VET NOTES l ANATOMY OF THE HORSE
How does a horse’s anatomy compare to a human’s? There are stark differences as well as a few similarities, but also areas that make him particularly vulnerable to injury, as Your Horse’s new resident vet Lucinda Ticehurst explains
VET notes
WHAT YOU’LL LEARN:
● Why a horse’s front legs are so vulnerable to concussion
● How to reduce the risk of overloading strains within soft tissues
● What to consider when starting a horse in work
AHORSE’S ANATOMY differs significantly from a human’s due to the evolutionary adaptation for different modes of locomotion and environmental demands. Evaluating our structural and functional differences (and similarities) can highlight vulnerable areas and help people to manage their equines to reduce risk and keep them injury free.
If we look at horses in their natural habitat in the wild they cover vast distances and are designed to protect themselves through the flight instinct. They are built for speed and endurance, with a powerful push-off and stride extension. Humans are designed for stability and flexibility and are more able to adapt to a wider range of terrains.
Horses are quadrupeds and move on four limbs, while humans are bipeds who move on two limbs only. Four legs enable a stable base with four points of contact with the ground. This facilitates carrying heavy loads or moving on uneven terrain.
Quadrupeds can move in various coordinated gaits:
■ Walk
■ Trot
■ Canter
■ Gallop
They use different combinations of their four limbs to create specific movement patterns. This versatility in movement allows them to adapt to different situations and environments. The weight of the animal is also distributed over the four limbs which reduces the pressure on each individual leg, this being advantageous for avoiding strain and injury.
Adaptations through history
With equines specifically it is important to consider the make up of their distal limbs. In contrast to many other species, horses’ limbs terminate on a single column of bones.
The early ancestor of the modern horse lived around 50 million years ago. They had four functional toes on the front limbs and three on the hind. These toes were used for running and grasping vegetation. Over time the horse experienced environmental changes, including shifts in habitat and climate. This resulted in the middle toe becoming the most functional and important for supporting the animal’s weight during rapid running.
Over millions of years the side toes became smaller and less functional. They no longer made contact with the ground during locomotion and the process of reduction continued until eventually only a single, fu
