Lobster Thumb

This is a prosthetic thumb designed and supplied for a recipient's request. It is intended for someone missing a complete thumb from either hand but having at least proximal and middle sections of the index finger. The thumb itself is from a Phoenix hand (120%), but in this case, it is operated by movement of the user’s index finger, assisted if necessary by the middle finger. The design could be modified for operation using other fingers.

To adjust the grip for objects of different sizes and shapes, the position of the thumb, relative to the fingers and palm, can be changed between 3 indexed positions by changing the angle between the 2 joint pivots of the thumb proximal section.

Compared to the Phoenix hand, the pivot angle of the thumb has been changed to improve the grip (based on 1st recipient preference), the length of the proximal section has been increased by 5mm, and the width of the distal section increased to retain a size 1 rubber thimblette securely.

Files and Resources:

STL Files: Link

Source CAD Files: Link

Instructions: Link