Ever wonder whats going on inside your horse's hoof?
Here's a decent looking internal view of a hoof. The toe is awfully long but sole is thick and coffin bone is a little lower than it should be but still a good idea of what it should look like in there. triangular looking bone (only in sagittal view does it appear that way) is the coffin bone. above that is p2 and above that is p1. the small bone under p2 is the navicular bone. you can also see the flexor tendon that runs along the back of it pretty well. and the sole area you can see the digital cushion.
here's a severely foundered foot. super thin sole and eroded coffin bone. this is what happens when founder isn't addressed and the horse is left to continually suffer through founder cycle after cycle. bone does not grow back! so once this damage is done, its done. thats not to say that a horse like this couldn't be made comfortable again. but very unlikely it would be rideable or good for anything other than a pasture pet. in my opinion this is a gross count of animal abuse. the pain involved is excrutiating and so easily avoided if the owner takes notice and does something to fix the cause of the founder.
here's a look at the coffin bone as it fits inside the hoof capsule. fits perfectly! easy to see how the constriction of a shoe and lack of natural expansion could remodel the coffin bone shape in a young horse. why do we insist on "improving" what nature has so fantasticly provided???
an inside look at the lamina that lock together and form the velcro that holds the hoof together.
Fresh cut sagital of a pony with major high heels and extensive lameller wedge at the toe. see how steep the angle on the coffin bone is? this is whats referred to as coffin bone rotation. easy fix on this little guy would've been to lower those heels and get the natural angle back in that coffin bone. no doubt this poor pony was diagnosed as navicular, based on this internal view the diagnosis would've been wrong. its the stress we place on the flexor tendon when the heels get jacked up that cause the problems and pain. reverse this situation and voila, sound pony again. too little too late for this guy.
A better view at the lamellar wedge at the toe. its that yellow colored material. this is what fills in when the lamina are torn apart from each other. there can't be a gaping void so instead the hoof grows a filler. its weaker than regular horn material but better than a gaping hole.