Three-dimensional carpal kinematics of trotting horses.
Authors: Clayton H M, Sha D, Stick J A, Mullineaux D R
Journal: Equine veterinary journal
Summary
# Editorial Summary: Three-dimensional carpal kinematics of trotting horses Understanding how the carpus actually moves in three dimensions—rather than assuming it functions purely in the sagittal plane—provides essential baseline data for interpreting both normal function and pathological changes in this high-stress joint. Clayton and colleagues used high-speed videography (120 Hz) and six-camera motion capture to track bone-fixed markers on the radius and third metacarpal bone in three healthy horses during trotting, then calculated precise joint angles using spatial attitude mathematics. The findings revealed consistent patterns across individuals: the carpus extends and internally rotates during late stance to achieve a close-packed position, then initiates flexion in late stance that accelerates through swing (flexion/extension range of motion: 15 ± 6° in stance versus 76 ± 13° in swing), whilst abduction/adduction patterns varied considerably between horses. For practitioners managing carpal injuries or assessing conformational soundness, these data establish normative three-dimensional motion patterns against which pathological restriction or excessive motion can be compared; however, the substantial individual variation in mediolateral carpal movement suggests that future studies examining larger populations will be necessary to determine how conformation and individual anatomy influence injury predisposition.
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Practical Takeaways
- •Understanding normal 3D carpal kinematics provides a baseline for recognizing abnormal joint motion that may indicate early carpal injury or dysfunction
- •Individual variation in abduction/adduction patterns suggests that conformation assessment should be considered when evaluating carpal problems, as movement patterns may differ significantly between horses
- •Knowledge of the substantial range of flexion/extension motion (76° in swing) helps explain why carpal injuries are common and supports the importance of conditioning and support strategies
Key Findings
- •All horses demonstrated carpal extension and internal rotation of the metacarpus relative to the radius during stance phase as the carpus assumed close-packed position
- •Flexion/extension showed a range of motion of 15 ± 6 degrees in stance and 76 ± 13 degrees in swing, representing the predominant rotational movement
- •Late stance initiated a flexion cycle continuing through midswing accompanied by small internal rotation cycles
- •Abduction/adduction direction varied between individual horses while other carpal motions remained generally consistent