Tarsal tunnel syndrome compression involves which nerve?

• A. Saphenous nerve
• B. Posterior tibial nerve
• C. Sural nerve
• D. Common peroneal nerve

Answer: (B)

Tarsal tunnel syndrome involves compression of the posterior tibial nerve as it passes under the flexor retinaculum behind the medial malleolus, where it gives rise to the plantar nerves. This nerve supplies sensation to the plantar surface of the foot and motor innervation to many intrinsic foot muscles; compression here causes numbness, burning, and sometimes weakness in the sole and toes. The other nerves listed do not travel through the tarsal tunnel: the saphenous nerve is a cutaneous branch along the medial leg, the sural nerve runs laterally near the heel, and the common peroneal nerve courses around the fibular neck.