Muscle
Abductor pollicis brevis
Thenar — abducts the thumb
High-yield
Thenar muscle; weak/atrophic in carpal tunnel syndrome. Recurrent (median) branch.
Overview
A superficial thenar muscle that abducts the thumb, tested in carpal tunnel syndrome. Recurrent branch of the median nerve.
Reference facts
- Origin
Flexor retinaculum, scaphoid, and trapezium
- Insertion
Lateral base of the proximal phalanx of the thumb
- Action
Abducts the thumb at the carpometacarpal and MCP joints
- Innervation
Recurrent branch of the median nerve (C8, T1)
- Blood supply
Superficial palmar branch of the radial artery