Tibial nerve branching in the tarsal tunnel.

To provide an anatomical basis for diagnosis and treatment of the tarsal tunnel syndrome, the relationship of the tibial nerve to the tarsal tunnel was investigated in 31 feet of 20 cadavers. The bifurcation into medial and lateral plantar nerves occurred within 1 cm of the malleolar-calcaneal axis in 90% of the feet. Seven of 11 bilateral specimens were bilaterally symmetrical in the bifurcation location; three varied within 1 cm between sides; and in the fourth cadaver, one side bifurcated at 3 cm and the other at 5 cm proximal to the axis. The calcaneal nerve showed great variability; in seven cadavers, it arose within, in eight cadavers proximal to, and in five cadavers there were multiple branches arising both proximal to and within the tarsal tunnel.