Modelling the anisotropic electrical properties of skeletal muscle.

We present a numerical model used to analyse the anisotropic electrical properties of frog muscle, measured in vivo. The model represents the anisotropic, irregularly shaped muscle as a set of cubic elements. We develop a finite difference method to calculate the electrical resistance between two electrodes inserted longitudinally or transversely into the muscle in terms of longitudinal and transverse muscle conductivities. Comparison of the measured impedance values with the calculated resistances yields the separate variation with frequency of the two conductivity components. We also compare the results of the numerical, finite difference method with those of two simple, analytical models.