This is a rare fracture of the ankle that is on the rise due to snowboarding. The snowboarder lands on the foot with the foot turned in and toes pulled up toward the face. The force of the impact is enough to break off the lateral process of the talus. This is called a Snowboarder's fracture.
The talus is the ankle bone between the heel and the lower leg bone (tibia). The lateral process is a small bump on the back of the talus. Sometimes the fragment of bone is pulled away from the talus. In severe injuries, the bone may be broken into several pieces and the nearby ligaments are also torn.