Dimensions of the anterior tarsal tunnel and features of the deep peroneal nerve in relation to clinical application.

BACKGROUND: The aim of this study was to demonstrate anatomical features of the anterior tarsal tunnel and the deep peroneal nerve and to discuss the importance of these structures for the anterior tarsal tunnel syndrome and some other surgical approaches to minimize the injury risk.

METHODS: Lower limbs of 18 formalin fixed cadavers were examined. The limbs showed no evidence of pathology or trauma.

RESULTS: The lateral length of the tunnel was 21.7 +/- 4.3 mm and the medial length of the tunnel was 55.0 +/- 9.0 mm. The width of the tunnel at the inferior border between the extensor hallucis longus and extensor digitorum longus tendons was 12.6 +/- 2.1 mm. The location of the deep peroneal nerve bifurcation was in the anterior tarsal tunnel in 31 specimens (86.1%) and distal to the tunnel in two specimens (5.6%). In three specimens (8.3%) there was no bifurcation because of the absence of the medial terminal branch of the deep peroneal nerve. In these three specimens, the superficial peroneal nerve distributed to the adjacent sides of the great and second toes. Bifurcation above the tunnel was not observed in our specimens. There was connection between the deep peroneal nerve and the superficial peroneal nerve in 10 specimens (27.8%) in the first interdigital space. During the observations, the presence of a fibrous band over the nerve and vessel was noted in 22 specimens (61.1%).

CONCLUSIONS: We believe that a detailed anatomic knowledge of the anterior tarsal tunnel and the deep peroneal nerve will be of help during surgical approaches to this area and the diagnosis of the problems related to the peripheral nerves on the dorsum of the foot.