Abductor Digiti Minimi (Foot)
Foot · Lower Limb
The abductor digiti minimi of the foot is the lateral muscle of the first plantar layer, forming the fleshy outer border of the sole. It arises from both the lateral and medial processes of the calcaneal tuberosity and from the plantar aponeurosis, and its tendon passes forward to the lateral side of the base of the proximal phalanx of the fifth toe. It abducts and helps flex the fifth toe at the metatarsophalangeal joint, and its long course along the lateral arch contributes to support of the lateral border of the foot. It is supplied by the lateral plantar nerve (S2-S3), the sole's equivalent of the ulnar nerve. It is the most lateral of the three first-layer muscles that span from the heel toward the toes.
Origin, Insertion, Action & Nerve
Origin
Lateral and medial processes of the calcaneal tuberosity and plantar aponeurosis
Insertion
Lateral side of the base of the proximal phalanx of the fifth toe
Action
Abducts and flexes the fifth toe at the metatarsophalangeal joint
Nerve
Lateral plantar nerve (S2–S3)
Attachments explained
The Abductor Digiti Minimi (Foot) is defined first by where it attaches. Its origin is the more fixed anchor, usually the proximal or more stable end that stays put during contraction, while its insertion is the more mobile point that is pulled toward the origin when the muscle shortens.
Origin
Lateral and medial processes of the calcaneal tuberosity and plantar aponeurosis
Insertion
Lateral side of the base of the proximal phalanx of the fifth toe
Action & function
When the Abductor Digiti Minimi (Foot) contracts, it produces the following movement: Abducts and flexes the fifth toe at the metatarsophalangeal joint.
As part of the Foot group of the Lower Limb, it works alongside neighbouring muscles to generate smooth, coordinated movement and to stabilise the structures it acts on.
Nerve supply & clinical relevance
The Abductor Digiti Minimi (Foot) receives its nerve supply from the Lateral plantar nerve (S2–S3). This nerve carries fibres from spinal segment(s) S2, S3.
Because a muscle can only contract when its nerve is intact, injury to the Lateral plantar nerve or to its spinal roots (S2, S3) can weaken or paralyse the Abductor Digiti Minimi (Foot), impairing the movements it normally produces (abducts and flexes the fifth toe at the metatarsophalangeal joint). This is why knowing the innervation is central to localising nerve lesions in clinical practice.
How to study the Abductor Digiti Minimi (Foot) (the OIANS method)
Anchor this muscle as the lateral bookend of the first plantar layer, mirroring abductor hallucis on the opposite border. Both run from the calcaneal tuberosity to the base of a border toe's proximal phalanx, so the parallel of medial abductor for the great toe and lateral abductor for the little toe makes their actions easy to recall together.
Fix its lateral plantar nerve supply by comparison with the hand, where the ulnar nerve serves the little-finger muscles. Because the lateral plantar nerve is the sole's ulnar counterpart, expecting it to drive the little-toe abductor helps you predict the innervation of the whole hypothenar-like group along the foot's lateral edge.
Frequently asked questions
Where is the Abductor Digiti Minimi (Foot) located?
The Abductor Digiti Minimi (Foot) is a muscle of the Foot group, located in the Lower Limb.
What is the origin of the Abductor Digiti Minimi (Foot)?
Lateral and medial processes of the calcaneal tuberosity and plantar aponeurosis
What is the insertion of the Abductor Digiti Minimi (Foot)?
Lateral side of the base of the proximal phalanx of the fifth toe
What movements does the Abductor Digiti Minimi (Foot) produce?
Abducts and flexes the fifth toe at the metatarsophalangeal joint
What nerve supplies the Abductor Digiti Minimi (Foot)?
Lateral plantar nerve (S2–S3)
Is the Abductor Digiti Minimi (Foot) free to study in OIANS?
The Abductor Digiti Minimi (Foot) is always free to browse. Its full origin, insertion, action and nerve details are open to everyone in the Muscle Directory. Quiz and Flashcard practice for the Lower Limb is part of the one-time Lifetime upgrade, though; only the Upper Limb decks are free to test yourself on.
Related muscles
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