During measurement of Wrist Ulnar Deviation, which carpal bone serves as the fulcrum?

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

Answer: (C)

When measuring wrist ulnar deviation, the capitate serves as the pivot point because it sits at the center of the proximal carpal row and forms the primary axis around which the wrist moves. As you deviate toward the ulna, the capitate stays relatively stationary while the surrounding carpal bones and the hand glide around it, providing a stable reference for the angle being measured. In practice, you place the goniometer’s axis over the capitate, with the stationary arm along the ulna and the moving arm along the midline of the third metacarpal. The other carpal bones don’t provide this stable pivot during deviation, so they aren’t used as the fulcrum.