As people who care for horse’s hooves, it behooves us to know as much as possible about this structure. Yes – pun intended. We as horsemen need to understand how the entire leg is made and how it all works together. I know we have seen many of the moving parts, either while we hold the hoof in our hands or while watching the horse move. But what do we really know about the hoof and the leg? We can read the books, practice on cadavers, do our homework but the learning process never ends.  
While out riding I came across a scattered skeleton of a horse. Oh what an opportunity to study the bones. But amongst this was one intact front leg. Not only was the leg intact but the hoof capsule was still attached, complete with a shoe! Oh wow!
Studying the foreleg becomes important when we realize that all these bones and joints, cartilage, tendons and ligaments, are greatly affected by concussion. The effects of concussion become greater when the hoof is trimmed out of balance. When the hoof is out of balance, the bones are no longer properly aligned as intended by their creator. This in turn causes an imbalance through the leg and contributes to lameness. This is a left front leg; I have labeled the larger bones. However the pastern consists of the long and short pastern bones, also known as the first and second phalanx. The third phalanx, commonly called the coffin bone, is inside the hoof itself. The fetlock joint houses the ankle and sesamoid bones.
The view above shows the front and top of the hoof capsule. It is separating at the area called the coronary band, which compares to the cuticle for our fingernails. The coronary band feeds the hoof. Any injury to the coronary band, split or wound, grows out down the hoof wall. An abrupt shock to the hoof’s circulation (such as founder, illness or fever) often creates a band or ring in the hoof wall. These hoof scars inform us about how healthy the hoof is on the inside beyond what we can see. The marks are visible for approximately one year, which is the amount of time it takes the average horse to regrow the hoof. 
Keeping concussion and balance in mind, take a look at how delicate the fetlock and the carpal bones are. It’s no wonder horses develop lameness and arthritic conditions due to pounding and zillions of steps in their lifetime.  

The hoof capsule itself is an amazing structure filled with hundreds of capillaries and vessels to circulate the blood throughout the hoof. While the hoof appears rigid, it is very elastic and flexible. It contracts and expands with every step which pushes the frog and pumps blood through the hoof. This blood has a huge area and many parts to circulate through as it feeds all the tissues. I have labeled the outer regions of the hoof; there are many more parts and pieces inside the hoof. 
In addition to the bones there is a myriad of tendons, cartilage and ligaments that hold all this together and make it work as one unit. So many amazing parts and pieces! I find it fascinating. Especially since I do horse massage and have helped release the tension and soreness from over use and imbalance. 
Karen Bumgarner