A method for scaling the muscle action is proposed and used to achieve a 3D inverse dynamic model of
the human finger with all its components scalable. This method is based on scaling the PCSA
(physiological cross-sectional area) in a Hill muscle model. Different anthropometric parameters and
maximal grip force data have been measured and their correlations have been analysed and used for
scaling the PCSA of each muscle. A linear relationship between the normalised PCSA and the product of
the length and breadth of the hand has been finally used for scaling, with a slope of 0.01315 cm-2, with the
length and breadth of the hand expressed in centimetres. The parametric muscle model has been included
in a parametric finger model previously developed by the authors, and it has been validated reproducing
the results of an experiment in which subjects from different population groups exerted maximal
voluntary forces with their index finger in a controlled postur
