Dynamic high-resolution US of ankle and midfoot ligaments: normal anatomic structure and imaging technique

The ankle is the most frequently injured major joint in the body, and ankle sprains are frequently encountered in individuals playing football, basketball, and other team sports, in addition to occurring in the general population. Imaging plays a crucial role in the evaluation of ankle ligaments. Magnetic resonance imaging has been proven to provide excellent evaluation of ligaments around the ankle, with the ability to show associated intraarticular abnormalities, joint effusion, and bone marrow edema. Ultrasonography (US) performed with high-resolution broadband linear-array probes has become increasingly important in the assessment of ligaments around the ankle because it is low cost, fast, readily available, and free of ionizing radiation. US can provide a detailed depiction of normal anatomic structures and is effective for evaluating ligament integrity. In addition, US allows the performance of dynamic maneuvers, which may contribute to increased visibility of normal ligaments and improved detection of tears. In this article, the authors describe the US techniques for evaluation of the ankle and midfoot ligaments and include a brief review of the literature related to their basic anatomic structures and US of these structures. Short video clips showing dynamic maneuvers and dynamic real-time US of ankle and midfoot structures and their principal pathologic patterns are included as supplemental material. Use of a standardized imaging technique may help reduce the intrinsic operator dependence of US. Online supplemental material is available for this article.