Superficial peroneal nerve accessory artery: a vascular landmark in the mid-calf for ultrasound-guided ankle block

Vascular landmarks are routinely used in ultrasound-guided regional anesthesia to aid in identifying small or difficult-to-visualize nerves. In the context of ultrasound-guided ankle blocks, well-described adjacent blood vessels assist localization of all relevant nerves except the superficial peroneal nerve, for which no consistent vascular landmark is currently described in the literature. However, in our clinical practice, we have repeatedly identified a small artery in proximity to the superficial peroneal nerve in the mid-third of the leg, aiding its identification, which we believe represents the superficial peroneal nerve accessory artery (SPNAA). In this article, we provide a brief technical report on how to locate the SPNAA adjacent to the superficial peroneal nerve.