The ankle sprain, of the articulation that joins the skeleton of the leg to the foot, is one of the most common musculoskeletal injuries, both for athletes and recreational and leisure activities. Anatomically the ankle is composed of three bones namely the tibia, fibula and astragalus; the first two bones belong to the skeleton of the leg, while the astragalus is one of seven tarsal bones. Of all the injuries that may affect this articulation, the distortion is the most frequent, since this problem is found in the 75% of cases. This trauma is generally caused by excessive stress of the articulation; the typical mechanism of the distortive accident is an inversion, that consists in the internal rotation of the sole of the foot. It is not infrequent that the mechanism of the accident may be caused by an subversion, when the rotation of the sole of the foot is external; the rarer cases are when in the accident the two mechanisms coexist. When the lesion is caused by an inversion, this generally interests the talofibular front ligament, the calcaneal-fibular ligament and the posterior talofibular. On the other hand the motion injuries caused by a subversion, injure the deltoid ligament. The treatment of these lesions is initially conservative with immobilization, physio-kinesis therapy and proprioceptive recovery. When ligamentous injuries are so severe as to jeopardize the stability of the articulation you opt for a surgical reconstruction. Important, in distortive episodes, are also the cartilage injuries: in this case the treatment can be infiltrative, with application of hyaluronic acid and stem cells, or in severe cases surgical with real osteochondral transplants.