Name

# Extensor Digitorum Longus

Pronunciation

(eks-TEN-sor dij-I-TOR-um LONG-gus)

Origin/Proximal Attachment

Upper ¾’s of anterior-medial surface of fibula

Adjacent anterior surface of interosseous membrane

middle & distal phalanxes of crural fascia

Lateral condyle of tibia

Anterior crural intermuscular septum

Septum between it & tibialis anterior

Insertion/Distal Attachment

Dorsal surface of bases of foot

(At the MTP joints the tendons to the 2nd, 3rd & 4th toes are each joined on the lateral side by a tendon of the extensor digitorum brevis)

Action/Relevance

Extends the lateral 4 toes

Weakly dorsiflexes & everts 2nd-5th toes (via 4 tendons & a fibrous expansion) synergistically with tibialis anterior & extensor Hallucis longus

Innervation

Deep peroneal nerve (L4, 5,S1)

Notes

Pennate muscle

In upper part of low leg the anterior tibial vessels & deep peroneal nerve lie between the muscle & tibialis anterior

At a lower level extensor Hallucis longus also comes between them

It becomes tendinous at about the same level as tibialis anterior

The tendon passes behind the superior extensor retinaculum & within a loop of the inferior retinaculum with peroneus tertius

Tendon divides into 4 slips