article
Relationships between hoof,
leg, and whole-horse
conformation
By Monique Craig
Monique Craig is a hoof researcher, farrier, consultant to farriers, rider, trainer, and founder of EponaTech (www.EponaTech.com)
and EponaShoe (www.EponaShoe.com). She founded a research institute dedicated to research on equine biomechanics (www.
Epona-Institute.org)
In a broad sense, most readers would probably agree that there is a frog toward the bulbs) can be regarded as functioning as a pad. Shifting
relationship between hoof conformation and the conformation of the the load to the toe area has serious consequences on the health of the
whole horse. But how does one assess the consequences of poor hoof pedal bone. Internally, the arches should have a good definition. The sole
conformation? should be at least half an inch in thickness or more. The sole plays an
This is the million-dollar question that may be hard to ever fully answer!
important part in supporting the entire limb. It acts as a shock absorber
To understand the ramifications of hoof conformation as it relates to the
and provides insulation against the cold and heat. If possible, the hoof
horse, we need more information on equine locomotion, biomaterials
should not present internal pathologies, that is, articular ringbone, nor
mechanics and equine neurology. When compared to human
external abnormalities, such as permanent scars on the hoof capsule.
biomechanical research, equine research is in its infancy. Generally
Ideally, the hoof should be able to function as intended. This means
speaking, the study of biomechanics is a relatively new field compared to
that the sole, walls and frog should share the load and be able to flex
that of the well-established fields of biology and physiology. There is still
according to their normal mechanical properties.
much to gain from exploration of equine biomechanics.
Due to the complexity of the subject, I will broadly discuss hoof
conformation as it relates to the stance of the horse. Also, I will try to
address the difference between external hoof conformation and the
shape of internal structures. For instance, a hoof may appear externally
to be ‘normal’ but may have internal deformities. What effect do these
internal deformities have on the horse? It is important to point out that
any quantitative definition of ‘normalcy’ ought to refer to an acceptable
range rather than an exact number.
Fig 2. This image shows models of the bones that were
reconstructed from a radiograph of the same horse, so that we
can visualise the approximate positioning of the bones within
the lower limb. This horse has a poor stance. The hoof is not
beneath the bony column of the leg – it is ‘out in front’
Fig 1. The radiograph shows a hoof that has a good stance. The
arch (red curve) supports the larger part of the pedal bone.
The vertical green line intersecting the pedal bone is placed
Now let us examine what could happen when a hoof deviates from the
approximately where the apex of the frog would be. As one
norm. Fig 2 shows a horse with poor stance conformation, the hoof is
can see, a large portion of the hoof lays behind this line. The
too far ahead of the bony column (cannon bone) and the bone alignment
two solar pictures of the hoof show two different hooves with
is not ideal. This poor lower limb stance may affect the conformation of
reasonably good conformation. Note that a larger portion of
the horse. It is likely that as the bone alignment within the hoof changes,
the hoof is behind the red line in the two solar views it will also have an effect on the entire frame of the horse (Fig 3).
Fig 4 shows a ‘before/after’ sequence of the same horse whose stance
My ballpark definition of a ‘normal’ hoof is this: the hoof ought to stand
was improved through trimming and shoeing techniques. Support points
under the bony column and have heels that provide adequate support to
at the heels were ‘moved back’ over time and the width of the heels
the bulbs (Fig 1). A higher percentage of the hoof should be behind the
were increased. At the same time, the horse’s stance became more
apex of the frog, than in front of it. It makes sense to have a larger load
‘upright’ and stood under itself better.
percentage present in this area rather than at the toe. The caudal area of The changes in stance and hoof conformation (Fig 4) raise a question
the hoof (approximately, the region that lies behind the middle part of the about the meaning of ‘true’ conformation of a horse. I feel that before
4 Forge | October 2009
Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48