The deep peroneal nerve in the foot and ankle: an anatomic study.

Injury to the deep peroneal nerve in the foot and ankle may result from trauma, repetitive mechanical irritation, or iatrogenic harm. The nerve is most susceptible to injury along its more distal anatomic course. Dissection of 17 cadaver specimens was undertaken to describe the course of the deep peroneal nerve and quantify its branch patterns. In the distal one third of the leg, the nerve was located superficial to the anterior tibial artery between the tibialis anterior and extensor hallucis longus muscles. Typically, the nerve crossed deep to the extensor hallucis longus tendon to enter the interval between the extensor hallucis longus and extensor digitorum longus at an average distance of 12.5 mm proximal to the ankle. A proximal bifurcation was usually present at an average distance of 12.4 mm distal to the mortise. The lateral terminal branch penetrated the deep surface of the extensor digitorum brevis to provide motor innervation. The medial terminal branch passed over the talonavicular joint capsule, and coursed an average of 2.9 mm lateral to the first tarsometatarsal joint. Within the forefoot, it passed deep to the extensor hallucis brevis tendon, bifurcated in the midmetatarsal region, and then arborized, supplying sensibility to the first toe interspace and the adjacent sides of the first and second toes.