Innervation Motor leg tibialis anterior extensor digitorum longus peroneus tertius extensor hallucis longus foot lateral terminal branch: extensor digitorum brevis and extensor hallucis brevis Sensory articular branch to the ankle joint medial terminal branch: 1st dorsal webspace Reflex none Origin CNS origin is derived from the common peroneal (fibular) nerve, which is made of the dorsal branches of L4 and L5 Course Bifurcation of the common peroneal nerve begins at the bifurcation of the common peroneal nerve Interosseous membrane passes deep to extensor digitorum longus along anterior surface of interosseous membrane Crosses anterior tibial artery runs initially lateral to the anterior tibial artery, but crosses over to run on the medial side by the time it reaches the ankle joint Anterior Tarsal Tunnel the deep peroneal nerve passes through the anterior tarsal tunnel Terminal branches Lateral terminal branch Medial terminal branch Injury & Clinical Conditions Damage to this nerve results in foot drop most common isolated mononeuropathy of the lower extremity systemic causes of injury lower motor neuron disease diabetes ischemia inflammatory conditions iatragenic injuries TKA surgical approach