Spatial dependence of the phase in localized bioelectrical impedance analysis.

The variety of phase functions, theta(z) = arctan X(z)/R(z), observed earlier on the thighs of healthy and seriously ill subjects via localized bioelectrical impedance analysis, can be represented by a model which combines realistic thigh shapes with homogeneous, axially symmetric conductivity tensors. While quantitative results depend sensitively on the way current is injected, it appears to be generally true that d theta/d(z) < 0 whenever phi(r) > phi(z) (and vice versa), where phi(r) and phi(z) are the phases of the radial and longitudinal conductivity components.