Forensic anthropology casework at the Cook County Illinois Medical Examiner's Office, Chicago, IL, 2012-2022.

Forensic anthropology has grown in recent years with increased methodological standardization, technical advancements, and increasing numbers of academic institutions offering coursework and programs at the undergraduate and graduate levels. However, few practicing forensic anthropologists publish the composition of their casework, resulting in limited understanding of the true mechanics of the field by academics and forensic professionals. This study reports on forensic anthropology casework at the Cook County Medical Examiner's Office between March 2012 and February 2022. A total of 132 cases were evaluated. Results indicate that peak months of discovery were June (n = 19) and September (n = 17), with the fewest in January (n = 5). Most discovery contexts were outdoor surface recoveries (n = 55) and were fully skeletonized (n = 47). The majority of consultation requests consisted of biological profile estimation (n = 99). An average of 77.1 days elapsed from discovery to anthropology consult, 60.3 days from consultation to anthropological analysis, and 14.1 days from analysis to report submission. Assessment of the data indicates that the impact of seasonal variation, changing Medical Examiner personnel, as well as the complexity of cases influence forensic anthropology casework in Cook County. Report and discussion of forensic anthropologists' casework strengthens our understanding of the field, allows for the formulation of best practices, and serves as data upon which decisions regarding protocol, funding, resources, and need can be based. With additional practitioners collecting and sharing their data, a clearer understanding of the scope and utility of the field will be appreciated by colleagues and the greater forensic scientific community.

Influence of climatic stress on nonmetric sexually dimorphic features of the skull and pelvis.

OBJECTIVES: Human sexual dimorphism is frequently assessed through skull and pelvic size and shape. Researchers suggest that climatic variation and the associated stress may be significant factors in sexual dimorphism's etiology. However, little research has specifically investigated climatic effects on nonmetric skeletal indicators of sex. To further appreciate the plasticity of human biology, a comparative study of standard skull and pelvic nonmetric sex indicators is presented. METHODS: A Native Alaskan archeological sample (n = 104) and a component of the Terry collection (n = 99) represent populations originating from different climatic environments in recent history. These sex-balanced groups are compared through Tukey-Kramer's method and Greene's t-test to determine any variation in degree of sexual dimorphism within and between samples. RESULTS: The results reinforce the complex and multifaceted relationship between climate and sexual dimorphism. The Terry sample demonstrated a greater degree of sexual dimorphism with statistically significant differences in robusticity of the mastoid process and nuchal crest compared with the Native Alaskans. A more "male" morphotype and reduced dimorphism are appreciated in the pelves of Native Alaskans than the Terry sample. CONCLUSIONS: This research highlights a reduction in sexual dimorphism in populations under greater climatic stress and contributes to the production of more accurate skeletal assessments in future investigations. Discussion of confounding factors suggest more research is necessary to untangle climate and human morphology's complex relationship. This study contributes to a greater appreciation of human biological plasticity, ecogeographic variation, and the evolution of modern human diversity.

Ecogeographic patterns in fetal limb proportions.

OBJECTIVES: Humans generally comply with the ecological rule of Allen (1877), with populations from tropical environments exhibiting body proportions in which limb segments are long relative to trunk height compared to temperate groups. This study tests whether ecogeographic differences in intralimb proportions are identifiable among two modern fetal samples of differing ancestry. MATERIALS AND METHODS: Data are derived from radiographic measurements of long bone diaphyseal length and crown-heel length (CHL) of contemporary, spontaneously aborted fetuses of African Americans ("black") of assumed African (tropical) ancestry and European Americans ("white") of assumed European (temperate) ancestry (n = 184). Population individual limb elements, brachial, and crural indices are compared via analyses of covariance (ANCOVA). Potential patterns of divergent allometric growth are quantified through principal components analysis (PCA). RESULTS: African ancestral distal limb elements were consistently, albeit slightly, longer than those of European ancestry, relative to CHL. None of the ANCOVA interactions with ancestry are statistically significant for limb indices. The radius was the only single element that displayed a statistically significant ancestry effect (p = 0.0435) equating to a 1 mm difference. PCA highlights that upper limbs demonstrate negative allometry and lower limbs demonstrate positive allometry with sample-specific multivariate growth patterns being nearly identical. Differences in growth allometry late in gestation make little contribution to observed differences in adult limb proportions. DISCUSSION: No statistically significant ecogeographic patterns were appreciated among intralimb proportions between these groups during the fetal period. This study contributes to a greater appreciation of phenotypic plasticity, ecogeographic variation in ontogeny, and the evolution of modern human diversity.

