What serves as the axis for radial and ulnar deviation in the wrist?

• A. Scaphoid
• B. Capitate
• C. Lunate
• D. Triquetrum

Answer: (B)

The capitate bone serves as the axis for radial and ulnar deviation in the wrist because it is the largest carpal bone and located centrally in the wrist joint. The movements of radial deviation (movement toward the thumb side) and ulnar deviation (movement toward the pinky side) occur around this axial point. The capitate's position allows for effective movement in both directions, making it integral in wrist mechanics.

In the context of wrist anatomy, while the scaphoid and triquetrum are important bones, they do not serve as the axis for these specific movements. The scaphoid is also involved in the wrist's mechanics, but it is not central enough to provide the primary axis for deviation motions. The lunate, although it articulates with other carpal bones, does not play the central role that the capitate does in this regard. Thus, the capitate is the foundational bone around which these critical movements revolve.