Anatomy of the Foot

Introduction

Rather than just a big toenail or a lump of dead horny material on the end of the horse’s leg, the foot of the horse is a highly complex ‘elastic’ organ which performs a wide variety of functions which are vital to the overall health and wellbeing of the horse.

Shoeing and improper/unsupportive trimming techniques, which run rampant in the horse world today (and yesterday), impair the vital functions of the foot and are the root of many, if not all of, the common and prevalent lameness problems. Things like founder, laminitis, hoof wall cracks, navicular disease/syndrome, thrush, WLD, ‘mystery’ lameness …

Combine this impaired function of the foot with an unnatural lifestyle and you can write an encyclopedia of maladies that affect our horses.

In addition to all the lameness issues, there are behavioral and training issues to deal with. Things like cribbing, stall walking, weaving, biting, kicking, aggressiveness, colic, immune deficiencies, skin and coat problems, etc … the list goes on.

Many of us are ‘ignorant’ of the normal shape and function of the horse’s foot. This includes the vast majority of vets and farriers. We are blindly told to trust our farriers and vets to know what is healthy and ‘normal’. There is a fundamental problem in doing this and the problem lies right in the conventional education process. The text books … and I have PLENTY … are chock full of improperly shaped feet that are labeled as normal or healthy. The anatomy drawings, photos and conformation shots show horses with high heels and shoes. Shoes are not part of the horses’ anatomy or physiology. High heels are counterproductive to the function of the foot and have a detrimental effect on the entire being. The text books are showing unhealthy feet with improper function and labeling them as ‘normal’. While normal and common they may be … they are counterproductive to the horses’ health.

Because of the amazing capacity of the horse to adapt and to bear pain, many, many things go unnoticed and undiagnosed until this innate ability to adapt has been stretched to the limit and the system begins to crash. There are many signs this is happening – lameness issues are just one sign. Drug therapy and ‘corrective’ shoeing and ‘educated’ guessing seems all there is left to do to get a ‘few more years’ out of the horse. Hock and joint injections are super common among competition horses and totally not necessary if their underlying problems in the shape and function of the foot were properly addressed.

Meanwhile the horse suffers in silence and very few complain. Those that do are deemed ‘bad’ or gone mad. Get out the bigger whips and chains and the stronger drugs to sedate them.

It amazes me every single time the capacity of the horse to heal himself if he is given the medium to do so.Be true to the Nature of the horse … and you can’t go wrong.

 

 

The Bones of the Foot and lower leg

bones boneThe bones of the horse’s foot can be referred to with many different names.
I’ve labeled some photos and drawings to help sort out the confusion.
The Coffin Bone is also referred to as the Pedal Bone or PIII or Third Phalanx.
The Navicular Bone is also referred to as distal sesamoid.
The Short Pastern Bone can be called P2 or Second Phalanx.
The Long Pastern Bone can be called P1 or First Phalanx.
Really LOOK at the pictures above. Look at the coffin bone and see how it is shaped. You can see where the frog apex would join. You can imagine why a cross section view of this bone gives the appearance of being a small triangle pointy bone when in fact it is a large ‘hoof’ shaped specialized bone.
The coffin bone is very perforated, resembling a (hard) sponge. These porous ‘holes’ allow tiny branches of arteries, veins and nerves to pass through the bone.
Attached to the ends of the coffin bone are the lateral cartilages. They are affected by shoeing and conventional trimming.
It has been proven that shoeing or improper trimming restricts and alters the normal intended movement of the foot, restricting the blood supply to the foot. Overall circulation is compromised. Nerves are pinched and function is reduced as well. This may be one reason why shod horses ‘appear’ sound when in shoes but ‘dead lame’ when out of them.
Some people still think that ‘some’ horses can’t go barefoot. I beg to differ. ALL horses will benefit from assigning the foot it’s intended form and function. The body systems will respond – the immune system is raised – health is elevated.

Properties of BONE

Bone is dynamic, living tissue! The main structure of bone is calcium and phosphorus, but bone also contains blood vessels and specialized cells called osteocytes.Calcium and Phosphorus is required for many other bodily functions, including muscle and nerve activities. One important function of bone is the storage and release of these minerals, depending on what the body requires. Another important activity of bone is growth (in young horses) as well as adapting to the stresses and strains of everyday life … and increased exercise in the form of riding or driving, etc.
Like any other tissue in the body, bone is constantly active. It is always busy replacing cells, laying down or absorbing mineral deposits. The bones are also constantly responding to the forces they receive.
Continuous free exercise … like living a Natural Lifestyle increases bone density. In other words, being stalled or inactive decreases bone density. This process is the bones normal response to the forces it experiences and is called bone remodeling. It can remodel to be stronger and denser or it will remodel in the opposite direction.
Being born and then living with unrestricted movement increases the loading capacity of the bones of the legs and foot. A certain amount of concussion is needed to build strong bones. Much more than we are led to believe. Being stalled on soft bedding or living and working on soft footing and wearing steel shoes are all counterproductive to the bones.
Did you know that several weeks of ‘stall rest’ commonly prescribed by veterinarians results in bone demineralization and reduction of bone density … also know as osteoporosis!

