Three-dimensional functional workspace of thumb prehension

Area of Science:

• Biomechanics
• Hand Surgery
• Kinesiology

Background:

• Assessing thumb motion is complex due to intricate anatomy and functional demands.
• Measuring hand movement during activities and post-surgical changes is clinically challenging.
• A 3D hand model offers potential for improved assessment of thumb prehension and motion.

Purpose of the Study:

• To develop and validate a kinematic model for measuring thumb and finger motion.
• To calculate the functional workspace volume for prehension tasks.
• To assess the model's utility in clinical and post-surgical evaluations.

Main Methods:

• Developed a kinematic model of the hand to track thumb and finger positions.
• Validated the model using a mechanical hand replica.
• Applied the 3D motion analysis to ten participants with a custom marker array.

Main Results:

• The kinematic model accurately measures 3D thumb joint range of motion (RoM).
• It effectively predicts functional workspace volume during functional activities.
• The thumb carpometacarpal joint is key for thumb positioning in functional tasks.

Conclusions:

• A 3D kinematic hand model provides accurate measurements of thumb RoM.
• The model predicts functional workspace, aiding in the assessment of hand function.
• This approach can enhance clinical evaluation of thumb motion and surgical interventions.