Foot and toe surgery can be successfully performed with an ankle block. There are five peripheral nerves that innervate the foot: Tibial, Deep peroneal, superficial peroneal, sural, and saphenous. They all derived from the sciatic nerve with the exception of the saphenous which is derived from the femoral nerve. At the ankle, the 2 nerves that lie deep are the tibial and deep peroneal, and the nerves lying superficially are the superficial peroneal, sural and saphenous.
- Tibial nerve: (Motor: flexors of the foot; Sensory: sole of foot) Located posterior to the posterior tibial artery. The nerve is blocked by the needle contacting the medial malleolus, slight withdrawal and injection of 3-5 ml of local anesthetic.
- Deep peroneal: (Motor: extensors of foot; Sensory: first web space) Located lateral to the dorsalis pedis artery. It is blocked by inserting the needle lateral to the artery and contacting bone. After slight withdrawal of the needle, inject 2-4 ml of local anesthetic.
- Superficial peroneal: (Motor: extensors of foot; Sensory: dorsum of foot) Located between peroneus brevis and extensor digitorum longus. It is blocked by injecting a subcutaneous wheal of local anesthetics, approximately 5 ml, from the anterior border of the tibia to the lateral malleolus.
- Sural nerve: (Motor: none; Sensory: lateral foot) Located between the lateral malleolus and calcaneus. To block, insert the needle between the achilles tendon and the lateral malleolus and subcutaneously inject approximately 5 ml of local anesthetic along this course.
- Saphenous nerve: (Motor: none; Sensory: medial leg & foot) Located adjacent to the saphenous vein, and lateral to the medial malleolus. To block, injected a subcutaneous wheal of local anesthetic, approximately 5 ml, directing it posteriorly from the tibial to the medial malleollus.