Burnt bones and teeth: an experimental study of color, morphology, crystal structure and shrinkage

This review brings together a complex and extensive literature to address the question of whether it is possible to distinguish human from nonhuman bone using the histological appearance of cortical bone. The mammalian species included are rat, hare, badger, racoon dog, cat, dog, pig, cow, goat, sheep, deer, horse, water buffalo, bear, nonhuman primates, and human and are therefore not exhaustive, but cover those mammals that may contribute to a North American or Eurasian forensic assemblage. The review has demonstrated that differentiation of human from certain nonhuman species is possible, including small mammals exhibiting Haversian bone tissue and large mammals exhibiting plexiform bone tissue. Pig, cow, goat, sheep, horse, and water buffalo exhibit both plexiform and Haversian bone tissue and where only Haversian bone tissue exists in bone fragments, differentiation of these species from humans is not possible. Other primate Haversian bone tissue is also not distinguishable from humans. Where differentiation using Haversian bone tissue is undertaken, both the general microstructural appearance and measurements of histological structures should be applied. Haversian system diameter and Haversian canal diameter are the most optimal and diagnostic measurements to use. Haversian system density may be usefully applied to provide an upper and lower limit for humans.

Differentiating human bone from animal bone : A review of histological methods

Problems recently discovered in the Kerley method of estimating age at death from cortical microstructure are discussed. Kerley's original data have been re-analyzed to produce new regression equations and to document the original field size.

Revisions in the microscopic method of estimating age at death in human cortical bone.

The purpose of this study was to describe the age-specific distribution of midfemoral intracortical porosity throughout the cortical width in males and females. Microradiography and an automated image analysis system were used to study midfemoral cortical bone specimens from 163 white people, including 77 males and 86 females, in a recent anthropological collection covering a broad age range. In each specimen, porosity (percentage of the cortical bone area occupied by pores), pore number, and pore size were measured throughout the entire cortex and in three cortical subregions of equal width labeled the periosteal, midcortical, and endosteal subregions. For each gender, relationships linking age to porosity, pore number, and mean pore size were assessed using regression analysis. In addition, age- and site-related changes in these three variables were tested for significance using two-way analysis of variance (ANOVA). Age explained 52% of the porosity variance in females and 13.5% in males. In each gender, there were significant age- and site-related differences in porosity, pore number, and pore size. In adults aged 60 years or younger, both pore size and pore number increased with increasing age, whereas in adults older than 60 years, pore size continued to increase but pore number decreased. In males, the age-related changes in pore size and pore number were proportionally similar in the three cortical subregions. In females, in contrast, the changes predominated in the endosteal subregion and resulted in significant cortical thinning.

Distribution of Intracortical Porosity in Human Midfemoral Cortex by Age and Gender

Age- and sex-related changes in iliac cortical bone mass and remodeling

Studies were conducted to quantitate histological age changes in human bone cortex. Ground (undecalcified) and decalcified cross sections of mandible, femur and tibia were measured for: (1) number of osteons in two fields, (2) average number of lamellae per osteon, and (3) average Haversian canal diameter. These data were obtained from 59 subjects (52 males) ranging in age from 39 to 87 years. Multiple regression techniques were then utilized to estimate age at death from several combinations of these measurements. With age, the number of osteons per unit area of bone and the number of lamellae per osteon increased but Haversian canal diameter decreased. The number of lamellae per osteon had the least significant correlation with age. Multiple regression analyses indicated that in this age group age at death could be estimated to within six years of the true value in 95% of human males. Histological measurements of the mandible provided estimates that were consistently more accurate than those based on the two long bones. A monograph, prepared from mandibular measurements, can be used to estimate age at death between 40 and 80 years of age in the male human population. Significant sex differences were not noted and racial differences were not analyzed. It was concluded that, compared to existing morphologic methods, microstructure of bone cortex can be quantitated to estimate age at death more accurately. More extensive studies on race, sex and metabolic influences on age estimation from different bones would have important medico-legal and anthropologic implications. The experimental approach utilized here should also be useful in diagnostic pathology and in ageing research.

D. L. Gunberg

Papers

Estimation of Age at Death in Human Males from Quantitative Histology of Bone Fragments