The deep peroneal (fibular) nerve descends from the anterior ankle beneath the inferior extensor retinaculum to enter the dorsal foot, where it divides into a lateral branch (motor to extensor digitorum brevis and extensor hallucis brevis) and a medial branch (sensory to the first web space dorsal skin between the first and second toes). It passes under the extensor hallucis longus tendon and the dorsalis pedis artery on the dorsal foot.
Anterior tarsal tunnel syndrome is entrapment of the deep peroneal nerve under the inferior extensor retinaculum, producing dorsal foot pain and first web space sensory loss. It may be caused by tight footwear, repeated ankle dorsiflexion, or ganglion cyst compression. Tinel's sign at the dorsal ankle over the nerve reproduces the symptoms. Surgical decompression of the inferior extensor retinaculum relieves the compression. The deep peroneal nerve's lateral branch is used for electrodiagnostic assessment of EDB motor function in peroneal neuropathy localisation.
The deep peroneal nerve compressed under the inferior extensor retinaculum at the anterior ankle from tight footwear or a dorsal ganglion produces burning dorsal foot pain and first web space paresthesiae reproduced by Tinel's sign over the nerve; surgical release of the superior and inferior extensor retinaculum ligaments decompresses the nerve.
