Concept of ElAp version 4

Biomechanical modelling


The ElAp must assure electrode contact during dynamic movements. Assuming that the greatest challenge is during prono-supination of the hand the following considerations have been
The forearm is a twisting element. It rotates around a skew axis given by the physical properties of the radial and the ulnar bone. We make the following approximations from anatomical drawings
At the proximal part, just below the elbow, the axis of supination has a centre of rotation. Distally at the wrist the axis is 1/3 towards the ulnar part.
The ElAp will be fixed at these two points to provide reference for the electrode and the skin movement.
ForearmAnatomy.jpg
These two parts must be linked in a way to not restrict the rotation.
It follows by the a simulation that the distance bewteen four points on both braces will change with about 10mm.
image063.jpg
PointsOfRotation.jpg