Whereas structurally asymmetrical horses are rare, horses that are in the habit of leaning and traveling crookedly are nearly universal in the domestic horse population.

There are many differences between the skeletons of horses and humans. One that needs to be clear in the minds of all farriers — and all riders and trainers, too — is the fact that humans have collarbones while horses lack them completely. The consequences of this difference impact every aspect of horsemanship, and that certainly includes the form and function of the equine hoof.

At the most fundamental level, reciprocation means energy exchange between linked parts of a biomechanical system.

At first glance, the stifle joint appears to be a huge mistake — the worst-designed part of the musculoskeletal system.

Weight-bearing upon flexed hocks puts enormous strain on all parts of the hock joint. Along with the equally complex stifle joint, the hock is crucial to the horse’s ability to flex and extend the hind limb and create the forward thrust that is the “impulsion” so often sought by horse owners who compete in the Olympic disciplines.

Throughout this series, I have illustrated the concept of systems anatomy. Veterinary education and that of traditional farriers are based on regional anatomy, which studies regions and the anatomical components of each. The perspective of systems anatomy is that bodies are organized hierarchically, i.e. building up from small functional units (for example, cells or single tissues) to subsystems (for example, organs), which work together to make up a major system such as the nervous, circulatory or musculoskeletal system.

Over much of the past year, through this series I have presented the building blocks of information needed to understand the structure of the forelimb reciprocating apparatus in horses. Starting from collagen and elastin at the molecular level and working through all the various connective tissues structured by those two molecules, you have had the opportunity to learn equine anatomy and terminology as enrolled university zoology, pre-medicine or pre-veterinary majors would.