Challenge of the Week

Challenge of the Week / Foot & Ankle / 04.010.20

A female patient who is a ballet dancer presents for evaluation of 3 weeks of worsening posterolateral ankle pain. On examination, forced passive inversion of the foot is more bothersome than forced passive plantar flexion of the foot. Pain is elicited with resisted eversion of the foot. Which of the following anatomic structures is the most likely source of her pain?