tarsal

tarsal, any of several short, angular bones that in humans make up the ankle and that—in animals that walk on their toes (e.g., dogs, cats) or on hoofs—are contained in the hock, lifted off the ground. The tarsals correspond to the carpal bones of the upper limb. In humans the tarsals, in combination with the metatarsal bones, form a longitudinal arch in the foot—a shape well adapted for carrying and transferring weight in bipedal locomotion.

In the human ankle there are seven tarsal bones. The talus (astragalus) articulates above with the bones of the lower leg to form the ankle joint. The other six tarsals, tightly bound together by ligaments below the talus, function as a strong weight-bearing platform. The calcaneus, or heel bone, is the largest tarsal and forms the prominence at the back of the foot. The remaining tarsals include the navicular, cuboid, and three cuneiforms. The cuboid and cuneiforms adjoin the metatarsal bones in a firm, nearly immovable joint.