Extensor pollicis brevis (Musculus extensor pollicis brevis)
Educational content only — not medical advice.
Anatomy
Runs with the long abductor in the first compartment forming the radial wall of the snuffbox, inserting on the thumb proximal-phalanx base above the metacarpophalangeal joint.
Origin & insertion
Posterior radius below the long abductor origin.
Action
Extends the thumb proximal phalanx and assists its total extension.
Innervation
Radial nerve — posterior interosseous branch (C7–C8).
Clinical notes
Friction with the long abductor in the narrow canal is the same mechanism as de Quervain; frequent anatomical splitting (subcompartment) makes single first-compartment injections fail.
Related structures
Educational references
FAQ
What is the role of the Extensor pollicis brevis?
Runs with the long abductor in the first compartment forming the radial wall of the snuffbox, inserting on the thumb proximal-phalanx base above the metacarpophalangeal joint.
Why is the Extensor pollicis brevis clinically important?
Friction with the long abductor in the narrow canal is the same mechanism as de Quervain; frequent anatomical splitting (subcompartment) makes single first-compartment injections fail.
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