Horses do not possess knees in the same way humans do, a common point of confusion. While a horse’s anatomy includes joints that allow for bending and movement similar to our knees, these structures are distinct. This article clarifies the terminology and function of these “knee-like” joints.
Dispelling the “Knee” Myth
Horses do not have a joint anatomically equivalent to a human knee. The human knee is a hinge joint connecting the thigh bone (femur) to the shin bone (tibia). In horses, the joint homologous to the human knee is called the “stifle,” located only in the hind legs. What people commonly refer to as a horse’s “knee” in its front leg is actually homologous to a human wrist. The joint in the hind leg often mistaken for a knee is homologous to a human ankle.
The Carpus: Horse’s Front Leg Joint
The carpus, commonly called the “knee” in horses, is located in the front leg, positioned similarly to where a human’s wrist would be. This complex joint is comprised of multiple small bones arranged in two rows, typically seven or eight carpal bones. The carpus contains three main articulations: the radiocarpal, middle carpal, and carpometacarpal joints. It functions to absorb concussion and facilitate the flexion and extension of the lower limb, enabling the horse’s movement and agility.
The Hock: Horse’s Hind Leg Joint
In the horse’s hind leg, the hock is anatomically similar to a human ankle. It connects the tibia (the main bone of the gaskin) to the cannon bone and is composed of multiple bones and four main joints. The largest and most active is the tibiotarsal joint, which allows most of its movement. The hock plays a significant role in propulsion, power, and shock absorption, enabling a horse to gallop, jump, and perform complex movements.
Implications for Horse Health and Performance
Understanding the correct anatomy of the carpus and hock is important for maintaining a horse’s soundness and athletic performance. These joints endure considerable stress during a horse’s daily activities, especially in athletic disciplines. Injuries or conditions affecting these joints can impair a horse’s ability to move and perform, potentially leading to lameness or reduced mobility. Proper care, including balanced nutrition, appropriate exercise, and veterinary attention, helps support the health and longevity of these structures. Prioritizing joint health from a young age can help prevent issues like osteoarthritis and support a horse’s career.