Variations in the branching pattern of tibial nerve in foot: a review of literature and relevant clinical anatomy.

Considerable variations have been reported regarding the branching pattern of tibial nerve (TN) close to its termination in foot. In order to comprehend the clinical anatomy of heel pain awareness of all the possible variations in relation to terminal branching pattern of TN (close to the tarsal tunnel) is essential. The present study was conducted to undertake a comprehensive review of the variations in TN branches in foot with particular emphasis on the implications for sensory distribution of these branches. Articles were searched in major online indexed databases using relevant key words. The pattern of termination of TN was noted as either trifurcation or bifurcation. Bifurcation pattern was more commonly observed and is associated with the medial calcaneal nerve (MCN) either arising high or low relative to the tarsal tunnel. The most commonly noted type of bifurcation was proximal to malleolar-calcaneal axis but within the tarsal tunnel. Across all five types of bifurcation reported in literature, the termination points of TN ranged from 3 cm proximal to 3 cm distal to malleolar-calcaneal axis and, therefore, the area beyond this region can be considered as safe zone for performing invasive procedures. MCN showed considerable variations in its origin both in trifurcation and bifurcation pattern pertaining to number of branches (one/two/three) at the point of origin. The origin of inferior calcaneal nerve was observed to be relativelyless variable as it mostly arose as a branch of lateral plantar nerve and sometimes as a direct branch from TN before termination. The frequent variation of MCN in the tarsal tunnel should be kept in mind while undertaking decompression measures in medial ankle region.