degrees. The solar angle is too steep as well but the sole thickness is actually really good and is helpful in this case in terms of aiding in he realignment of the anatomy during trimming.
The foot of the horse is a very interesting topic to me and I love to explore with x-rays to really get a good idea of what is going on. Sometimes, we will be presented a horse for a pre-purchase examination with evidently good looking feet and soundness, but discover many problems when we look inside. I don't feel that there is a specific angle for each and every horse, many do, but I do not. I do believe that it is important to try to keep angles as close to one another as possible, but we have to accept deviations from the normal, especially in cases of a horse being club footed. I feel that in many of these cases, we try to trim that poorly angled foot to match the more normal one and in the process, we create more problems due to shifting of anatomy that was not meant to be shifted or stressed. I also feel that it is important to monitor sole thickness as one of the biggest problems we encounter is thin soles due to genetics, poor nutrition or just over zealous use of the rasp. We have to understand that once a problem is created, it can take months if not years to correct that due to slow hoof regrowth. It is always best to air on the side of caution and snap an x-ray if there is any question before removing hoof or sole tissue.
I hope you find all of this useful! There is much to discover and no two horses are exactly the same.
All my best,
Tom Schell, D.V.M.
Nouvelle Research, Inc.