Origin: Medial process of calcaneus, flexor retinaculum, plantar aponeurosis
Insertion: Medial side of base of proximal phalanx of first digit
Nerve: Plantar nerve
Action: Abducts hallux
Antagonist: Adductor hallucis muscle
The Adductor hallucis (Adductor obliquus hallucis) arises by two heads—oblique and transverse. The oblique head is a large, thick, fleshy mass, crossing the foot obliquely and occupying the hollow space under the first second, third, and fourth metatarsal bones. It arises from the bases of the second, third, and fourth metatarsal bones, and from the sheath of the tendon of the Peronaeus longus, and is inserted, together with the lateral portion of the Flexor hallucis brevis, into the lateral side of the base of the first phalanx of the great toe. The transverse head (Transversus pedis) is a narrow, flat fasciculus which arises from the plantar metatarsophalangeal ligaments of the third, fourth, and fifth toes (sometimes only from the third and fourth), and from the transverse ligament of the metatarsus. It is inserted into the lateral side of the base of the first phalanx of the great toe, its fibers blending with the tendon of insertion of the oblique head.
Variations.—Slips to the base of the first phalanx of the second toe. Opponens hallucis,occasional slips from the adductor to the metatarsal bone of the great toe.
The Abductor, Flexor brevis, and Adductor of the great toe, like the similar muscles of the thumb, give off, at their insertions, fibrous expansions to blend with the tendons of the Extensor digitorum longus.