Extensor carpi radialis longus
Arms
- Origin
- Lateral supracondylar ridge of the humerus
- Insertion
- Base of the second metacarpal
- Action
- Extends the wrist and bends it toward the thumb side
- Nerve supply
- Radial nerve (C6–C7)
The wrist extensor on the thumb side, starting higher up the humerus than the other extensors. It holds the wrist back when you grip hard.