Origin Lateral tibial condyle, proximal 3/4 of anterior fibula, upper part of interosseous membrane, fascia cruris, and anterior intermuscular septum Insertion Splits into 4 tendon slips after inferior extensor retinaculum, each of which insert on dorsum of middle and distal phalanges as part of extensor expansion complex Action Extend toes 2 - 5 and dorsiflexes ankle Innervation Deep peroneal nerve (L4, L5, S1) (L4, L5, S1) Arterial Supply Anterior tibial artery