Which muscle is primarily responsible for wrist extension?

Wrist extension is primarily performed by the muscles located on the posterior aspect of the forearm. The extensor digitorum muscle plays a crucial role in this action as it is responsible for extending the fingers and, by connection through the extensor expansion, it also assists in extending the wrist. It originates from the lateral epicondyle of the humerus and extends into the fingers, allowing for coordinated finger movements while simultaneously stabilizing the wrist in an extended position.

While the extensor carpi radialis is also involved in wrist extension, it primarily serves to extend and abduct the wrist rather than extend the fingers. The flexor carpi radialis and flexor digitorum profundus serve opposite functions: they are flexor muscles that act to flex the wrist and fingers, which demonstrates a distinct difference in functional role compared to the extensor muscles. Understanding these functions helps clarify why the extensor digitorum is the muscle primarily associated with wrist extension, particularly in conjunction with finger extension.