Extensor hallucis longus
Musculus extensor hallucis longus
Also known as: EHL
A thin anterior-compartment muscle between tibialis anterior and EDL. It extends the great toe and assists dorsiflexion, and it is the classic test of the L5 myotome.
Overview
EHL arises from the middle part of the anterior surface of the fibula and the interosseous membrane, deep to tibialis anterior and EDL. It emerges between them in the lower leg. Its tendon crosses in front of the ankle, lateral to tibialis anterior, and inserts on the dorsal base of the distal phalanx of the great toe. It extends the great toe and assists dorsiflexion of the ankle and inversion. The dorsalis pedis pulse is palpated just lateral to its tendon on the dorsum of the foot.
Anatomy
- Origin
Middle part of the anterior surface of the fibula and the interosseous membrane.
- Insertion
Dorsal aspect of the base of the distal phalanx of the great toe.
- Action
Extension of the hallux; dorsiflexion of the ankle.
- Innervation
Deep fibular nerve.
- Nerve roots
L5 (L5–S1)
- Arterial supply
Anterior tibial artery.
- Relations
The dorsalis pedis artery lies lateral to its tendon on the dorsum of the foot, between the EHL and EDL tendons.
Function
- Extends the great toe
- Assists dorsiflexion of the ankle
Clinical significance
L5 radiculopathy
Weakness of great-toe extension is the most sensitive motor sign of L5 root compression, e.g. from an L4–L5 disc herniation. It is accompanied by numbness over the dorsum of the foot and the first web space.
Compiled from standard anatomy and physiology references — see the Muscular System sources. For education only; not medical advice.