Tinel's sign of the ankle involves tapping over which nerve?

• A. Posterior tibial nerve behind the medial malleolus
• B. Sural nerve near the lateral malleolus
• C. Deep peroneal nerve at the dorsum of the foot
• D. Tibial nerve at the popliteal fossa

Answer: (A)

Tinel's sign uses tapping to evoke symptoms from an irritated nerve along its path. At the ankle, the posterior tibial nerve travels just behind the medial malleolus in the tarsal tunnel. Tapping there can reproduce tingling or numbness in the plantar foot, which points to entrapment or irritation of that nerve at the ankle. The other nerves mentioned are not the typical targets for an ankle Tinel’s sign: the sural nerve near the lateral malleolus would affect lateral foot sensation, the deep peroneal nerve on the dorsum of the foot would involve the first web space, and tapping the tibial nerve in the popliteal fossa would indicate a lesion higher up, not at the ankle.