Extensor Carpi Radialis Brevis
|Origin||Lateral epicondyle of the humerus.|
|Insertion||Dorsal surface of base of the second metacarpal.|
|Action||Straightens and pulls back the wrist.|
Extensor carpi radialis brevis is framed above by extensor carpi radialis longus. It seems to form a tail on the larger muscle on the radial side of the arm.
It is framed below by the thumb group of the forearm, but its prominent tendon reappears at the wrist. This tendon is responsible for the squarish shape of the lower forearm, and the angle formed here can be extrapolated back up to the muscle to form a useful, block-like mass conception of this side of the forearm.