[Topographic anatomy of the tibial nerve in the medial malleolus: application to the effect of nerve block anesthesia].

To better understand the anatomical variations and pathogeny of tarsal tunnel syndrome, the tibial nerve were dissected in 20 ankles of fresh black African cadavers. The tibial nerve located to 1.75 cm on average from the posterior side of the malleolus and to 2 cm from medial side of the calcaneus tendon. The nerve always ended according to dichotomic method. 90% cases of bifurcation were noted under the flexor retinaculum at 1 cm from the malléolo_calcaneus line; in 10% of dissections, we found proximal bifurcation at 5 cm from this line. The medal calcaneus branch which is a collateral branch of tibial nerve was constant, unique in 80% of cases and double in 20% of cases. The anatomical constatations allow a more precise anesthesia of tibial nerve block. We use constant anatomical marks formed by calcaneus tendon and internal malleolus tip. Olso we more understand the possibility of lesion of tibial nerve at the ankle during the synovites, or ossifications of flexor rétinaculum.