Electrical field distribution in the human body

Electrical potential differences are applied to the human body in biomedical work and sometimes by accident. The determination of electrical field patterns is important under these circumstances. The present paper gives the basis for applying electromagnetic field equations, particularly the Laplace equation, to the determination of field patterns inside the body. The approximations involved in applying the equations to the thoracic region have been analysed. Using numerical techniques and a digital computer program the field equations have been solved with appropriate boundary conditions. The results indicate that the current densities vary over the thoracic cross-section and that the size of the excitation electrodes affects the field pattern. Experiments with an electrolytic tank model confirm the analytical results.