The sural nerve formed by the medial and lateral sural cutaneous nerves descends along the posterior lateral leg and passes posterior and inferior to the lateral malleolus at the ankle, running with the small saphenous vein. At the ankle it gives calcaneal branches to the posterior lateral heel and then continues as the lateral dorsal cutaneous nerve of the foot supplying the dorsal lateral foot and the dorsal lateral fifth toe. The nerve is 2-4 mm in diameter at the ankle and accessible for peripheral nerve stimulation.
The sural nerve at the ankle is the most commonly harvested donor nerve for peripheral nerve grafting, accessible through small transverse incisions along the lateral calf and lateral malleolus. Its harvest provides 30-40 cm of sensory nerve graft with a calibre well-matched for facial and digital nerve reconstruction. The nerve is blocked at the lateral malleolus for lateral forefoot and heel anaesthesia. In ankle surgery, the sural nerve at the lateral malleolus is at risk in lateral approach incisions for fibular fixation and for lateral ankle ligament reconstruction.
The sural nerve running posterior to the lateral malleolus is at risk in lateral ankle incisions for fibular plating, peroneal tendon surgery, and lateral ankle ligament reconstruction; its injury produces lateral foot numbness and potentially painful neuroma managed by nerve injection and if persistent by excision with nerve end relocation.
