AIM: Clinical examination is sometimes insufficient to assess the severity of lateral collateral ligament (LCL) sprain of the ankle, making it difficult to choose the most appropriate treatment. The aim of this study was to compare the assessment of clinical signs and the ultrasonographic findings in recent LCL sprain of the ankle. METHODS: This was a retrospective cross-sectional study. Spearman's rank correlation test and multiple regression analysis were used to assess correlations between clinical signs and type of ligament injury. Fisher's linear discriminant analysis was used to determine most contributive signs in ligament tear diagnosis. RESULTS: No single clinical sign was correlated with the severity of ligament injury as revealed by ultrasonography in the 34 patients analyzed. Careful assessment of all the usual clinical signs of severity seems to better guide the diagnosis of the presence or absence of ligament tearing. CONCLUSIONS: These results confirm the lack of correlation between clinical examination and the anatomic injury in distension or partial tearing of the anterior talofibular ligament. They raise questions about the usefulness of clinical classifications and suggest a broadening of the indications for ultrasonographic exam in ambiguous situations, particularly for athletes showing few signs of severe injury, in order to ensure optimal treatment and a faster recovery.