The anatomic features of the sural nerve with an emphasis on its clinical importance.

BACKGROUND: The sural nerve is formed by the union of the medial and lateral cutaneous nerves of the leg that originate from the tibial and common peroneal nerves. Operative procedures and traumatic injuries to the popliteal fossa, leg, ankle and foot place the sural nerve and its branches at risk. The aim of this study was to describe the course, variations and some clinically significant relations of the sural nerve.

METHODS: The sural nerve was dissected in 30 lower limbs (leg-ankle-foot) of 15 cadavers. The specimens were measured, drawn and photographed.

RESULTS: In 18 specimens (60%) the sural nerve originated from the union of the medial and lateral cutaneous nerves of the leg in the upper two-thirds of the leg (classic type). The union of the medial and lateral cutaneous branches was in the distal third of the leg in three specimens (10%). The lateral cutaneous nerve was absent in five (16.7%), and the medial cutaneous nerve was absent in 2 (6.7%) specimens. In two specimens (6.7%) the nerves had separate courses. The mean distance between the most prominent part of the lateral malleolus and the sural nerve was 12.76 +/- 8.79 mm. The mean distance between the tip of the lateral malleolus and sural nerve was 13.15 +/- 6.88 mm. The most common distribution of the sural nerve in the foot was to the lateral side of the fifth toe (60%), followed by the lateral two and a half toes (26.7%).

CONCLUSIONS: These described variations and measurements should be helpful for planning operative approaches that minimize the risk of sural nerve injury.