Occult talus fractures can be easily misdiagnosed as simple ankle sprains, resulting in painful nonunion, arthrosis, avascular necrosis, and long-term disability. We present a case of ankle injury with medial talar fracture that was negative on plain radiography but was diagnosed with sonography. Sonography is a valuable tool in screening ankle sprains and may assist clinicians in diagnosing the nature of ankle injury, thus guiding the most appropriate therapeutic strategy.