The ankle joint is formed by five bones and ensures that we can move our feet up and down and to the side. It consists of upper and lower joints.
The upper joint consists of the shinbone (tibia), the fibula and the talus. The lower joint is formed by the talus, the calcaneus, and the navicular bone. Many ligaments connect these five bones together and stabilize the joint.
Twisting the ankle usually injures the ligaments that run across the outside of the ankle, while the ligaments on the inside of the joint are overstretched less often. The syndesmosis (collagen or elastic connective tissue "joint" between two bones) between the shinbone and the fibula can tear.