Hock (anatomy)

The hock, or gambrel, is the joint between the tarsal bones and tibia of a digitigrade or unguligrade quadrupedal mammal, such as a horse, cat, or dog. This joint may include articulations between tarsal bones and the fibula in some species (such as cats), while in others the fibula has been greatly reduced and is only found as a vestigial remnant fused to the distal portion of the tibia (as in horses). It is the anatomical homologue of the ankle of the human foot. While homologous joints occur in other tetrapods, the term is generally restricted to mammals, particularly long-legged domesticated species. Although the tarsus refers specifically to the bones and joints of the hock, most people working with horses refer to the hock in such a way to include the bones, joints, and soft tissue of the area. The hock is especially important in equine anatomy, due to the great strain it receives when the horse is worked. Jumping, and movements that require collection, are some of the more stressful activities. In the horse, the hock consists of multiple joints, namely: Tibiotarsal or tarsocrural joint Proximal intertarsal joint or talocalcanealcentroquartal joint Distal intertarsal joint or centrodistal joint Tarsometatarsal joint Talocalcaneal joint In the horse, the hock consists of the following bones: Talus Calcaneus Central tarsal bone Fused 1st and 2nd tarsal bone 3rd tarsal bone 4th tarsal bone 2nd metatarsal bone 3rd metatarsal bone 4th metatarsal bone Horses may suffer from "capped hock", which is caused by the creation of a false bursa, a synovial sac beneath the skin. Capped hock is usually caused by trauma such as kicking or slipping when attempting to stand. In the absence of a wound, it does not require immediate veterinary attention and is usually only of cosmetic significance. On the other hand, a wound into the calcanean bursa is a serious problem. A capped hock is extremely unlikely to be a cause of lameness, even if severe.