Extensor carpi radialis brevis muscle

The extensor carpi radialis brevis muscle is a muscle of the wrist that connects that humerus at the elbow to the hand. It acts to Abduction (Anatomy)|abduct and extend the hand.

The extensor carpi brevis longus muscle works in conjunction with the extensor carpi radialis longus muscle, a longer and thinner muscle located above it.

Origin
The extensor carpi radialis brevis muscle originates from the humerus, on the anterior aspect of the lateral epicondyle.

Insertion
The extensor carpi radialis brevis muscle inserts at the posterior base of the third metacarpal bone, the metacarpal bone of the middle finger.

Innervation
The extensor carpi radialis brevis muscle is innervated by the posterior interosseous nerve, C7 and C8.

Word origin

 * extensor, because the muscle extends the wrist when contracted.
 * carpi, meaning wrist, referring to the insertion point.
 * radialis, meaning bone, because it is on the side of the arm with the radius, distinguishing it from the extensor carpi ulnaris muscle.
 * brevis, meaning short, differentiates it from the extensor carpi radialis longus muscle, which is longer and performs a similar action.