Variation in the human bicondylar angle.

OBJECTIVES: Investigations of the human femoral bicondylar angle have largely focused on interspecific differences and intrapopulation variation. This analysis assesses the range of variation in the bicondylar angle in humans across four populations, examining the effects of population, sex and age. MATERIALS AND METHODS: The bicondylar angle was assessed in four sex- and age-balanced adult skeletal samples-modern Terry Whites and Blacks and archaeological South Dakota Arikara and Native Alaskans. The overall range of variation was assessed, and variation specific to population, sex, and age analyzed through ANOVAs and post hoc Tukey's honestly significant difference tests. RESULTS: A one-way ANOVA highlights a significant effect of population on bicondylar angle; however, the only significant difference occurs between the Terry White and South Dakota Arikara samples. Sex displays a significant effect for the total pooled sample; yet, within population, the effect of sex is significant only among South Dakota Arikara. Age also has a significant effect on bicondylar angle in the total sample; however, the interaction between age and population is not significant. CONCLUSION: The results highlight the degree of variation in the bicondylar angle that exists intraspecifically. Differing degrees of variation due to sex suggest that sexual dimorphism is not universal in the human bicondylar angle. Furthermore, the broad impact of age on this feature is discussed, including the potential for plasticity through adulthood. By recognizing and explicitly examining morphological features that vary in human populations, we can appreciate the origins of variation and its implications for locomotor function, human diversity and evolutionary relationships. Am J Phys Anthropol 160:334-340, 2016. © 2016 Wiley Periodicals, Inc.

Developmental patterns of bilateral asymmetry in ancestral puebloans.

OBJECTIVES: Producing and maintaining a bilaterally symmetric phenotype throughout the lifespan is energetically demanding. Over the course of an individual's life, various intrinsic and external stressors impact the growth trajectory. These perturbations can compromise the allocation of energetic resources to processes that maintain developmental precision, potentially resulting in bilateral asymmetry (BA). Because different stressors are present during the lifespan, BA is a valuable tool for examining the unique factors impacting symmetrical growth and development. This study examines BA in paired long bones across a developmental skeletal series. METHODS: The humeri, radii, femora, and tibiae of 198 individuals from Ancestral Puebloan New Mexico (919-1670 CE) are analyzed to explore BA across development. Individuals are separated into five age categories, and by sex when possible, to explore patterns of BA. RESULTS: Significant BA is found in the bones of the upper limb when the interaction between bone and age is examined. Results suggest that BA in the humerus and radius becomes more right-biased with age. These directional trends are not observed in the lower limbs. Division into age categories illuminates patterns of asymmetry associated with age-related activities and physiological maturity, indicating that BA is differentially affected by varying environmental stressors across development. CONCLUSIONS: Our findings support the hypothesis that BA in long bones is influenced by environmental stressors that impact an individual's ability to produce symmetric morphological traits over the lifespan. Right-biased BA in the upper limb bones indicates that this variation from a symmetric ideal is strongly influenced by handedness resulting from habitual manual activities. Am. J. Hum. Biol. 28:421-430, 2016. © 2015 Wiley Periodicals, Inc.

Intercondylar eminences and their effect on the maximum length measure of the tibia.

Maximum length measurement of the tibia has been found to be variable both in description and implementation. Historically, the literature often excludes the intercondylar eminences from the tibia in metric analysis. This paper explores the quantitative effects of inclusion or exclusion of the eminences on the maximum length measure across ancestral population, age and sex in five human adult populations of American Whites and Blacks, two Native American samples, and East Asians. A Tukey's post hoc comparison was employed to determine the overall effect of inclusion the intercondylar eminences has on metric assessment of the tibia. Results show no significant effect on comparative analysis of the tibia by age or sex. However, the difference between sample means by ancestry is significant (p < 0.0001). These results pose interesting questions concerning the morphological differences between ancestral groups. This investigation prompts further study of population variation of the human knee.