peroneus

/ˌpɛrəˈniːəs/
noun
  1. Any of three muscles on the outer side of the lower leg that help move the foot and ankle.
    • She felt a strain in her peroneus after twisting her ankle.
    • Stretching the peroneus can prevent injuries in runners.
    • The peroneus longus muscle helps stabilize the ankle when walking on uneven ground.