cn coffin

Corium

The corium is considered the ‘sensitive’ structure of the foot as it contains the nerves of the foot. The corium is modified skin tissue that is highly vascular. The corium nourishes growth. It also dissipates heat and concussion.
The corium can be divided into the following various sections:
The coronary corium is responsible for growth of the hoof wall and is located inside the hoof capsule all around the upper perimeter of the hoof (coronary band) to the bulb/heel area where it turns sharply inward and produces the bar.
The Perioplic corium is a narrow ring of skin located around the top edge of the hoof. It produces the periople, that skin like appearance covering the top of the hoof wall. It has a high water content and can dry out quickly … but also absorb water quickly. It’s interesting that the periople was ‘discovered’ and named by Bracy Clark almost 200 years ago … but the history of horses and people/shoeing goes back thousands of years. It makes me realize and wonder how many other things have been overlooked or misunderstood on the intricate biological makeup of the horse.
The Laminar corium covers the frontal surface of the coffin bone and lower edges of the lateral cartilages. It provides nourishment to the laminae which in turn connects or suspends the coffin bone inside the hoof capsule. When the laminae do not or cannot produce good quality horn (because of restrictions placed on the movement of the hoof/horse and/or diet issues), the tight connection is compromised and can be lost when the force of the descending coffin bone causes the layers to shear.
The solar corium covers the solar part of the coffin bone and of course is responsible for producing the sole. The solar corium is less dense than the coronary corium, therefore the sole is not as hard as the wall. It is still susceptible to drying out, though not as much as the white line.
The frog and bulb corium produce softer elastic horn having a high moisture content.

ft cap

 

Joints, Tendons, Ligaments and Cartilages of the Foot
The bones of the foot are held together by ligaments that are especially reinforced at the sides.
The lateral cartilages are found on either side of the coffin bone. They are attached through ligaments to the coffin bone, short and long pastern bones and act like an extension of the ‘wings’ of the coffin bone (palmar processes). So it would stand to reason that what happens to them also affects the bones and ligaments nearby.
The extensor tendon runs along the front of the foot and the flexor tendons along the back. The flexor is attached to the solar part of the coffin bone, the short and long pastern bones as well as the navicular bone.
di ss
The Lateral Cartilage is palpable (meaning that you can feel it) as well as pliable (meaning that it is easily influenced or altered). It is adaptable (to a point) and flexible. The lateral cartilage is ‘soft’ compared to bone. It responds to the shape of the harder hoof wall, as well as any internal forces. Cartilage function becomes impaired by nailing on a shoe, or improper hoof form caused by ‘conventional’ trimming.
You can train your eye to ‘see’ the lateral cartilage. It is a BIG indicator of what is happening on the inside of the foot. It sometimes reflects itself in the shape and angle of the hairline at the coronet band.
lc lcb
drdIn the picture on the right, one foot is trimmed ‘naturally’ (performance trim) and one foot is trimmed ‘conventionally’ (pasture trim). For more information on the differences between pasture trim and performance trim check out theTrimming Differences page. (coming soon)
The picture below is an extreme case of high heels. This horse was also chronically foundered (wonder why?). He was also on medication for heaves and had MUCH difficulty breathing.
One foot is trimmed and one is yet to be trimmed. This was the initial trim of this horse and I took the picture lying down on the floor behind and between the hind legs…phew! You can see the relief and relaxation of the trimmed foot and how easily influenced the lateral cartilage is. Imagine the long term chronic pain this horse was dealing with.
In addition to medication for ‘heaves’ and ‘founder’ he was confined to the stall because of his ‘illnessness’.
hhh
Today, at 18 years old he is full of life and vigor. He was taken off all medication once he was started on the ‘program’. He got a new lease on life … and a new body and feet rebuilt. He did this in less than one years time … and he’s not alone. It is amazing each time for me to see these ‘hopeless’ cases come full circle. The power of Nature is awe inspiring!

FOOT SHAPE

SO many of today’s horses are given a high heel foot shape … or they are trying to “stand them up” or “get more heel”. If that’s the case, the heels are generally underrun or crushed.
The concept or idea of a horse with a ‘good’ heel is very misunderstood and thought to only mean the length of the heel wall. In actuality the heel is an area of the foot which includes the external structures of the hoof wall, the heel/bar triangle, the back of the frog and the heel bulbs … but also includes the internal structure of digital cushion. The digital cushion is often crushed and atrophied when not put into proper use from too ‘high’ a heel or when bounded with an iron ring.
People are led to believe that a desirable hoof has lots of heel (heel wall) … the truth is, this kind of shape is the cause of many a lameness issue. The results of the trimming styles that accompany shoeing or conventional ‘pasture trims’ are contraction, decreased blood flow, decreased nerve function, bar impaction, heel pain, mystery lameness, founder, etc. The resulting chronic low grade pain can be related to behavioral and training ‘problems’ as well.
The digital cushion is often misunderstood or completely ignored. It requires the natural expansion and contraction (restricted, altered or eliminated by shoeing or improper hoof shape/trimming) that the horses foot has upon impact through movement. The digital cushion plays an important role in pumping the blood through the foot. Movement is important and standing still for 1/2 days or more does nothing to develop this built in ‘Air Nike’.
The bars of the foot are made of very hard horn material and if not trimmed correctly or receive little wear will grow and jam up inside the hoof capsule. In essence ‘squish’ and pinch the digital cushion and lateral cartilages … among other things. The picture shows this happening to this horse’s foot. He was diagnosed with a neurological ‘disease’ when the real reason was right there in his hoof form. NO vet or farrier commented on the feet … they were ‘normal’ for him. Once his trim style was corrected, he no longer showed the symptoms of this neurological problem that the conventional professionals believed he had. He had NO symptoms less than one week later.
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