Current and emerging histomorphometric and imaging techniques for assessing age-at-death and cortical bone quality

Bones are dynamic living organs that undergo continual change throughout life. An internal process of tissue renewal, called remodeling, removes mature microscopic packets of bone, and replaces them with new bone in a highly coordinated manner. To date, it remains difficult to directly observe and track individual remodeling events in cortical bone due to the small size of the structures involved. High-resolution imaging techniques hold the potential to provide novel three-dimensional information pertaining to changes in bone's microarchitecture, cortical porosity, and the remodeling process. This review critically explores the methodological approaches used historically by researchers to assess the products of remodeling within cortical bone and relate it to age-at-death estimation, extending from histology to modern ex vivo imaging modalities, and discusses the growing potential of in vivo imaging. We further provide an introduction to various histological indicators of bone quality and fragility, their forensic relevance, and examples of novel imaging modalities employed for their investigation. The review concludes with an introduction to cutting-edge in vivo four-dimensional imaging techniques that include the use of animal models to shed new light on the dynamic nature of bone, and the processes of bone aging and disease. Data gleaned from these new insights will ultimately lead to the development of future histologic age-estimation methods in forensic anthropology. This article is categorized under: Forensic Anthropology > Age Assessment Forensic Chemistry and Trace Evidence > Emerging Technologies and Methods Forensic Medicine > Imaging Modalities

Automated summary

Bones are dynamic living organs that undergo continual change throughout life. High-resolution imaging techniques have the potential to provide new information about changes in bone microarchitecture. Methodological approaches used historically by researchers to assess the products of remodeling are continuously evolving.