Hoof Distortions and Other Causes of Lameness
Hoof distortions are not uncommon in our domestic horses.  Distortions  are either genetic or result from injury or other
causes.  Some other hoof distortions are entirely man caused, and are the result of long term improper trimming or shoeing.  
Thanks to Gene & Cody Ovincek of Hope for Soundness and the Equine Lameness Prevention Organization for
providing these important illustrations of hoof distortion.
This should be a pretty good attention getter to illustrate the
importance of proper trimming and shoeing!
Notice three nails driven from the bottom of the foot and sticking out
about half way up the hoof wall!  The horse had no pain and not a
drop of blood resulted from this dramatic illustration of distortion
caused by improper long term shoeing (or trimming).  The V shaped
lines overlaid on the photo represent the position of the coffin bone
within the hoof capsule.  The horse was likely shod or trimmed
continuously with the heels long and to try to keep a correct pastern
alignment the sole under the coffin bone would be thinned.  This
results in a forward "migration"  of the toe hoof wall.  Look at the hoof
just under the hair line, note the steeper angle of the hoof?  This is
the angle the horse would
like the hoof to grow but the constant
stress of the long toe caused the hoof  to distort forward.
The bottom photo shows the actual position of the coffin bone in a
foot with similar distortion.
Don't get the impression this distortion is okay because this horse
didn't feel the nails driven up through the foot.  The damage from this
type of hoof distortion is
silent, and has a significant affect on the
long term soundness of your horse.
A horse is intended to walk pretty much like you and I, with each footfall landing on the heel and rotating to the toe before the
foot leaves the ground again.  This is extremely important in horses as a heel first landing sets up the proper alignment of the
distal interphalangial joint (IPJ) and uses the frog, heel bulbs and digital cushion to soften the impact of the footfall.  

Watch each of your horses feet closely to see if they are landing toe first, flat, or heel first.  Little puffs of dust or kicking dirt
our in front of the foot is a pretty good indication of a toe first landing.  Heel first is ideal, flat is acceptable, toe first is
damaging.  Most horses with a good heel first landing have a pretty way of flipping the hoof out just before the hoof descends
to the ground.  The following illustration provides an example of the joint alignment desired during a heel first landing, as
compared to the joint alignment the horse experienced during a toe first landing.  The little bone at the back of the coffin bone  
is the navicular bone.  It is the pressure exerted on the navicular bone during a toe first landing that can lead to navicular
syndrome, or simply heel pain.
This animated illustration shows how a hoof can become distorted from improper
hoof care.  
The red line through the center is the widest part of the hoof sole.  The widest part of
the hoof sole is determined by the location of the coffin bone within the hoof
Regardless of how distorted the hoof becomes the widest part of the
hoof stays in the same place,
what changes is the amount of hoof on the ground in
front of and behind the widest part of the hoof.  A healthy hoof is one where at least
50% of the hoof that touches the ground is BEHIND the red line.  
  1. The first illustration is the one that has the most round shape and the widest
    frog.  This is a Natural Hoof with about 50% of the hoof behind the widest part
    of the hoof.  Most horses, before they ever become shod have a foot pretty
    similar to this shape.  Important features of this foot are; A. a short distance
    from the widest part of the hoof to the toe and a greater distance from the
    widest part of the hoof to the back of the  heel.  B. A wide frog and large heel
    bulbs (dark grey at the very bottom of the illustration.  C. The bars are straight.
  2. The second illustration shows the beginning of hoof distortion.  The toe has
    moved farther forward from the widest part of the hoof, increasing leverage on
    the IPJ.  The heels have become longer, beginning compression of the frog.  
    The heel bulbs lose some of their shock absorbing capability.  The depth of
    the foot between the heels and the frog increases, creating a bacteria trap.
  3. The third illustration shows the continuing increase in toe length.  The foot is
    becoming oval and appears narrow compared to the first slide.   The long heel
    creates forces on the bars that will often cause the bars to curve and often
  4. The fourth through sixth slide represent the continuing distortion of the hoof
    caused by improper shoeing or trimming.
                              THE GOOD NEWS IS........HOOF DISTORTION IS REVERSIBLE!!
As fragile as our horses sometimes appear to be,  they are very forgiving, and most often the horse can return to a Natural
Hoof and long term soundness is very likely.  Proper shoeing (yes I said it!) using Natural Balance Shoeing methods, or
trimming, using Natural Hoof Care practices can return most feet to the fully functional foot in less than a year.
Not all lameness is caused by improper shoeing or trimming, conformation or injury.  Metabolic conditions in horses frequently
precede lameness.  This
article appears with the permission of Kathy Newcomb and The Morgan Horse Magazine.  How you
feed your horse and how much exercise you provide has a lot to do with their long term health.
Break over is the place on hoof sole hoof that is bearing all the weight the moment the heel leaves the ground.  A long toe
delays breakover and causes undue stress on the Deep Digital Flexor Tendon (DDFT)   Ideally, the heel should leave the
ground with minimal stress to the DDFT.  Reducing stress on the DDFT is attained by providing a toe that ends closer to the
tip of the coffin bone (below left) not long and distorted as shown (below right) or in the animated illustration above.    
As contradictory as it may seem, long heels actually add stress to the joint structures as well because the angle within the joint
(as seen on the right) needs to become sharper before the heel leaves the ground.  
Restoring the hoof to a natural state will bring the breakover "back" closer to the ideal location.  Again, this promotes long
term health in your horse.
This is just a glimps into this important article by Gene Ovnicek.  
Click this link to get the full story on
How Hoof Form Relates to Hoof Function.