Search

Abstract Bone specimens were collected from the frontal and parietal bones of 4 adult, human skulls. The microstructure was characterized using microcomputed tomography (micro-CT) at about 6-μm resolution to map the change of porosity as a function of the depth, P(d), from the inner surface nearest to the brain to the outer surface nearest to the skin. A quantifiable method was developed using the measured P(d) to objectively distinguish between the three layers of the skull: the outer table, diploë , and inner table. The thickness and average porosity of each of the layers were then calculated from the measured porosity distributions, and a Gaussian function was fit to the P(d) curves. Morphological parameters were compared between the two bone types (frontal and parietal), while accounting for skull-to-skull variability. Parietal bones generally had a larger diploë accompanied by a thinner inner table. The arrangement of the porous vesicular structure within the outer table was also obtained with micro-CT scans with longer scan times, using enhanced parameters for higher resolution and lower noise in the images. From these scans, the porous structure of the bone appeared to be randomly arranged in the transverse plane, compared to the porous structure of the human femur, which is aligned in the loading direction. Graphical abstract fx1 Highlights • Quantified change of porosity from inner to outer surfaces at high-resolution. • Defined and quantitatively identified the three layers of the human skull. • Parietal has a normalized thicker diploe and thinner inner table than frontal bone. • Canal network in outer table is randomly oriented in transverse plane. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Thoracolumbar injuries resulting from motor vehicle accidents, falls, and assaults have a high risk of morbidity and mortality. However, there are no biomechanically based standards that address this problem. Methods: This study used four cadaveric porcine specimens as a model for direct spinal impact injuries to humans to determine an appropriate injury tolerance value. The anthropometric parameters of these specimens are compared with values found in a large human cadaveric dataset. Each specimen was subjected to five impacts on the dorsal surface of the lower thorax and abdomen. Results: The injuries ranged from mild spinous process fractures to endplate fractures with anterior longitudinal ligament (ALL) transactions with a maximum AIS=3. The average peak reaction force for the thoracic failure tests was 4720±1340N, and the average peak reaction force for the lumbar failure tests was 4650±1590N. Discussion: When scaled to human values using anthropometric parameters determined in this study, the force at which there is a 50% risk of injury is 10,200±3900N. This value favorably compares to that found in the existing literature on isolated vertebral segments. Summary: After demonstrating that the porcine model can be used as a spinal impact model for the human, the resulting injury risk value can be used in determining new standards for human injury risk or in guiding the design of safety equipment for the back. [Copyright &y& Elsevier]