Oblique head of adductor hallucis

The oblique head of the adductor hallucis is the portion of the adductor hallucis muscle that originates from the bases of the second, third, and fourth metatarsal bones, as well as from the sheath of the fibularis longus tendon. Its muscle fibers course obliquely across the plantar aspect of the foot, converging laterally and distally to insert primarily onto the lateral side of the base of the proximal phalanx of the hallux, often via a conjoined tendon with the lateral sesamoid and fibers of the flexor hallucis brevis.

Origin:

• Bases of the 2nd, 3rd, and 4th metatarsal bones

• Sheath of the tendon of fibularis (peroneus) longus

Insertion:

• Lateral side of the base of the proximal phalanx of the great toe

• Common tendon with the transverse head (often containing a sesamoid bone)

Innervation: Deep branch of the lateral plantar nerve (S2–S3)

Blood supply: Lateral plantar artery and plantar arterial arch

Action:

• Adducts the great toe toward the second toe

• Assists flexion at the metatarsophalangeal joint

Description in Gray's: The oblique head of adductor hallucis 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.