Branching pattern of tibial nerve in the tarsal tunnel - a cadaveric study

Abstract

Background and aims: Tibial nerve is the larger terminal branch of sciatic nerve, ends by dividing into medial and lateral plantar nerves beneath the flexor retinaculum [Tarsal tunnel]. The level of bifurcation of the tibial nerve is differently quoted in text books and articles. The aim of the present study is to localize the level of bifurcation of tibial nerve. Materials and methods: 50 lower limbs from 25 cadavers available in the Department of anatomy, M.S. Ramaiah medical college and Bangalore medical college were used for the study. A reference line of 1 cm width ‘Medio Malleolar Calcaneal axis’ [MMC axis] made with OHP sheet was placed from tip of the medial malleolus of tibia to the medial tubercle of calcaneus and used as grid to classify the level of bifurcation of tibial nerve into 3 types. Type I, II, III represented the bifurcation proximal to, deep to and distal to this axis respectively. Results: Tibial nerve bifurcation was found to be type I in 92%, type II in 6%, type III in 2% of specimens. Most of the cases [32.6%] bifurcated between 5.1 to 10 mm proximal to MMC axis. The median distance of medial plantar nerve from medial malleolus was 21.28mm on left side and 20.735mm on right side. The mean of lateral plantar nerve from medial tubercle of calcaneus was 29.61mm on left side, and 28.6mm on right side. Conclusion: Detailed anatomical knowledge of tibial nerve prevents the damage to tibial nerve during various surgical procedures like fixation of fractures with external nailing of tarsal bones, medial displacement osteotomies and in tarsal tunnel surgeries.

The bifurcation and topography of the posterior tibial artery within the tarsal tunnel

“…This relaxed ankle position is consistent with that of surgical procedures, although ensuring this position is consistent with that of 135° angle will warrant that results from this study are applied as accurately as possible. Throughout the literature, the angle of the ankle was presented as either 90° [ 17 , 23 , 35 ], or was not reported at all [ 9 , 24 , 32 ]. As seen in our results, the location of PTA bifurcation varies significantly between ankle angles, suggesting that the location of this vascular structure is dependent on the angle in which the ankle is situated.…”

“…The role that the PTA plays in both the formation and exacerbation of TTS is persistent and prominent in current literature [ 4 , 16 , 18 , 20 , 26 , 29 ]. Despite this, literature regarding the anatomical pattern and pathway of the PTA is sparse [ 9 , 17 , 23 , 32 , 33 , 35 ], especially when compared to that of the TN [ 8 , 9 , 14 , 17 , 24 , 27 , 31 ]. In addition, the few studies that do investigate this vascular structure [ 9 , 17 , 23 , 32 , 33 , 35 ] demonstrate various inconsistencies in their use of specific bony landmarks and reference lines, the exact measurement parameters, presentation of results and explanations of dissection protocols and techniques.…”

“…Iatrogenic injury to the posterior tibial artery (PTA) during both conservative and surgical treatment of TTS can potentially lead to compression of the TN and further exacerbation of this entrapment neuropathy [ 4 , 16 , 18 , 26 ]. Despite the prominent involvement of this vascular structure in the exacerbation of TTS, literature regarding the general topography of the PTA within the TT is limited [ 9 , 17 , 23 , 32 , 33 , 35 ], especially when compared to that of the TN [ 8 , 9 , 14 , 17 , 24 , 27 , 31 ]. In addition, no published study (to the authors’ knowledge) has considered the length of the foot, and its effect on the location of PTA within the TT.…”