Extensor carpi radialis muscle

There are two extensor carpi radialis muscles, both of them are responsible for extending and abducting the wrist:
 * Extensor carpi radialis longus muscle
 * Extensor carpi radialis brevis muscle

The difference is the the extensor carpi radialis brevis muscle is a shorter and thicker and sits underneath the extensor carpi radialis longus muscle. The longus muscle connects to the second metacarpal bone while the brevis connects to the third metacarpal bone.