Abductor digiti minimi of foot

The abductor digiti minimi muscle of the foot is one of the intrinsic muscles located in the lateral compartment of the plantar aspect of the foot. It originates from the lateral and medial processes of the calcaneal tuberosity, the plantar aponeurosis, and the intermuscular septum separating it from the flexor digitorum brevis. The muscle runs along the lateral border of the foot and inserts into the lateral side of the base of the proximal phalanx of the fifth toe (little toe). Its primary function is to abduct and assist in flexion of the fifth toe at the metatarsophalangeal joint. The muscle is innervated by the lateral plantar nerve, a branch of the tibial nerve, with the nerve entering the muscle near its origin at the calcaneus and passing inferiorly to supply the muscle.

Origin: lateral and medial processes of the calcaneal tuberosity, the plantar aponeurosis, and the intermuscular septum separating it from the flexor digitorum brevis

Insertion: lateral side of the base of the proximal phalanx of the fifth toe

Artery: Lateral plantar artery

Nerve: Lateral plantar nerve (S1, S2)

Action: Flex and abduct the fifth toe

Antagonist: Flexor digiti minimi brevis muscle

Description: The Abductor digiti minimi (Abductor digiti quinti) lies along the lateral border of the foot, and is in relation by its medial margin with the lateral plantar vessels and nerves. It arises, by a broad origin, from the lateral process of the tuberosity of the calcaneus, from the under surface of the calcaneus between the two processes of the tuberosity, from the forepart of the medial process, from the plantar aponeurosis, and from the intermuscular septum between it and the Flexor digitorum brevis. Its tendon, after gliding over a smooth facet on the under surface of the base of the fifth metatarsal bone, is inserted, with the Flexor digiti quinti brevis, into the fibular side of the base of the first phalanx of the fifth toe.

Variations.—Slips of origin from the tuberosity at the base of the fifth metatarsal.Abductor ossis metatarsi quinti, origin external tubercle of the calcaneus, insertion into tuberosity of the fifth metatarsal bone in common with or beneath the outer margin of the plantar fascia.