Speed of Surface Elastic Wave Propagation over the Human Chest

Abstract

Speeds of surface elastic wave propagation over the human chest along and across the ribs are found. Ten healthy male volunteers have participated in the experiment. Vibrations of a striker-vibrator and a light accelerometer in contact with the chest have been detected using a specially designed hardware and software complex. The transfer function phase for passage of elastic waves over the chest is calculated. Wave propagation speeds are found using the phase method (frequency dependence of the transfer function phase). Differences between the speeds along and across the ribs are found in the frequency ranges from 27 to 100 Hz and from 100 to 200 Hz with the maximal-to-minimal speed ratio of 1.8. It is shown that one of the causes for the differences between the speeds can be different local elasticity and viscosity of the chest tissues.