The muscular horse legs are the foundation of the horse’s movement. These incredibly strong legs are made up of bones, joints, ligaments, and muscles that are specialised to provide power, support, and balance during movement.
To help students understand the structure of the leg muscles it can be helpful to think about a series of landmarks that are easily spotted from a front or back view. The first landmark is the tuber coxa, which can be seen on both sides of the horse’s body. Another landmark is the greater trochanter, which can also be seen on both sides of the horse’s legs. The final landmark is the lesser trochanter, which is a little more hidden than the other two and can be difficult to see.
It can be helpful to break down the anatomy of a leg into its components, such as the bones, tendons, and muscles. Muscles can be divided into two categories; deep muscles and superficial muscles. Muscles that are close to the joint are called postural muscles and are responsible for supporting the joints. They have long parallel fibres and are limited in their force-length and force-velocity properties. Deep muscles are used to create power and large gymnastic movements while superficial muscles are more surface-oriented, having shorter parallel fibres and a limited force-length and force-velocity property.
Tendons are flexible bands of tissue that connect muscle to bone. They enable the muscles to move as the muscles contract and relax. The tendons in the lower leg are categorised into flexor tendons and extensor tendons. The flexor tendons flex the knee, fetlock and pastern joints while the extensor tendons straighten these joints.
The flexor and extensor tendons are derived from the parent muscles. For example, the fetlock and pastern tendons are derived from the M. fetidae longus and M. tibiae longus muscles. The stifle is a hinge joint with the knee and hock being articulated in one direction and the shin and metatarsus in the other.
Leonardo da Vinci drew a number of sketches comparing the anatomy of human and horse legs. One of these drawings, found on folio 102 recto of the Codex Leicester, compares the right horse hind leg in a lateral view with the right human leg in a frontal view. It is interesting to note that he has drawn the fetlock joint in the wrong position and also included a part of the tibia in the drawing that should not be there. He has also drawn a tibia that extends much too distally along the caudal plane for a horse. These mistakes are an excellent teaching tool for students of comparative anatomy. As with any subject, repetition is key in learning. It is also useful to find a method that suits your learning style; perhaps you work better with visual or auditory aids, for example. Creating a diagram of your own, whether it is on paper or using a photo, can be a great way to memorise the information.