Aims: i) To describe the anatomy of the peroneal nerve on a tridimensional fashion, and ii) to identify an external anatomic landmark to deþne the trajectory of the nerve and its branches at the level of the proximal tibia. Material and Methods: 21 cadavers were dissected. The peroneal nerve was identiþed and followed as its branches entered the muscles of the anterior compartment of the leg. Results: The trajectory of the common peroneal nerve, and its branches was best described as a section of a circumference centered at the Gerdyñs tubercle with an average radius of 45 mm (range 41 to 49mm). In this circumference, the distance between the Gerdyñs tubercle and the common peroneal nerve at the level of the head of the þbula was equidistant to the distance between the tubercle and the most distal portion of the tibialis anterior branch of the peroneal nerve. Discussion and conclusion: Several anatomic studies describe the location of the peroneal nerve only in two dimensions and in relation to the head of the þbula. By relating the position of the peroneal nerve to the Gerdyñs tubercle, a circumferential safe zone can be easily deþned and marked preoperatively and may help avoid complications in procedures such as þbular osteotomies, high tibial osteotomies, external þxation wire placement, þxation of tibial plateau fractures, interlocking of tibial nails, and transtibial traction pin insertion.