[Surgical anatomy of the sural nerve].
The sural nerve is generally used as a graft in nervous reconstructions due to its easy access and minimal sequelae after its withdrawal. Although this nerve presents a constancy in its topographical localization, anatomical variations are frequent. Thus, trying to determine the formation pattern of the sural nerve complex, 38 legs from 19 cadaveres were dissected. The data obtained differ from those of the literature as to the frequency of the occurrence of the two classically known patter (pattern I and II). Besides, it was possible to identify two other paterns (pattern III and IV) of the sural nerve formation not yet described The cutaneous nerve and the comunicating peroneal nerve were found in 21% of the cases. In the literature, the frequency is of 65.8% to 80%. Pattern II, where the sural nerve is originated from the medial sural cutaneous nerve, was identified in 52.6% of cases, while in the literature its frequency is of 20 to 34.2%. Pattern III, not yet described in the literature, had the sural nerve coming from the junction between the medial sural cutaneous nerve and the lateral sural cutaneous one, with a frequency of 21% of the cases. Pattern IV, also not yet described in the literature, had the sural nerve originated from the common fibular nerve in 5.2% of patients. It was also possible to identify in the sample the presence of the lateral sural cutaneous nerve (branch of the common fibular nerve) and of the peroneal communicating nerve (branch of the lateral sural cutaneous nerve) with anatomical characteristics indicating them as an alternative source of nerve grafts.