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Flexor Hallucis Longus Muscle Anatomy: Origin, Insertion, Action

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Origin: Distal two-thirds of the posterior surfaces of the fibula, the adjacent interosseous membrane, the posterior intermuscular septum, and the lateral part of the fascia covering tibialis posterior
Insertion: Plantar aspect of the base of the distal phalanx of the great toe after traveling between the two sesamoids associated with the first metatarsal head
Actions: Flexion of the great toe
Innervation: Tibial nerve (L5,  S1, S2 )
Blood Supply: Branches from the posterior tibial artery
Image of the flexor hallucis longus muscle anatomy

Looking for pain and symptom information? Visit the Flexor Hallucis Longus Pain Page.

Primary Actions of the Flexor Hallucis Longus Muscle

  1. Flexion of the great toe at the interphalangeal joint

Agonists:  None

Antagonists: 

    • Extensor Hallucis Longus

Lumbricals, dorsal interossei (second, third, and fourth digits), and plantar interossei (third, fourth, and fifth digits) assist with flexion of the toes at the metatarsophalangeal joints.

2. Flexion of the great toe at the metatarsophalangeal joint

Agonists:

    • Flexor Hallucis Brevis

Antagonists:

    • Extensor Hallucis Longus
    • Extensor Hallucis Brevis

Secondary Actions of the Flexor Hallucis Longus Muscle

1. Assists with plantarflexion of the foot at the ankle

Agonists:

    • Gastrocnemius
    • Soleus

Antagonists: Tibialis Anterior

Plantaris, tibialis posterior, peroneus longus, and flexor hallucis longus also assist with plantarflexion of the foot at the ankle.