ABSTRACT
Background: Variations in the level of terminal branching of tibial nerve into medial and lateral plantar nerve inthe posterior tarsal tunnel and its relations with posterior tibial artery has tremendous clinical importance.Tibial nerve and its terminal branches are at risk of entrapment in the posterior tarsal tunnel which is called astarsal tunnel syndrome. The results of surgeries for tarsal tunnel syndrome are variable or suboptimal. Thereason could be poor understanding of detailed anatomy of the tarsal tunnel and potential sites of nervecompression. Information regarding the same can help in endoscopic decompression surgeries for tarsal tunnelsyndrome with minimal exposure of the region to be operated. Knowledge regarding these variations can alsohelp the anesthetists to give ultrasonography guided ankle block without puncturing the blood vessels.Materials and Methods: The authors have studied topographic anatomy of tibial nerve and its terminal branchesin relation with posterior tarsal tunnel in 50 formalinized cadaveric feet. Authors divided the location of divisionof tibial nerve in posterior tarsal tunnel (PTT) into seven levels and also categorized the distance between thepoint of terminal division of tibial nerve (TN) and point of terminal division of posterior tibial artery (PTA) in fourcategories.Results and conclusion: Tibial nerve divides relatively higher than the posterior tibial artery in the PTT. Both lie inthe same compartment in the tarsal tunnel. The tibial nerve is situated deep to posterior tibial blood vessels .Theneurovascular bundle is covered by an unyielding fibrous tissue which could be the reason for the entrapment.Commonest division level of tibial nerve in PTT is level 4 which means the division lies in the range of 6mm to10mm above the distal border of flexor retinaculum. In 52% of feet the distance between point of division of TNand point of division of PTA is in a range between 0-5mm above the distal border of flexor retinaculum fallingunder category 1.