As regards the aid with the four press studs, significant pressure force is required from the tip of the first finger. The Trapeziometacarpal joint must be kept in the most suitable position between the bone ends, by the action of the intrinsic muscles that contract to stabilise the joint.

The aim is to reduce radial dislocation of the metacarpal while applying force with the thumb, because this is a cause of pain for rhizoid arthritis pathologies.

As regards the task of doing up buttons, greater precision and independence of action by each finger is essential.
The thumb uses the pulp part to oppose the index and middle fingers, to tilt the button and push it into the button hole. Incorrect terminal
opposition makes this task impossible, due to the shape of the object.

The aid comprises 4 press studs on the one side and 4 buttons like those found on many items of clothing on the other side.