Recent firsts in cadaveric impact biomechanics research.

High-speed biplane x-ray and neutral density targets were used to examine brain displacement and deformation, as well as aortic motion and deformation within the mediastinum, during impact. Thirty-five impacts using eight human cadaver head and neck specimens and eight impacts of the intact cadaver thorax are summarized. During impact, local brain tissue tends to keep its position and shape with respect to the inertial frame, resulting in relative motion between the brain and skull and deformation of the brain. The local brain motions tend to follow looping patterns. Similar patterns are observed for impact in different planes, with some degree of posterior-anterior and right-left symmetry. Clinically relevant damage to the aorta was observed in seven of the thorax tests. The presence of atherosclerosis was demonstrated to promote tearing. The isthmus of the aorta moved dorsocranially during frontal impact and submarining loading modes. The aortic isthmus moved medially and anteriorly during impact to the left side.