Extensor carpi radialis brevis
Arms
Deep muscle — it lies under other muscles. X-ray makes the muscles over it see-through.
- Origin
- Lateral epicondyle of the humerus (common extensor origin)
- Insertion
- Base of the third metacarpal
- Action
- Extends the wrist and helps bend it toward the thumb side
- Nerve supply
- Radial nerve (C6–C7)
A shorter partner of the extensor carpi radialis longus, lying just under it. It keeps the wrist steady while the fingers grip.