Extensor Hallucis Longus
Leg · Lower Limb
The extensor hallucis longus is a thin muscle of the anterior compartment of the leg lying deep between the tibialis anterior and the extensor digitorum longus. It arises from the middle of the anterior surface of the fibula and the interosseous membrane, and its tendon runs down to insert on the base of the distal phalanx of the great toe. Its chief action is extension of the great toe, and because its tendon crosses in front of the ankle it also assists dorsiflexion of the ankle. It is supplied by the deep fibular (peroneal) nerve (L5, S1). The tendon is easily seen and palpated on the dorsum of the foot when the great toe is pulled upward.
Origin, Insertion, Action & Nerve
Origin
Middle of anterior surface of fibula and interosseous membrane
Insertion
Base of distal phalanx of great toe (1st Toe) (hallux)
Action
Extension of great toe (1st Toe); dorsiflexion of ankle
Nerve
Deep fibular (peroneal) nerve (L5, S1)
Attachments explained
The Extensor Hallucis Longus is defined first by where it attaches. Its origin is the more fixed anchor, usually the proximal or more stable end that stays put during contraction, while its insertion is the more mobile point that is pulled toward the origin when the muscle shortens.
Origin
Middle of anterior surface of fibula and interosseous membrane
Insertion
Base of distal phalanx of great toe (1st Toe) (hallux)
Action & function
When the Extensor Hallucis Longus contracts, it produces the following movements: Extension of great toe (1st Toe); dorsiflexion of ankle.
As part of the Leg group of the Lower Limb, it works alongside neighbouring muscles to generate smooth, coordinated movement and to stabilise the structures it acts on.
Nerve supply & clinical relevance
The Extensor Hallucis Longus receives its nerve supply from the Deep fibular (peroneal) nerve (L5, S1). This nerve carries fibres from spinal segment(s) L5, S1.
Because a muscle can only contract when its nerve is intact, injury to the Deep fibular or to its spinal roots (L5, S1) can weaken or paralyse the Extensor Hallucis Longus, impairing the movements it normally produces (extension of great toe (1st Toe)). This is why knowing the innervation is central to localising nerve lesions in clinical practice.
How to study the Extensor Hallucis Longus (the OIANS method)
Learn the extensor hallucis longus by its single, tidy job: it is the long extensor of the big toe, so its name states its action. Trace its tendon on your own foot, where it is the lone tendon running to the great toe, sitting between the broad tibialis anterior tendon medially and the fanned-out extensor digitorum longus tendons laterally. That mid-position on the dorsum of the ankle also explains its secondary role in dorsiflexion.
Tie the muscle to the deep fibular nerve and its L5 root, which is the classic root tested by great-toe extension against resistance. Because the same nerve supplies the other anterior compartment muscles, weak great-toe extension is an early clinical clue to a deep fibular nerve or L5 problem, and pairing it in memory with extensor hallucis brevis, its short accessory, keeps the two extensors of the hallux organised.
Frequently asked questions
Where is the Extensor Hallucis Longus located?
The Extensor Hallucis Longus is a muscle of the Leg group, located in the Lower Limb.
What is the origin of the Extensor Hallucis Longus?
Middle of anterior surface of fibula and interosseous membrane
What is the insertion of the Extensor Hallucis Longus?
Base of distal phalanx of great toe (1st Toe) (hallux)
What movements does the Extensor Hallucis Longus produce?
Extension of great toe (1st Toe); dorsiflexion of ankle
What nerve supplies the Extensor Hallucis Longus?
Deep fibular (peroneal) nerve (L5, S1)
Is the Extensor Hallucis Longus free to study in OIANS?
The Extensor Hallucis Longus is always free to browse. Its full origin, insertion, action and nerve details are open to everyone in the Muscle Directory. Quiz and Flashcard practice for the Lower Limb is part of the one-time Lifetime upgrade, though; only the Upper Limb decks are free to test yourself on.
Related muscles
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