Extensor hallucis longus

The extensor hallucis longus (EHL) is a thin, spindle-shaped muscle of the anterior compartment of the leg, situated between the tibialis anterior and extensor digitorum longus.

Origin

The extensor hallucis longus muscle arises from the:

• Middle two-fourths of the anterior surface of the fibula

• Adjacent part of the interosseous membrane

Note: The muscle arises deep to the tibialis anterior and extensor digitorum longus in the proximal leg, becoming more superficial as it descends.

Insertion

Dorsal surface of the base of the distal phalanx of the great toe (hallux)

Innervation

Deep fibular (peroneal) nerve; Root value: L5 (mainly), sometimes S1

Blood Supply

Anterior tibial artery and its muscular branches

Relations

• Medial: Tibialis anterior

• Lateral: Extensor digitorum longus

• In its upper part: The extensor hallucis longus tendon lies between the tendons of tibialis anterior (medially) and extensor digitorum longus (laterally).

• In its distal part: The tendon passes beneath the superior and inferior extensor retinacula, traversing the anterior aspect of the ankle joint.

Actions

• Extends the great toe at both the metatarsophalangeal and interphalangeal joints

• Dorsiflexes the foot at the ankle joint

• Assists inversion of the foot (weakly)