Flexor Hallucis Longus

The Flexor Hallucis Longus is a deep posterior muscle of the leg.

Anatomical Attachments:

• Origin: Attaches to the inferior 2/3 of the posterior surface of the fibula and the interosseous membrane.
• Insertion: Attaches to the base of the distal phalanx of the great toe on the plantar surface.

Action: Flexes the great toe and assist in the plantar flexing of the foot.

Synergist: Gastrocnemius, Flexor digitorum longus, Peroneus longus and brevis, Tibialis posterior, Soleus, Plantaris.

Antagonist: Extensor hallucis longus, Extensor digitorum longus, Tibialis anterior, Peroneus tertius.

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Nerve Supply: Tibial Nerve (L5, S1, S2).

Nerve Entrapment: According to Travell and Simons, in concert with the Flexor Digitorum Longus, a Tarsal tunnel syndrome can develop.

Vascular supply: Peroneal artery.

• Primary: The pain refers to the plantar surface of the great toe and the head of the 1st metatarsal.
• Satellite or associated triggers: Tibialis posterior, the long and short extensors of the toes, the short flexors of the toes.

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Trigger Point Signs and Symptoms: The pain experienced in the great toe and the head of the 1st metatarsal joint is exacerbated during walking.

Trigger Point Activating and Perpetuating Factors: Persistent running or jogging on sloped or uneven surfaces, utilizing shoes that either do not cushion the balls of the feet or have inflexible soles, impaired mobility of the joints of the great toe.

Differential Diagnosis: Tarsal tunnel syndrome, (Segmental, Subluxation, Somatic dysfunction) L4 radiculopathy, Frostbite, Diabetic neuropathy, Polyneuropathy, Neurogenic arthropathy (Charcot’s Joint), Gout, Rheumatoid arthritis, Osteoarthritis, Bursitis, Turf toe, Paronychia (Ingrown toenail), Bunion/corns, Callus, Systemic infections or inflammation, Nutritional inadequacy, Metabolic imbalance, Toxicity, Side effects of medication.

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