Extensor Carpi Ulnaris
| Pronuncation | |
| Derivation | |
| Origin | Lateral epicondyle of the humerus and dorsal surface of the ulna. |
| Insertion | Dorsal surface of fifth metacarpal. |
| Action | Extends wrist and bends it sideways towards the ulna. |
Extensor carpi ulnaris is the last long muscle in the extensor group counting around from the brachioradialis to the ulna. Its form appears from under extensor digitorum, curves around the ulna, and follows it down to the wrist and metacarpals. There is a depressed line between this muscle and the ulna.
Its tendon lies in a shallow groove on the dorsal surface of the ulna, raising the ridge of the bone and forming the corner of a useful, box-shaped mass conception of the forearm on this side of the wrist. (Compare to extensor carpi radialis brevis.)