 A high-frequency oscillating pressure wave with large amplitude and short duration was found in the brain after the extremity impact of a high-energy missile..." Wang et al.observed significant damage in both the hypothalamus and hippocampus regions of the brain due to remote effects of the ballistic pressure wave.In a study of a handgun injury, Sturtevant found that pressure waves from a bullet impact in the torso can reach the spine and that a focusing effect from concave surfaces can concentrate the pressure wave on the spinal cord producing significant injury.