Abductor digiti minimi muscle of foot

Origin and insertion

Abductor digiti minimi muscle originates from the plantar aponeurosis, lateral and medial processes of calcaneal tuberosity and the area between them. It courses anteriorly through the lateral part of the foot, giving off a tendon that inserts to the base of proximal phalanx of 5th digit and 5th metatarsal bone.

The part of the muscle that inserts onto the 5th metatarsal is the one originating from the lateral process of calcaneal tuberosity. These fibers can sometimes form a separate muscle called the abductor ossis metatarsi digiti quinti.

Relations

This muscle lies deep to the lateral plantar fascia and superficial to the flexor digiti minimi brevis. Lying along the lateral border of the foot, abductor digiti minimi is the most lateral muscle of the first layer. Medial to it are the flexor digiti minimi brevis muscle and the lateral plantar artery and nerve.

Innervation

Abductor digiti minimi is innervated by the lateral plantar nerve (S1, S3), a branch of the tibial nerve.

Blood supply

This muscle is supplied by the branches of lateral plantar artery; plantar metatarsal and plantar digital arteries to 5th digit.

Functions

Although called the abductor, besides abducting, this muscle is a much more powerful flexor of the fifth toe at its metatarsophalangeal joint.

Its function is analogous to that of the abductor hallucis muscle from the opposite side of the foot; it maintains the concavity of the foot by supporting the lateral longitudinal arch during walking, running and jumping.

Learn about the functions of abductor digiti minimi and other foot muscles with Kenhub’s learning materials on the topic.