Horses have one hoof at the end of each leg, unlike their hooved counterparts with a split hoof on each foot. The hoof is the hard keratin layer located below a horse’s leg. Horses are members of the perissodactyl family, and their hooves, although odd, play a crucial role in their survival and function.
A horse’s hoof is quite complex, and can be chalked up to two main layers: the outer layer and inside the hoof. Studying hoof anatomy has led to vast discoveries of hoof abnormalities that cause lameness in horses and abnormal hoof growth.
Read on to learn more.
The Exterior
The Sole
The sole is located under the hoof and is a protective keratin layer for the interior of a horse’s hoof. This layer is subject to friction and wears out over time. Despite being under the foot, the sole doesn’t touch the ground because of its concave shape.
Its concavity helps distribute a horse’s weight towards the sole’s borders which explains why such small hooves can support a horse’s entire weight.
Frog
The frog is also located underneath a horse’s foot, right inside the concave shape of the sole. When you lift a horse’s foot, the frog is the triangular-shaped thick ridge. It has many roles, including shock absorption, assisting with circulation, and aiding the hoof as it lands on tough terrain. The frog also contains a vast network of nerves that allow the horse to feel its feet.
Central Sulcus
The central sulcus is the collection of grooves that define the V-shape of a hoof’s frog. These grooves include the central and lateral sulci. These are sore spots because they can be either deep or shallow. Shallow sulci can harbor germs and fungi, causing infections such as thrush on a horse’s leg.
Hoof Outer Wall
Next, you’ll see the hoof’s wall, a hard keratin layer that acts as a shield for the interior of the hoof. Hooves can either be black or white. The hard layer bears the brunt of the ground each time a horse moves and supports its weight, essentially working as a shock absorber.
Hooves grow over time, and a horse owner needs to trim them periodically. That said, if the horse is constantly moving, the wall will wear itself. Ideally, a hoof wall will grow about 6-9 mm monthly.
Despite how strong the hoof’s wall is, it’s a literal Achilles heel because any damage to its interior can cause permanent damage, such as lameness in a horse.
The Laminar
This layer is directly beneath the hoof wall and supports a myriad of laminae that connect to the coffin bone. This layer can offer a bit of a give and expand as the horse moves, which helps absorb shock.
The Coronet band
From the outside, you’ll notice the joint between a horse’s leg and hoof. This is the coronary band. The coronary band works similar to the cuticle of a human’s fingers and toes, and minor injuries can cause permanent damage to a horse’s leg. This band is responsible for creating new hoof tissues.
Periople
The periople is a protective soft tissue just below the coronary band. The area looks a bit waxy and protects the hoof from excess drying. This area is essentially a transition between hoof cell creation and growth as it gives time for the hoof’s keratin layer to harden.
Bars
The bar extends from the hoof wall down towards the frog. This part supports the heel area by controlling the weight distribution as the horse moves. The bar contributes to making the sole. The bar is assisted by the angle of the bar, a soft tissue that helps support a horse’s weight by releasing the shock absorbed by the rest of the hoof.
Internal Structures
Coriums
Coriums are separated into the sole and frog coriums, which are responsible for manufacturing hoof horns. The sole corium, for instance, is a vascular structure that produces the sole, while the frog corium manufactures the frog.
Coffin Bone
The coffin bone, also known as the pedal bone, is located near the toe and encased by the hoof’s capsule. This bone’s main purpose is to give the hoof’s wall its shape. The coffin bone is covered in laminae and sole tissue and is among the most sensitive parts of a horse. Any minor damage to the coffin bone can lead to lameness.
Navicular Bone (Distal Sesamoid Bone)
The navicular bone is located just behind the coffin bone and assists the coffin bone in maintaining the hoof’s shape.
Two tendons around the hoof control a horse’s gait. The extensor tendon extends to the coffin bone and stretches the leg as a horse rests. The deep digital flexor tendon connects with the navicular bone allowing the leg to bend and flex, and the horse takes a step.
Short Pastern Bone (Middle Phalanx)
This bone rests on top of the pedal bone’s joint and beneath the long pastern bone. The bone extends towards the hoof capsule.
Digital Cushion
The digital cushion comprises of flexible tissue that expands and contracts when a horse walks to absorb shock from balancing the horse’s weight.
When a horse’s foot touches the ground, the pressure moves to the digital cushion and frog, causing the cushion to flatten. The flattening forces the walls of the hoof to expand slightly. This movement also restricts blood flow to the veins.
When a horse lifts its foot, the digital cushion expands, allowing blood to flow to the veins and causing the hoof’s walls to contract.
Lateral/Ungual Cartilage
The lateral cartilage sits just above and below the coronary band and expands to the entire roof. The lateral cartilage is a connector between the sole corium and the pedal bone and acts as shock absorbers, managing the horse’s weight as it moves.
Blood Supply
The hoof gets its blood supply from the coronary artery that branches towards the back and front of the hoof and a network of blood vessels that transverse it. Blood supply to the hoof supplies nutrients that help the hoof’s cells to regenerate and also help to regulate a horse’s hoof temperature.
Conclusion
We have learned about the two main parts of a horse hoof and how indispensable most parts are. As a horse owner, part of your work includes maintaining the hooves so that your horse stays healthy.
The most basic thing you can do is oil your horse’s hooves to keep them moisturized and healthy and then get help from a farrier to help you maintain optimal care for your horse. Products such as hydrating hoof sealants and dietary supplements can also help keep your horse healthy.