Ankle Blocks

Abstract

For successful anesthesia of the foot using an ankle block, there should be blockade of the five nerves that innervate the foot: four from the sciatic nerve (posterior tibial, deep peroneal, superficial peroneal, and sural) and one from the femoral nerve (saphenous). If a proximal sciatic nerve block has been performed and an additional block of the saphenous nerve is required, an isolated block of the saphenous nerve, either anterior and medial to the medial malleolus or at or above the knee, can be performed. Traditionally, ankle blocks have been performed with landmark-based approaches; with the use of ultrasound imaging, it is now possible to anesthetize the deeper nerves (posterior tibial and deep peroneal nerves) under ultrasound guidance. This allows more precise localization of the nerve, reducing local anesthetic volume and avoiding intravascular and intraneural injection. This chapter describes landmark techniques for the blockade of the five nerves, as well as ultrasound-guided technique for the posterior tibial and deep peroneal nerves.