The 1st Grader Version of Equine Limb Anatomy

ORIGINS: Part one of I-don't-know-how-many-installments

I know many of us have read about the hoof in its structure, function and composition. This article is not to appeal to the doctorate-level, thesis-composing hoof experts of the world. This is less flourishing quill and more Crayola crayon.

Before talking about the anatomy that IS, I would like to take a trip down memory lane and see how that anatomy got here. I am writing this from a point of curiosity...and I want the everyday horse owner to learn more about the past to understand the functions of the present.
 

f

Let's say you weighed 50lbs, were 14 inches tall and about 2 feet long. You were roughly the size of a Cattle Dog.

    

Your leg structure didn't look all the different from a cat or a dog.

You were a tiny little beast.

You had four, hooved “fingers” on each foot, sort of like a tapir.

Let's give you 20 million years to evolve.

You lose ONE toe from functionality. Some say that bone shifted up and back and became the ergot, due to the horny composition and location of the ergot, similar to the consistency of a hoof (like a dewclaw in a dog):

Some think it became the chestnut on a horse, also due to the same horny composition:

You now only have THREE toes:

      

You get a smidge taller. Now you are 24 inches tall or roughly the size of a Golden Retriever.

Another 15 million years go whizzing by.

Your three toes do a little rock-paper-scissors and decide that the middle toe was doing all the work anyway. Your side toes get a bit smaller and shorter and let the middle toe take the driver's seat.

  

 

This is convenient that someone took the leadership role, because you almost doubled in height and all that weight needed to be supported somewhere. Now you are just over 3.25 ft tall, taller than a male Great Dane.

  

In other words: Giddy-up, prehistoric Great-Dane-sized pony creature!

Before you know it, 7 million more years have passed and your two side toes have said, "Sayonara." They slipped back into a supportive role by your "shin". They pass down the left and right side of the cannon bone and support it, or "splint" it.

If you’ve heard of splint bones, now you know what they were. They were digits 2 and 4, who slid up the main bone (3) and splinted it, as supports on both sides.

See? Just like how we splint body parts: one support on each side.

Those splint bones aren’t that thick. Horses pounding hard ground can cause injury to their splints. They can be kicked, dinged in a trailer or receive concussion from the lower portions of the limb. As a result, some horses will “pop a splint” or have a raised bump along that bone (on either side). This is the slender bone trying to reinforce itself, either by adding more bone or scarring tissues. Some horses live fine with their “popped splints”, some need them removed as they rub along delicate tendons in the legs and cause more damage.

At this point, 7 million years ago, your pasterns are super short and your cannon bones are quite long, but you are essentially "done" changing your leg structure to support yourself.

Coming forward another 6 million years and you've made your final adjustment:

  • Your pasterns got a little longer in proportion to the rest of the leg
  • Your cannons got a bit more compact
  • Your bottom bone, P3 or the "coffin bone", gets a bit larger


Now that we're caught up on evolution, we can pause to look at what our horsey limb parts DO.

How would you design your legs to work if you had a choice?

STAY TUNED for next the next installment: FUNCTIONS

Holly Jonsson

easycare-sales-director-holly-jonsson

Director of Sales

Through a lifetime of "horse crazy" and the fortunate experience of riding nearly every shape and size of horse, I got to see a wide array of hoof shapes and sizes. No Hoof, No Horse is very true to me. I want to ensure that horses on every continent have a variety of footwear to pick from, to ensure the best match is found. I want your partner to be happy from the ground up!


Comments for The 1st Grader Version of Equine Limb Anatomy

blog comments powered by Disqus