What is ulnar deviation?

Ulnar deviation refers specifically to the movement of the wrist joint that brings the hand closer to the little finger, which is known as the ulnar side of the forearm. This action occurs primarily at the wrist and involves bending the wrist medially. The muscle groups responsible for this movement primarily include the flexor and extensor carpi ulnaris, which facilitate the hand's movement toward the ulnar side.

The other options describe different movements or incorrectly specify the direction. For instance, movement towards the thumb is known as radial deviation, while the description of joint action moving towards the wrist doesn’t accurately define ulnar deviation. Similarly, the mention of diagonal movement does not align with the standard anatomical terms used to describe hand and wrist positions. Therefore, the correct identification of ulnar deviation as the movement towards the little finger highlights the precise nature of this wrist action.