This 3D Printed 'Third Thumb' Prosthetic Can Extend Its User's Abilities

Prosthetics are often thought of as a replacement to body parts that were lost, however, this unique thumb prosthesis prototype aims to become more of an aesthetic augmentation to the body. Product designer Danielle Clode named this prototype the "Third Thumb Project", where a multi-shore 3D printing scale is employed to build the active prosthetic thumb.

Getting to grips with a third thumb

The third thumb system simply aims to replicate the dynamic motions of a real thumb. But some may find it a little strange that this foreign body part, that acts as a thumb, is controlled using the movements of the wearer's foot. Two pressure sensors are retrofitted to the under side of the toes inside the shoes. A small Bluetooth module attached to the shoe relays the foot's motions to the synthetic thumb.

[Image Source: Dani Clode Design]

There are two motors worn on the wrist, pretty much like a watch, that receive the motion signals which then pull the Bowden cable system to apply movements to the 3D printed flexible thumb. The cable system, which works like a bicycle brake, is made from Teflon tubing and wire. This clever system exploits the strong connection between the hands and feet that is evident in many real life examples like driving a vehicle, playing the piano, or using a sewing machine.

Using 3D printing technology, Clode said that it made the process of creating the third thumb more easy as it permits quick prototyping and bespoke designs for specific hand sizes and one-off production.

Making prosthesis the new body augmentation trend

Prosthetics are often viewed as a replacement for a limb or body part that has been amputated. However, Danielle Clode wanted to change the current social attitude towards the use of prosthetics and how it can augment the body. "The value of the Third Thumb is to create a catalyst for society to consider a human extension, framed in an approachable, accessible design", said Clode. "It is a tool, an experience, and a form of self-expression. When we start to extend our abilities, and when we reframe prosthetics as extensions, then we start to shift the focus from ‘fixing’ disability to extending ability".

[Image Source: Dani Clode Design]

The third thumb concept is aimed to function in two applicational scenarios. Its first potential application is to work as an aesthetic tool equipped with electronics. A multi-shore 3D printing scale is to be used where the actual thumb will be printed with soft and flexible materials, while the hand structure would be printed using a more rigid shore.

On the other hand, the third thumb could potentially be used to augment the body. It can be thought of as a "kinetic jewelry" or as a unique expression of body modification, with the same effect as getting a tattoo or piercings. Clode even expressed that the third thumb aesthetic concept could even be considered to be in the same body improvement category as plastic surgery.

"The Third Thumb aims to challenge the perception of prosthetics. By extending the body I see it creating a similar trajectory for prosthetics as glasses or plastic surgery. Creating a shift from medical device to positive body image statement".

The Third Thumb Project won the annual London Royal College of Art's Helen Hamlyn Design Awards for Creativity.

Via Danielle Clode