MR imaging of the lateral collateral ligament of the ankle.

The ankle is stabilized by three sets of ligaments: the medial collateral (deltoid) ligament, the syndesmotic ligamentous complex, and the lateral collateral ligament. Of these three, the lateral collateral ligament is the one most often injured in ankle sprains. Assessment of the extent of injury has classically relied on clinical evaluation; plain film radiographs (including stress views); and, in some acute situations, ankle arthrography and/or peroneal tenography. In this report we illustrate the use of MR in the evaluation of the lateral collateral ligament. The normal anatomy, pitfalls in image interpretation, and findings in cases of ligamentous injury are demonstrated.