Why a ankle MRI?
The ankle is a small joint with a lot going on — three bones, multiple ligament complexes, the Achilles tendon, the peroneal tendons, the tibialis posterior tendon, and a dome of articular cartilage on the talus.
X-rays show bone. MRI shows everything else. If pain or swelling has lasted more than a few weeks, or if a sprain has not settled the way you would expect, MRI is normally the test that gives a clear answer.