Development of a paediatric prosthetic hand with a two-degree-of-freedom thumb

A new paediatric prosthetic hand with multiple grasping patterns was presented in this thesis. The purpose of this new design was to improve performance of conventional child prostheses by providing a more functional hand. Some special mechanisms were designed, which allowed the thumb of the new hand to be set in different positions. These positions correspond to common grasping patterns of the natural hand palmar, lateral, and cylindrical/spherical. A three dimensional computer simulation model was built to obtain proper initial positions of the thumb and fingers. A working prototype was fabricated. Initial tests focused on the mechanical properties of the hand. Test result indicated that this new hand met design requirements.;A preliminary functional evaluation was carried out with a child alternatively wearing a conventional prosthetic hand and the experimental hand. The purposes of this investigation were to examine the performance of the new hand and to determine additional functional benefits derived from using the hand. Results from the clinical evaluation indicated that the new hand performed as well as a conventional hand. It had added functional benefits in that compensatory body movements were minimized, and a larger variety of objects could be held with increased stability.;Contributions of this work include development of the first childsized prosthetic hand in which the thumb can be placed in different positions. A novel mechanism was designed and built to ensure locking of thumb rotation during the performance of grasping activities.