Human thoracic models constructed of artificial materials were subjected to blunt impact by means of an automobile steering wheel striking the replicas at various velocities. Two systems, corresponding to conditions at mid-systole and end-diastole, respectively, were tested;​ these consisted of the rib cage, the vertebral column, two lungs, muscles, the diaphragm, a vascular network permitting blood flow and an added head form with neck musculature. The experimental results indicate that the bursting of the heart due to impact is more likely to occur during diastole than systole. Vessel strains were most significant in the aorta and the superior and inferior venae cavae.