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