Flexor digiti minimi !
The flexor digiti minimi is a small sole muscle under the fifth metatarsal that bends the little toe.
Official name: Flexor digiti minimi of foot
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What it is
A small muscle under the fifth metatarsal, with a few deep fibers that sometimes form a separate small muscle.
What it does
Bends the little toe at its base.
Key facts
- Origin
- Base of fifth metatarsal; sheath of fibularis longus tendon
- Insertion
- Base of proximal phalanx of fifth toe
- Action
- Flexes fifth toe at MTP joint
- Nerve
- Lateral plantar nerve, superficial branch (S2–S3)
- Blood supply
- Lateral plantar artery
Relations
- Superficial
- Abductor digiti minimi, which partly covers it, and the lateral band of the plantar fascia
- Deep
- Plantar surface of the fifth metatarsal
- Medial
- Third plantar interosseous
- Behind
- At its origin, the sheath of the fibularis longus tendon and the long plantar ligament near the cuboid
How to find it
It lies under the shaft of the fifth metatarsal, deep to the lateral roll of abductor digiti minimi, and is not reliably felt on its own. On MRI it lies directly against the fifth metatarsal.
On imaging
Usually not assessed on its own. On MRI or ultrasound it lies on the plantar surface of the fifth metatarsal next to abductor digiti minimi. Fatty atrophy of these lateral sole muscles on MRI points to a lesion of the lateral plantar nerve. Radiographs of this area are taken for fractures of the fifth metatarsal, not for the muscle.
Common problems
- Like the other small muscles of the foot, it can weaken with age, nerve problems or tight shoes, which can let the arch drop or the toes change shape.
Clinical notes
- It arises near the base of the fifth metatarsal, the region of avulsion and Jones fractures; it lies on the plantar side of the fracture site
- Lateral plantar nerve lesions and length-dependent neuropathies weaken it with the other lateral sole muscles; denervation shows on MRI as oedema, then fatty change
Memory aid
Third layer = the short muscles of the two end toes: flexor hallucis brevis, adductor hallucis, flexor digiti minimi brevis.
Test yourself
Think of the answer, then tap the question to see it.
What are the origin and insertion of the flexor digiti minimi of the foot?
Base of the fifth metatarsal and the sheath of the fibularis longus tendon, to the base of the fifth toe's proximal phalanx.
Which branch of which nerve supplies the flexor digiti minimi of the foot?
The superficial branch of the lateral plantar nerve.
Which three muscles make up the third layer of the sole?
Flexor hallucis brevis, adductor hallucis and flexor digiti minimi brevis: the short muscles of the two end toes.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- flexor digiti minimi pedis TA2 2682
- Official Spanish (DeCS)
- Músculo flexor del dedo pequeño del pie
- English (TA2)
- Flexor digiti minimi of foot
- Also called
- flexor digiti minimi brevis muscle of foot · flexor digiti quinti brevis
Related
Sources: Terminologia Anatomica (TA2); Anatomy, Bony Pelvis and Lower Limb, Foot Muscles.
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Representative model, for educational purposes only.
