Proper conformation in the horse is vital to athletic performance, but it doesn’t always have to be a limiting factor. In my years of practicing veterinary medicine and performing pre-purchase examinations, I have yet to encounter a ‘perfect’ horse in terms of conformation by book definition. Every horse is an individual with conformation often based on genetics passed on from dam or sire. We have to accept things for the way they are, understand that there will be some limitations but also that certain flaws will predispose more to injuries. We can try to minimize these occurrences, but an understanding as to why they happen is important.
I have discussed some basic conformational flaws in the pastern and hoof in the past, but today, I’d like to focus more on the front and rear limbs for a general discussion, which directly impact gait and path of travel. Each breed is different, with a different body type, build and conformational flaws. Let’s look at the front limbs for starters:
When we evaluate the limbs from the front, ideally a plumb line drawn and dropped from the point of the shoulder bisects the limb through the carpus, cannon bone region, fetlock and hoof; essentially splitting the limb into two equal halves. From the side view, a plumb line dropped from the spinous process of the scapula bisects the limb down through the carpus, cannon bone and fetlock to the ground. The chest should be full overall, well muscled, and the limbs are as far apart on the ground surface as they are from their origin on the chest.
Ideally, when viewed from the side, a plumb line dropped from the point of the tuber ischii follows or contacts the point of the hock with the metatarsus then following below. When viewed from behind, a plumb line dropped from the tuber ischii should bisect the rear limb through the hock, metatarsal region and fetlock. The hindquarters should be well muscled with the limbs as far apart on the ground as they are from their origin point.
Let’s start with a 4 y.o. OTTB gelding that we recently acquired. In the photo contained below, we have him from a head on shot of the front limbs. If you drop the plumb line (red line) from the point of the shoulder, one can obviously note that he is what is termed ‘base narrow’. In addition to this, he is also perceived
as being toed out in this photo. A base narrrow type of conformation is often seen with narrow chested horses and can lead to limb interference as they travel. The toed out type of conformation is also common with a base narrow frame and leads to altered type of travel termed “winging” during forward movement.
If you further evaluate this conformation by viewing the front limbs as a pliable stick, by being base narrow, we will be essentially stretching the inside joints/ligaments, while compressing the outside or lateral joints/ligaments. In basic terms, these guys are then prone to various forms of joint conditions due to improper loading of the joints and ligaments.
Now let’s look at this guy’s hindlimbs. As you can see below, if we drop that plumb line down from the point of the ischium to the ground, we do not come into contact with the point of the hock. Actually the point of the hock is forward from this line, thus we would refer to him as ‘standing under from behind’. This type of conformation can actually impair forward movement, thrust and power, plus add additional strain to various joints including the hock.
In the final photo of this OTTB gelding, we have the front limb side shot. Here we can see some pretty good conformation as the plumb line dropped from the point of the spinous process bisects the limb rather nicely through the fetlock.
Now let’s evaluate an 8 y.o. Hanoverian gelding that is currently being used as a hunter. Below we have both the front limb and rear limb photos.
Looking at the photos from left to right, we see that the rear limbs maintain pretty good conformation in relation to the plumb line. The front limb shot directly on indicate that he is slightly base narrow in relation to the red line. The side view of the front limbs indicate that he is slight under in the front. You will note in this side photo of the front limbs that he is also club footed on the RF foot and the heel is slightly off the ground in this photo due to contraction of the tendons.
Here we have a 19 y.o. Appendix QH gelding that has a history of chronic osteoarthritis of his lower hock as well as back issues. He is currently being well managed, but here we can see his conformational flaws both as a result of genetics but also secondary to the degenerative conditions that he possess. In many cases, arthritis becomes limiting in terms of joint motion and the animals will secondarily adapt to shifting weight or placement of limbs in order to move about.
As you can see in the photo to the right, he is standing under from behind, but you will also see the steep slope to the pelvis that he has acquired over time. This change in the pelvis conformation is likely due to ongoing hock arthritis, the need to shorten the stride and collect himself underneath. Obviously, with this conformation, the range of motion and forward movement of the rear limbs is going to be limited, which is evident when he is trotting about.
In the image to the left, we are able to see the front limbs head on. Here, based on the red plumb line, he is base narrow in conformation.
Here we have, for comparison sake, a 12 y.o Percheron mare. She is very camera shy by nature and thus hopefully the photos will work for our purposes. In the side view photo, we can see that she is actually standing under from behind and is slightly back in the front limbs as well. In the head on shot of the front limbs, we see a very broad chest, but actually she is base narrow.
Conformation is a tricky thing when it comes to finding a ‘perfect’ horse, as I don’t believe that one truly exists. There are flaws in every horse if you look hard enough. The ultimate question comes as to whether or not those perceived flaws are truly a problem or an asset? One thing is certain, at least in my book , is that if we try to correct those perceived flaws through corrective trimming or shoeing, we will likely create more problems in the end. I believe that in the early stages of development and youth, many flaws can be corrected or encouraged to correct, but later in life, many changes occur as a result of those conformational abnormalities that may be exacerbated with forceful movements.
A horse that is toed out, for instance, will likely ‘wing’ during forward movement. If one was to look at the bottom of their sole prior to trimming, we would note that likely the inside wall of the hoof is worn more than the outside. With trimming, we can balance that foot, but it will return back to that state with time. It is nature and the way that it is. The opposite is true for a horse that is toed in, which results in ‘paddling’ during forward movement. Often, the outside hoof wall will be more worn that the inside. Again, we can balance the foot during trimming, but it will go back to that conformation with time.
Horses that are club footed are another issue and often, I see farriers trying to correct the problem by dropping the heels during trimming. A little is okay, in my book but too much leads not only to excessive tendon stress, but also we must remember that we are then altering the angles of the joint from the coffin to the fetlock. If those joints were used to being in a ‘club footed’ position with a set angle and we then change that angle, problems may develop with further stress on the joints.
We must remember that every horse is an individual with no one horse being perfect. There will be flaws, but that is okay. If we keep in mind those flaws, then we can try to work around them in the best manner possible, knowing that there will be some limitations, but also knowing that certain injuries or degenerative conditions may manifest as result. This discussion has been very general in purpose and more for demonstrations. Hopefully, it has helped us to see some of the variations that exist and how they can impact the horse.
All our best.
Tom Schell, D.V.M.
Nouvelle Research, Inc.