For complete anesthesia of the foot during a popliteal block for ankle and foot surgery, which additional nerve must be blocked?

For complete anesthesia of the foot during a popliteal block for ankle and foot surgery, which additional nerve must be blocked?

• A. Deep peroneal nerve
• B. Superficial peroneal nerve
• C. Sural nerve
• D. Saphenous nerve

Answer: (D)

When you perform a popliteal block, you’re anesthetizing the sciatic nerve before it branches into tibial and common peroneal divisions, so you get most of the foot’s sensation from the plantar surface (tibial) and much of the dorsal surface (common peroneal). But the medial aspect of the foot is supplied by the saphenous nerve, which comes from the femoral nerve and travels along the medial leg to the medial foot. That territory is not covered by a sciatic (popliteal) block, so to achieve complete anesthesia of the foot for ankle/foot surgery, you must block the saphenous nerve as well. The other nerves listed either are already encompassed by the sciatic block or have territories that don’t determine completion of foot anesthesia in this scenario, so they’re not the missing piece.

When you perform a popliteal block, you’re anesthetizing the sciatic nerve before it branches into tibial and common peroneal divisions, so you get most of the foot’s sensation from the plantar surface (tibial) and much of the dorsal surface (common peroneal). But the medial aspect of the foot is supplied by the saphenous nerve, which comes from the femoral nerve and travels along the medial leg to the medial foot. That territory is not covered by a sciatic (popliteal) block, so to achieve complete anesthesia of the foot for ankle/foot surgery, you must block the saphenous nerve as well. The other nerves listed either are already encompassed by the sciatic block or have territories that don’t determine completion of foot anesthesia in this scenario, so they’re not the missing piece.