Many times our eyes are drawn to the feet of the horse, since this is our specialty as farriers. As we look at the feet, we might identify various issues that are going on.

But as we think about how to address those problems, are we looking in the right places for where they start? Does the upper conformation limit our ability to help the lower conformation? One horse in particular reminded me of the need to think about this.

A few years ago, an unwanted horse was donated to our farrier school. In fact, the 2-year-old horse was run through the sale ring but had no bidders (Figure 1). As far as we know, it had been pasture-raised and given little attention. We don’t know more than that, which is often the case when farriers come in on a new owner/horse situation.

The horse was difficult to work on due to its rare body conformation and lack of training. We kept the horse for 5 years as a unique example of various conformation deformities and deviations (Figures 2a and 2b). Our farrier students received terrific learning by seeing and experiencing an unusual live specimen.

We discussed and tried a variety of things to help this horse, as we worked on her on a regular trimming cycle. Each time she was trimmed, the hooves looked better. However, after 8 weeks, the hooves would revert to their deformed state. Nothing we could do corrected or changed the upper conformation.

Ultimately, we decided to put the horse down. This can be a difficult decision, but when problems continue to get worse, it is often the most humane thing to do. Before doing so, we decided to skip the regular trimming interval to exaggerate the effect of the unusual conformation on the growth of the feet.

Many stark observations can be made from this unique example. First, this horse had scoliosis, which is a lateral curvature of the spine. As viewed from above, an S curve can be seen in the spine (Figure 3), which is unusual for horses. As will later be noted in this article, this problem affects the growth and weight distribution of the lower legs.

Second, this horse had a kyphosis, also known as hump-back
or a dorsal curvature of the spine (Figure 4). This may also be referred to as a roach back. This condition alone can limit a horse’s ability to carry a rider. Lordosis or sway-back is the opposite, which is a ventral curvature of the spine.

Third, this horse’s left front leg was longer than the right front. Most likely this disparity was a result of the other problems. As you view the spine from the back of the skeleton, you can see the S curve, where the right side is lower. Each foot was different from the other.

FIGURE 1

FIGURE 2a left, FIGURE 2b right

FIGURE 3

FIGURE 4

Preserving This Case

When we first started this project, I contacted Allie Hayes of Horse Science, asking if she could freeze dry the lower legs and then make different cross-sections allowing us to view some of the effects of the upper body conformation on the lower limb conformation.

FIGURE 5

FIGURE 6

The sectioned, freeze-dried legs demonstrate these beautifully. It’s hard to realize what effect the bone structure would have on the legs just looking at the skeleton. The hooves capture that effect. It is almost unimaginable that the feet are so severely affected.

FIGURE 8

FIGURE 7

At the 2015 American Farrier’s Association annual convention, Hayes and I used this skeleton for an anatomy lab. It was interesting to see the reaction of the different participants. Most could not believe how bad or extreme this skeleton is. A few wanted a closer-to-ideal skeleton to compare in order to see how bad and rare this skeleton is. Several commented that they were drawn to the feet first — not even noticing the irregularity of the back.

This skeleton doesn’t have an odd number of bones as one might suspect from the usual 205 in a horse skeleton. It does, however, have an abnormal bone structure. There are several irregularities to note in relation to the scoliosis and kyphosis.

Some other observations could be missed depending on the angle or how it is viewed. When looking at the back from above, the ribs are racked or offset — the right side being further forward then the left. As you continue down the back, the lumbar vertebrae are all turned and diagonal from center line or axis, as part of the scoliosis (Figure 5).

FIGURE 9

FIGURE 10

Furthermore, this horse is an amazing specimen that presents many conformational limb deviations/deformities. These limb deviations originate from the back. It is important to discover the origin of each deviation and what will limit the horse’s ability for its specific needs/expectations. The hoof growth is affected by weight placed upon it from the limb above. For example, with this skeleton, the right side (RF) shifts down or is lower as the spine pushes to the right (as viewed from behind the horse). The hoof rolls under and has a crushed heel. The leg is fetlock valgus (toes out) and the hoof is affected by the conformation and position of the whole limb.

Examining The Feet And Legs

FIGURE 11

Below is a summary of further observations we made regarding each of the different feet and legs. Starting with the one that many might be drawn to first, as it looks the worst compared to the other feet. However, each foot is different and each has its own problems.

Right front (RF). This appears to be the worst of the feet when compared to the others. As viewed from the front starting at the fetlock, the conformation is fetlock valgus. If you visualize a perpendicular line through the center of each of the bones, you will see the leg is not straight (Figure 6).

The medial heel is rolled under and crushed due to the abnormal weight on this side. The lateral side of the foot is longer and flaring outward (Figure 7).

Now, if you add the rest of the leg and how it contributes to this conformation, the weight of the upper leg affects the bottom foundation. If viewed from above and looking down the humerus bone toward the ground, you’ll notice how the leg is rotated and twists inward. Then beyond the knee it goes in the opposite direction, outward (Figure 8). There are multiple rotational deformities.

This leg appears to be the shorter front leg. When looking down the back, you can see the way the tops of the thoracic vertebrae deviate where the back turns due to the scoliosis. Horse Science made two cuts medial to lateral, showing the inside of the lower leg and foot. The medial side of the bone is longer than the lateral side. The cut that is in the middle shows the beginning of a bone degeneration on the end of P3 (Figure 9).

FIGURE 13

FIGURE 12

Left hind (LH). This is the diagonal limb to the right front and shows some opposites. For example, instead of being valgus, this foot and lower leg are more varus. The foot rolls under and crushes on the lateral side and the hoof growth is longer and distorted on the medial side. It is interesting to note when viewing the inside of the foot that the size of this foot is smaller in comparison to the others.

Similar to the RF, if you visualize a line down through the center of the bones, you can see how twisted they are (Figure 10). Even the cannon bone is twisted and curved. Not level, the hip appears to be higher on the left side and lower on the right side.

Often in a limb length disparity you’ll see a discrepancy in the diagonal limbs. Not so here. This skeleton shows that the RF is the short leg and the LH (where the hip is higher) is the longer leg. Most horses with limb length disparity have diagonal legs that are similarly affected, meaning both are shorter or longer (Figure 11).

Left front (LF). It could be assumed that because of all of the irregularities in the RF, the LF (the contralateral limb) would have taken the extra weight and caused a compensatory lameness. The horse doesn’t appear to have any of the common signs of a foundered foot. This horse carried its weight on the front end more evenly than we suspected.

This hoof does have a low heel and longer toe. The fetlock appears to be bigger. When viewing the inside from the cut that was made, the bone looks thicker and appears to have a problem with the outside collateral ligament (Figure 12). There is a flexural deformity as the hoof pastern axis (HPA) is broken back.

Right hind (RH). This foot and lower leg appear to be closer to ideal than the rest of the legs and feet. When you view the digit from the lateral view, the fetlock looks knuckled forward (Figure 13). When you look at the mid-sagittal view you can see the thickness of the bone. In viewing the cross section, the bone does look thicker. The bones of this leg, and especially the foot, are small for the size of the horse.

Lesson Delivered

By now, you’ll acknowledge that this is a rare skeleton. It provides a great review of anatomy, balance, conformation and a reminder of the effect of limb deformities/deviations. As we study different examples like this, our horse knowledge and experience increases. We have a better idea of what problems can be helped or not.

This skeleton illustrates how the upper conformation influences and affects the lower conformation and what we may or may not have influence over by trimming and/or shoeing. With each horse we work with, we need to look at the whole horse, not just the feet.