Summary Flexor digitorum longus Origin Posterior surface of tibia distal to popliteal line Insertion Splits into four slips after passing through medial intermuscular septum of plantar surface of foot; these slips then insert on plantar surface of bases of 2nd - 5th distal phalanges Action Flexes toes 2 - 5; also helps in plantar flexion of ankle Innervation Tibial nerve (S2, S3) Arterial supply Muscular branch of posterior tibial artery