Morphometric assessment of tibial nerve and its branches around the ankle.

ABSTRACT

It is essential to understand the considerable variations in bifurcation patterns of the tibial nerve (TN) and its peripheral nerves at the level of the tarsal tunnel to prevent iatrogenic nerve injury during surgical nerve release or nerve block. A total of 16 ankles of 8 human cadavers were dissected to investigate the branching patterns of the TN, using 2 imaginary lines passing through the tip of the medial malleolus (MM) as reference lines. Bifurcation patterns and detailed information on the relative locations of the medial plantar, lateral plantar, medial calcaneal, and inferior calcaneal nerves to the reference lines were recorded. The most common bifurcation pattern was Type 1 in 12 ankles (75%), followed by Type 2 in 2 ankles (13%). One medial calcaneal nerve (MCN) was seen in 11 (69%) specimens and 2 MCN branches were seen in 5 (31%) specimen. 88% of the MCN branches bifurcated from the TN, whereas 6% originated from both TN and lateral plantar nerve (LPN). At the level of the tip of the MM, 2 of 7 parameters showed statistically significant difference between both sexes (P < .05). There was a statistically significant difference between left and right ankles in 2 of 7 measurements (P < .05). Further morphometric analysis of the width, distance, and angle between the TN branches and the tip of MM showed a highly variable nature of the location of the peripheral nerve branches.