Extensor carpi radialis brevis muscle
|Extensor carpi radialis brevis|
|Posterior surface of the left forearm. Superficial muscles. The partially obscured extensor carpi radialis brevis is shown in blue.|
|Latin||musculus extensor carpi radialis brevis|
|Gray's||subject #125 452|
|Origin:||humerus at the anterior of lateral epicondyle (common extensor tendon)|
|Insertion:||base of the 3rd metacarpal|
|Nerve:||deep branch of the radial nerve|
|Action:||extensor and abductor of the hand at the wrist joint|
|Antagonist:||Flexor carpi radialis muscle|
The Extensor carpi radialis brevis is shorter and thicker than the longus, beneath which it is placed.
Origin and insertion
It arises from the lateral epicondyle of the humerus, by a tendon common to it and the three following muscles; from the radial collateral ligament of the elbow-joint; from a strong aponeurosis which covers its surface; and from the intermuscular septa between it and the adjacent muscles.
The fibers end about the middle of the forearm in a flat tendon, which is closely connected with that of the preceding muscle, and accompanies it to the wrist; it passes beneath the Abductor pollicis longus and Extensor pollicis brevis, then beneath the dorsal carpal ligament, and is inserted into the dorsal surface of the base of the third metacarpal bone on its radial side.
Under the dorsal carpal ligament the tendon lies on the back of the radius in a shallow groove called Lister's tubercle, to the ulnar side of that which lodges the tendon of the Extensor carpi radialis, longus, and separated from it by a faint ridge.
It is an extensor, and an abductor of the hand at the wrist joint. That is, it serves to manipulate the wrist so that the hand moves away from the palm and towards the thumb. The muscle, like all extensors of the forearm, can be strengthened by exercise that resist its extension. A wrist roller can be used and reverse wrist curls with dumbbells can performed.