Lateral Head of Flexor Hallucis Brevis (Caput laterale musculi flexoris hallucis brevis)
Educational content only — not medical advice.
Anatomy
The lateral half of the short flexor of the great toe, arising with the oblique head of adductor hallucis and inserting with the lateral (fibular) sesamoid on the lateral base of the proximal phalanx. Together with the medial head it straddles the long flexor tendon and forms the flexor plate of the first metatarsophalangeal joint.
Origin & insertion
From the lateral cuneiform and cuboid with the oblique head of adductor hallucis, to the lateral base of the proximal phalanx of the great toe (with the fibular sesamoid in the tendon).
Action
Flexes the metatarsophalangeal joint of the great toe and steadies the lateral sesamoid during push-off.
Innervation
Medial plantar nerve (S1–S2).
Clinical notes
Lateral displacement of its sesamoid is graded in hallux-valgus staging (the sesamoid position on the anteroposterior radiograph). In severe forefoot deformities the whole flexor plate slips laterally, adding pronation to the great toe.
Related structures
Educational references
FAQ
What is the role of the Lateral Head of Flexor Hallucis Brevis?
The lateral half of the short flexor of the great toe, arising with the oblique head of adductor hallucis and inserting with the lateral (fibular) sesamoid on the lateral base of the proximal phalanx. Together with the medial head it straddles the long flexor tendon and forms the flexor plate of the first metatarsophalangeal joint.
Why is the Lateral Head of Flexor Hallucis Brevis clinically important?
Lateral displacement of its sesamoid is graded in hallux-valgus staging (the sesamoid position on the anteroposterior radiograph). In severe forefoot deformities the whole flexor plate slips laterally, adding pronation to the great toe.
Source & license
BodyParts3D, © The Database Center for Life Science licensed under CC Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0/). license details