The anterior talofibular ligament of the ankle, described as the lateral sprain ligament by Paturet as early as 1951, is the first to be affected by a forced varus injury mechanism. Despite its codified therapeutic management, ankle sprains remain a public health problem due to their frequency and recurrence. For this reason, many exploratory and surgical techniques and even preventive techniques have been developed in recent years to improve its prognosis. The diagnosis is particularly clinical, but also radiological.Functional treatment represents the basis of therapeutic management and surgical repair is reserved for certain cases such as chronic laxity, recurrent sprains, chronic instability, or in high-level athletes. The existence of numerous anatomical varieties in the ligaments of the ankle requires practitioners to have a thorough knowledge of this region.In this book, we propose an anatomical, radiological and clinical study of the first structure affected by this pathology; the anterior talofibular ligament.