What muscle is known as the extensor carpi ulnaris?

The extensor carpi ulnaris is a specific muscle located in the forearm that plays a crucial role in the movement of the wrist. It is primarily responsible for extending and adducting the wrist joint, which allows for the movement of the hand toward the ulnar side or pinky side of the forearm. This muscle originates from the lateral epicondyle of the humerus and inserts into the base of the fifth metacarpal bone.

Recognizing the extensor carpi ulnaris as the correct answer emphasizes its unique functional features as an extensor muscle of the carpus (wrist) that differentiates it from other muscles in the list. The other options include muscles with different actions or locations, such as those involved in flexion or extension of the digits rather than the wrist specifically. Understanding the role and location of the extensor carpi ulnaris helps clarify its identity as an important muscle in wrist movement.