Eur J Anat, 18 (2): 81-84 (2014)

The danger zone for the plantar and calcaneal divisions of the tibial nerve - a cadaveric study

Malin D. Wijeratna¹, Nick R. Evans¹ and Philip D. Vaughan²

¹Clinical Anatomy Department, Guyâ??s, Kingsâ?? & St Thomasâ?? Medical School, London, UK and ²Norfolk & Norwich University Hospital, Norwich, Norfolk, UK

ABSTRACT In this anatomical, cadaveric study we describe a novel method of determining the point of origin of the plantar and calcaneal divisions of the tibial nerve around the tarsal tunnel, in the clinical setting, without requiring the exact path of the nerve to be known. To this end, we describe an area that arises from the midpoint of the navicular-calcaneal line (MP-NCL), which contains both nerve divisions in the majority of cases. We called this area the danger zone. We identified the size and location of this danger zone by dissecting a total of 50 cadaveric feet. We measured the distance from the origin of each nerve division to both the navicular tuberosity and the calcaneal insertion of the Achilles tendon. From these measurements we were able to calculate the distance of each division from the MP-NCL along two axes, the navicular-calcaneal line (NCL) and a line perpendicular to this crossing at the midpoint. The danger zone of the tibial nerve, around the tarsal tunnel is a 16.5 cm² (5.9 x 2.8 cm) quadrilateral area that passes posterior and proximal from the MP-NCL. This area in our study contained both the plantar and calcaneal divisions of the posterior tibial nerve in 82% of cases. Those divisions that arose outside this area (18%) occurred up to 0.5 cm anterior to the MP-NCL and 1.4 cm distal to the NCL.

Keywords: Tibial nerve, Tarsal tunnel, Origin plantar division, Origin calcaneal division medial calcaneal nerve, Medial plantar nerve, Lateral plantar nerve