Much lameness in horses is attributable to foot pain and many causes of foot pain are directly attributable, or more likely to occur, if the feet are the wrong shape. As a practicing veterinarian, a large proportion of my work is looking at lame horses and the source of the lameness is more commonly in the feet than in any other part of the limbs. Usually there is no palpable swelling or site of pain in the limb and therefore clients frequently assume it to be a “shoulder lameness”. I always find bizarre because conversely, shoulder lameness is very uncommon. So, most vets always start looking at the feet first when considering a lameness and work up the limb. If one starts at the feet and the first thing one notices is abnormal foot conformation, one should always be suspicious that this might be the seat of pain.

Abnormal foot shape is associated with increased risk of lameness from a long list of conditions which include: solar bruising, heel bruising, solar abscesses, tendon strains, suspensory ligament strains, navicular bone disease, coffin joint arthritis, pastern arthritis (Ring Bone), fetlock joint arthritis, hock arthritis (Spavin).

Biomechanics is the study of forces and movement of specific structures of the limb at different paces and is a fascinating area of current research. The shape of the foot and how it lands on the ground and takes off (or Breakover) determines many of the stresses involved in the whole limb.  It is far too simplistic to say that you can prevent, for example, navicular disease by having good foot shape and conversely it is too simple to say that navicular disease is due to poor foot shape, but most vets would consider it highly important.

Normal Foot Shape

As always when looking at a whole population, there is no one shape that can be considered “normal” for all horses because there is always a range of normality. There are also breed differences, for example, Quarter Horses have narrow, upright, boxy feet, small relative to their body size, European Warmbloods have relatively tall narrow feet and Thoroughbreds tend to have rather longer toes and lower heels.

However, it is generally agreed that from a biomechanical point of view there is a blueprint of a foot shape that most horses should aspire to.

This article is limited to considering the shape of the foot as viewed from the side. However, also of great importance is the shape and symmetry when viewed from front to back or medial-lateral balance.

The diagram below (Figure1) shows the relationship between the hoof wall and the underlying anatomy.

Figure 1 - Foot Anatomy



The next diagram (Figure 2) shows the same foot with some lines drawn to show how the hoof shape of a normal foot should look and gives some guidelines on how to visually assess foot shape.

One blue line runs along the front of the hoof wall from toe to coronet and another along the line of the heel and a third line traces the angle of the pastern (make sure the horse is standing square with a vertical cannon bone). These three lines should all be parallel to each other. These lines can easily be assessed visually but having someone hold a straight rod or ruler to your horse’s foot while you look from the side will aid your assessment.

The angle of the pedal bone in relation to the ground is very important. The red lines show the correct angle of 10 degrees.

The considerable weight borne by the foot should be equally distributed over the whole of the foot where it makes contact with the ground. If a vertical line is drawn from the centre of the coffin joint, it should equally bisect the ground surface of the foot. In figure 2 this is shown by distance a = b.

Figure 2 - Correct Foot Shape

The commonest abnormality of foot shape is known as a broken hoof/pastern axis or a long toe/low heel and is shown diagrammatically in Figure 3 and in the photograph in Figure 4. This tends to occur due to the interval between trimming and shoeing being too long or inappropriate farriery whereby the toe is not trimmed back far enough and/or the shoe is fitted short at the heels. Consequently, the weight of the animal increases onto the heels.  A vicious cycle can then ensue whereby the heels further collapse due to increased load and the toes become longer and longer. The angle of the pedal bone tends to 0 degrees or may even become negative.

Figure 3 - Long Toe – Low Heel Foot Shape




Figure 4



The consequences of this abnormal foot shape are potentially serious. Imagine if you were made to walk or even perform athletically in shoes with no heel and a built up toe. The whole biomechanics of the foot and its associated ligaments, tendons and joints become altered resulting in unnatural stresses and strains on these structures. The foot becomes flat and the sole instead of being a convex shape becomes flat or even convex resulting in a high risk of solar bruising, penetrations and abscesses. The horn of the hoof wall also becomes weakened so the hooves become prone to cracking and breaking making it more difficult to retain shoes.

It is not always easy to visually determine subtle abnormalities in foot shape and x-rays are very useful in looking at foot shape and the relationship of the pedal bone to the hoof wall and a great aid to farriers. If in doubt ask your vet to x-ray the feet and view the pictures with your farriery. Remember, in the vast majority of cases this sort of abnormal foot shape is correctable given time and remedial farriery. The owner must be prepared to pay for different shoes and more frequent trimming and re-shoeing. But much better to do this and prevent serious lameness.

... Read Mike's next article on tendons and ligaments, coming soon.

If you have experienced a horse with foot problems and can offer any helpful advice which you would like to share with other readers, please email us at enquiries@manedealer.com