Adductor hallucis muscle

What is Adductor hallucis muscle?

The adductor hallucis muscle is an intrinsic muscle, which has two heads. The adductor hallucis muscle is functionally a member of the medial group of plantar foot muscles, which are divided into three vertical groups: lateral, central, and medial. Nevertheless, it is anatomically situated within the foot’s central compartment.

Additionally, the muscles of the foot are divided horizontally into four layers, varying from superficial to deep. Adductor hallucis, along with flexor hallucis brevis and flexor digiti minimi brevis, make up the third layer of plantar foot muscles in that classification.

Adductor hallucis can work walking by adducting and flexing the first toe (hallux). Additionally, it helps to maintain the foot’s transverse and longitudinal arches.

Origin

The transverse and oblique heads of this muscle are the two muscular heads. The bases of the metatarsals 2 to 4 create the oblique head; the bone of the cuboid; the lateral cuneiform bone and the fibularis longus tendon.

The plantar ligaments and deep transverse metatarsal ligaments of metatarsophalangeal (MTP) joints 3 to 5 are the sources of the transverse head.

Insertion

Before inserting distally on the lateral side of the base of the first digit’s proximal phalanx, the adductor hallucis’ two heads join together. The flexor hallucis brevis tendon on the fibular sesamoid is also connected at the distal attachment point.

Relations

This muscle is located in the central compartment of the sole. It is plantar (inferior) to the tendons of the plantar interossei muscles, flexor digitorum brevis, and flexor digitorum longus. The flexor hallucis brevis attaches to the muscle mediolaterally and proximally.

The dorsal (superior) surface of the oblique head of the adductor hallucis is covered by the deep plantar arterial arch and deep branches of the lateral plantar nerve. The transverse head’s dorsal surface is then crossed by the plantar metatarsal arteries. The proper plantar digital nerves of the plantar area run across the plantar surfaces of both heads.

Innervation

The deep branch of a lateral plantar nerve (S2, S3) that originates from the tibial nerve innervates the adductor hallucis.

Blood supply

The posterior tibial artery and its branches provide this muscle with the majority of its vascular supply;

Deep branches of the medial plantar artery
Lateral plantar artery and its branches
deep plantar arch and plantar metatarsal arteries 1-4

Function

At the first metatarsophalangeal joint, the adductor hallucis muscle performs the following two actions:

It pulls the great toe toward the midline of the foot or adducts it.
It flexes the great toe with the flexor hallucis longus.
In the terminal stance phase of the gait cycle, these actions are necessary. The adductor hallucis strengthens the forefoot as the center of gravity for the body before the heel lifts by flexing and adducting the big toe. It also fixes the forefoot and stabilizes the foot arches because its transverse head is horizontal.

Clinical relevance

The foot’s transverse and longitudinal arches are supported by it. It is an essential intrinsic muscle of the foot.

The adductor hallucis may play a role in hallux valgus deformities because it pulls on the first digit’s lateral aspect. A full surgical release of the adductor hallucis distal tendon during bunionectomy has been linked to hallux varus, according to surgeons.

Assessment

By resisting flexion and adduction of the first digit, the adductor hallucis muscle can be tested.

Adductor hallucis muscle stretching

Abducting the big toe at the metatarsophalangeal joint stretches the adductor hallucis, the foot’s internal muscle.

Adductor hallucis muscle strengthening exercise

Toe adduction squeeze

Squeeze inward with some cotton buds or wedges between your toes. Your intrinsic foot muscles and toe strength will benefit from this exercise.

Toe spread out

Open the toes of your feet outward with a band. Your intrinsic foot muscles and toe strength will benefit from this exercise.

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