The mechanical properties of the adult human skull are well documented, but little information is available for the infant skull. To determine the age-dependent changes in skull properties, we tested human and porcine infant cranial bone in three-point bending. The measurement of elastic modulus in the human and porcine infant cranial bone agrees with and extends previous published data [McPherson, G. K., and Kriewall, T. J. (1980), J. Biomech., 13, pp. 9-16] for human infant cranial bone. After confirming that the porcine and human cranial bone properties were comparable, additional tensile and three-point bending studies were conducted on porcine cranial bone and suture. Comparisons of the porcine infant data with previously published adult human data demonstrate that the elastic modulus, ultimate stress, and energy absorbed to failure increase, and the ultimate strain decreases with age for cranial bone. Likewise, we conclude that the elastic modulus, ultimate stress, and energy absorbed to failure increase with age for sutures. We constructed two finite element models of an idealized one-month old infant head, one with pediatric and the other adult skull properties, and subjected them to impact loading to investigate the contribution of the cranial bone properties on the intracranial tissue deformation pattern. The computational simulations demonstrate that the comparatively compliant skull and membranous suture properties of the infant brain case are associated with large cranial shape changes, and a more diffuse pattern of brain distortion than when the skull takes on adult properties. These studies are a fundamental initial step in predicting the unique mechanical response of the pediatric skull to traumatic loads associated with head injury and, thus, for defining head injury thresholds for children.

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Only sparse experimental pediatric tissue tolerance data are available for the development of pediatric surrogates and associated injury reference values. The objective of this study is to improve the efficacy of the CRABI series anthropometric test devices by increasing the foundational data used for head injury and skull fracture. To accomplish this, this study evaluated and refined the CRABI-6 injury assessment reference values (IARV) associated with skull fracture by correlating the test device response with the detailed fracture results of 50 infant cadaver drop studies reported by Weber in 1984 and 1985. Using the CRABI-6 test device, four 82-cm height free fall impacts were performed onto each of four different impact surfaces: concrete, carpet, 2-cm foam mat, and an 8-cm thick camel hair blanket. Average and standard deviation of peak head linear acceleration and HIC 36 (Head Injury Criteria) were computed for each impact surface. The average CRABI impact response was mapped to the Weber fracture outcomes for corresponding impact surfaces and logistic regression was performed to define a skull fracture risk curve based on exposure. The 5%, 25%, 50%, 75%, and 95% risk for skull fracture correlated with a CRABI-6 peak linear head acceleration of 50, 70, 82, 94, and 114 g's and a HIC 36 of 87, 214, 290, 366 and 493, respectively. This study made use of the most extensive set of controlled infant cadaver head impact and fracture data currently available. Previous head IARVs for the CRABI-6 are given by Melvin (1995) and by Klinich et al. (2002). Based on a review of pediatric tissue experiments, scaling of adult and child dummy IARVs, and sled tests, Melvin suggested a HIC 22 of 390 and a limit on peak head acceleration of 50 g's. Klinich et al. reported the results of three reconstructions of airbag-related infant head injuries and three additional reconstructions not associated with head injury. They estimated the 50% risk of minor skull fracture to be 85 g's and 220 HIC 15 . These previously reported estimates appear to be in agreement with the results reported from this study for CRABI-6 IARV of 50% risk of skull fracture at 82 g's and 290 HIC 36 .

The medical usefulness of smartphones continues to evolve as third-party applications exploit and expand on the smartphones' interface and capabilities. This technical report describes smartphone still-image capture techniques and video-sequence recording capabilities during postmortem monocular indirect ophthalmoscopy. Using these devices and techniques, practitioners can create photographic documentation of fundal findings, clinically and at autopsy, without the expense of a retinal camera. Smartphone image acquisition of fundal abnormalities can promote ophthalmological telemedicine--especially in regions or countries with limited resources--and facilitate prompt, accurate, and unbiased documentation of retinal hemorrhages in infants and young children.

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