Three-dimensional carpal kinematics of trotting horses.

This research paper investigates the three-dimensional (3D) movements of the carpal joint (equivalent to the human wrist) in horses during trotting, aiming to better understand joint function and relevant injuries. The study finds notable consistency and also individual differences in these movements.

Objective and Methods

The goal of this study was to measure and understand the three-dimensional movements and kinematics of the horse’s carpal joint during trotting. The researchers:

• Used bone-fixed markers on the radius and third metacarpus of the right forelimb on three healthy horses.
• Recorded three-dimensional trajectories of these markers at a high speed (120 Hz), using a six-camera analysis system.
• Calculated the joint movements as helical angles between the two bone segments, utilizing a spatial attitude method.

Results

The results showed consistent movement patterns across the horses despite individual variations, particularly concerning abduction/adduction (lateral movement of limb). Detailed findings were as follows:

• During trotting, all the horses demonstrated carpal extension and internal rotation of the metacarpus relative to the radius as the carpus moved into a close-packed position.
• In the later stage of stance (when the horse’s foot is on the ground), the carpus started to flex, continuing this action through the mid-swing phase. This was accompanied by slight internal rotation.
• A range of motion for flexion/extension was calculated to be 15 +/- 6 degrees during stance and 76 +/- 13 degrees during swing.
• The direction of lateral movement, that is abduction (outward movement) or adduction (inward movement), varied among horses.

Conclusions

Understanding these carpal movements could provide useful insights into the cause and pathology of carpal injuries in horses. However, the study also highlighted probable disparities between individuals. This leads to the study’s recommendation that further research be conducted on a larger group of horses to investigate the impact of an individual horse’s conformation (its physical characteristics and structure) on its carpal motion.