The ankle has the highest incidence of sports injuries. The Tarsus, or ankle, consists of seven bones located between the lower leg bones and the metatarsus. The largest tarsal bone is the Calcaneus. It gives the heel it's shape and supports the talus. The function of the calcaneus is to provide a level attachment for the calf muscle and to lead the body weight to the ground. The Talus is superior to all of the tarsal bones. It sits on the calcaneus over a bony projection called the sustentaculum tali and connects the leg to the foot. The talus consists of a body, neck and head and is responsible for inversion and eversion as well as dorsiflexion and plantarflexion. The navicular bone is positioned on top of the talus and on the medial side of the foot and is attached to the three cuneiform bones. The cuneiform bones are located between the navicular and the base of the three metatarsals on the medial side of the foot. The last bone is the Cuboid bone. Is is positioned on the lateral side of the foot. It sits below the calcaneus and anteriorly with the fourth and fifth metatarsals. .
The ankle consists of many ligaments that connect the bones. These ligaments support the bony structure of the ankle and include the articular capsule, three lateral ligaments and the medial or deltoid ligament. The three lateral ligaments are the anterior talofibular, the posterior talofibular and the calcaneofibular. The anterior talofibular's primary function is to restrain anterior displacement of the talus. The calcaneofibular is to restrain inversion of the calcaneus. The Posterior talofibular is to restrain posterior displacement of the talus. The medial ligament, the deltoid, is a triangular shaped ligament that attaches to the talus, calcaneus and navicular bones. Its primary function is to resist foot eversion. It also prevents abduction of the ankle and subtalar joint and prevents pronation and anterior displacement of the talus.