The anterior talofibular ligament is a band of connective tissue located along the outside of the ankle joint. It originates on the fibular malleolus, the bony protrusion on the outside of the ankle joint, and then runs forward and inward to connect to the talus bone. The talus bone is an irregularly shaped bone in the foot that articulates with the tibia and fibula bones of the lower leg, forming the ankle joint. Because the anterior talofibular ligament crosses the outside or lateral aspect of the ankle joint, it is the ligament in the body most commonly sprained, typically when the foot is rolled to the outside.
Located adjacent to a number of other ligaments in the ankle, including the posterior talofibular ligament, the anterior talofibular ligament is similarly responsible for maintaining stability in ankle joint, protecting it from unpredictable outside forces. The ankle joint, the intersection of the tibia, fibula, and talus bones, is a synovial hinge joint only capable of front-to-back movement: dorsiflexion and plantarflexion. It is not intended to allow for side-to-side movement, so the ligaments protect it by absorbing lateral forces acting on the joint.
The ankle is best adapted to forward movements like walking and jogging, so performing activities like running on uneven terrain or cutting sideways while playing soccer can leave the joint vulnerable to injury from rolling or twisting. When this happens, the anterior talofibular ligament commonly takes the brunt of the impact by stretching to the point of tearing. This is known as a sprained ankle, and it has been observed that 85 percent of ankle sprains occur at the lateral, or outer, aspect of the joint. As such, the ligaments running down from the fibula bone and crossing the outside of the ankle, like the anterior and posterior talofibular ligaments, are most susceptible to injury.
Sprains to the anterior talofibular ligament can range from mild, in which the ligament is stretched beyond its normal range, to moderate, in which it may be slightly torn, to severe, in which it may be completely torn. Immediately after an injury, ecommended treatment includes rest, icing, compression, and elevation (RICE), regardless of the severity of the injury. A walking cast may be needed to support and keep weight off the joint as it heals. Depending on the severity of the sprain, it may be several weeks or several months before the individual may be allowed to return to exercise.