The Response of Pediatric Ribs to Quasi-static Loading: Mechanical Properties and Microstructure
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Traumatic injury is a major cause of death in the child population. Motor vehicle crashes account for a large portion of these deaths, and a considerable effort is put forth by the safety community to identify injury mechanisms and methods of injury prevention. However, construction of biofidelic anthropomorphic test devices and computational models for this purpose requires knowledge of bone properties that is difficult to obtain. The objective of this study is to characterize the relationship between mechanical properties and measures of skeletal development in the growing rib. Anterolateral segments of 44 ribs from 12 pediatric individuals (age range: 5 months to 9 years) were experimentally tested in three-point bending. Univariate mixed models were used to assess the predictive abilities of development-related variables (e.g., age, stature, histomorphometry, cross-sectional geometry) on mechanical variables (material and structural properties). Results show that stature, in addition to age, may be a reliable predictor of bone strength, and that histomorphometry has potential to explain bone properties and to further our understanding of fracture mechanisms. For example, percent secondary lamellar bone (%Sd.Ar) successfully predicts peak force (F P) and Young’s modulus (E). Application of these findings is not restricted to injury biomechanics, but can also be referenced in forensic and anthropological contexts.
KeywordsHistomorphometry Bone growth Three-point bending Injury biomechanics Thorax
With much gratitude, we would like to thank all the donors and their families who made this research possible. This research was sponsored by the National Highway Traffic Safety Administration (NHTSA), specifically the Vehicle Research and Test Center (VRTC). A Dwight D. Eisenhower Fellowship from the Federal Highway Administration (FHA) supported a graduate student on this project. The authors thank those from Nationwide Children’s Hospital: Peter Baker, Emily Chenever, Anna Hughes, and Gary Smith, and past students of the Injury Biomechanics Research Laboratory: Hannah Gustafson, Brian Suntay, Tony Vergis, and J. Jared Guth. Additionally, we would like to thank the Associate Editor, Joel Stitzel, and three anonymous reviewers for their constructive comments and assistance in improving this manuscript. The views conveyed in this manuscript reflect those of the authors and do not necessary reflect the views of their affiliated organizations or sponsors.
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