Muscle
Extensor pollicis brevis
Extends the thumb MCP
High-yield
With APL, forms the anterior border of the snuffbox; de Quervain tenosynovitis.
Overview
A deep outcropping muscle extending the proximal phalanx of the thumb; forms the anterior snuffbox border with APL.
Reference facts
- Origin
- Posterior surface of the radius and interosseous membrane
- Insertion
- Base of the proximal phalanx of the thumb
- Action
- Extends the proximal phalanx and metacarpal of the thumb
- Innervation
- Posterior interosseous nerve (C7, C8)
- Blood supply
- Posterior interosseous artery
Frequently asked questions
What does the extensor pollicis brevis do?
The extensor pollicis brevis extends the proximal phalanx and metacarpal of the thumb.
What nerve innervates the extensor pollicis brevis?
The extensor pollicis brevis is innervated by the posterior interosseous nerve (C7, C8).
Where does the extensor pollicis brevis attach?
The extensor pollicis brevis originates from the posterior surface of the radius and interosseous membrane and inserts on the base of the proximal phalanx of the thumb.
What is the blood supply of the extensor pollicis brevis?
The extensor pollicis brevis is supplied by the posterior interosseous artery.