Ultrasound guidance for a lateral approach to the sciatic nerve in the popliteal fossa.

Descriptions of the use of ultrasound for nerve location have focused on upper limb blocks. We present a case in which ultrasound imaging was used for a lateral approach to the sciatic nerve in the popliteal fossa. Ultrasound images taken proximal to the popliteal crease showed tibial and common peroneal nerves as round hyperechoic structures superficial and lateral to the tibial artery. Under direct ultrasound guidance, we placed a block needle close to the tibial nerve and confirmed its position with nerve stimulation. Injected local anaesthetic was seen on ultrasound as it spread around both tibial and common peroneal nerves.