The adductor hallucis is a deep plantar muscle with an oblique head from the midfoot and a transverse head from the MTP joint capsules, inserting on the lateral great toe proximal phalanx. It is the primary driver of hallux valgus deformity, as its transverse head is tightened by narrow footwear that compresses the forefoot, progressively pulling the great toe into valgus and widening the intermetatarsal angle.
| Origin | Bases of the 2nd, 3rd, and 4th metatarsals and the fibular head of the plantar ligament; Plantar MTP joint capsules and deep transverse metatarsal ligament of toes 3, 4, and 5 |
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| Insertion | Lateral side of the base of the great toe proximal phalanx and lateral sesamoid |
| Nerve Supply | Deep branch of the lateral plantar nerve (S1, S2) |
| Blood Supply | Plantar arch |
| Actions | Adduction of the great toe toward the second toe; Assists in flexion of the great toe MCP joint; Maintains the transverse arch by pulling the first metatarsal toward the lateral toes |
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Maintaining the transverse arch and preventing excessive first metatarsal drift are its structural roles, but in hallux valgus its own tightened pull becomes a deforming force that perpetuates the deformity once initiated.
Adductor hallucis release is a component of many hallux valgus surgical procedures, performed to reduce the lateral deforming force on the great toe. The transverse head tightens from decades of narrow-toed shoe wear, creating a self-reinforcing deformity cycle. Botulinum toxin injection into the adductor hallucis has been proposed as a conservative treatment for early hallux valgus but lacks robust clinical evidence.
The adductor hallucis is not directly palpable but its tightness is assessed clinically by passive great toe abduction away from the second toe, with restricted or painful abduction indicating adductor tightness.
Progressive tightening of the adductor hallucis from narrow footwear contributing to hallux valgus deformity, addressed surgically by adductor tenotomy and first metatarsal osteotomy.
