Biological Anthropology of the Human Skeleton, 2019
The use of quantitative bone histology (histomorphometry) to estimate age at death is well establ... more The use of quantitative bone histology (histomorphometry) to estimate age at death is well established. As with any method of analysis, practitioners must be familiar with its biological basis, sources of error, and limitations. This chapter discusses the physiological basis for histomorphometric methods. It also addresses important issues, such as sex and population variation, and the effects of physical activity and pathology, which should be considered when using cortical bone histomorphometry (quantitative histology) to estimate age at death. Appendix A provides worked examples of two techniques commonly used for age estimation, including labeled schematic diagrams. Appendix B profiles selected age estimation techniques applicable to various skeletal sampling sites.
Sociopolitics of Migrant Death and Repatriation, 2018
This chapter traces the movement of deceased migrants in South Texas through the system of identi... more This chapter traces the movement of deceased migrants in South Texas through the system of identification and repatriation. Given significant differences in funding, resources, labor power, institutional support, and time, the timing and movement of bodies through the process are highly variable. In many ways, the fragmentation and differential support for volunteer forensic scientists have produced particular systems-level nodes where bodies may wait “in limbo” for years. This chapter considers constraints faced by forensic scientists and the systemic implications of those individual constraints.
Skeletal analysis is integral to research in biological anthropology, especially in fields such a... more Skeletal analysis is integral to research in biological anthropology, especially in fields such as forensic anthropology, bioarchaeology, zooarchaeology, paleontology, and paleopathology. The focus on skeletal remains in these fields relies on unique attributes of bone. Bone is a dynamic tissue in which important metabolic processes, including growth and development, and biomechanical adaptations (i.e., kinds and levels of physical activity) occur, and these metabolic processes are recorded in bone microstructure. Histological analysis provides a way to access this record. In addition, because of the mineralized composition of bone tissue, this record can persist and is observable long after death and the decomposition of other tissues. This article serves to provide readers with basic readings that are essential for students and researchers who seek to undertake histological analysis of skeletal remains in an anthropological context. The content includes references relating to basic skeletal biology necessary to understand and interpret histological methods; valuable reviews and critiques of histological methodology and methods; examples of methods proven to be applicable in forensic anthropology, bioarchaeology, paleontology, paleopathology, and related fields; and references of historical importance.
Anatomical crania are occasionally encountered in forensic anthropology laboratories when that ma... more Anatomical crania are occasionally encountered in forensic anthropology laboratories when that material is mistaken for forensically significant human remains. Using craniometric analyses and statistical measures of sample homogeneity, we determine whether anatomical material can be described as a single, homogenous group or as a diverse mix of populations. Twenty-one interlandmark distances were collected from 85 anatomical preparations. Distance measures were calculated between all pairs using a pooled within-sample variance/covari-ance matrix and then subjected to a Defrise-Gussenhoven test between each paired distance to test whether each pair was drawn randomly from the same population. In the Defrise-Gussenhoven analysis, twenty-two percent (n = 66) of the 300 pairwise combinations were significant at the 0.05 level or below. The level of homogeneity suggests a majority of that material originated from the subcontinent of India or West Asia. Therefore, anatomical material can be viewed as a moderately homogenous group, but with a shared taphonomic history.
Intracortical remodeling, and the osteons it produces, is one aspect of bone’s microstructure tha... more Intracortical remodeling, and the osteons it produces, is one aspect of bone’s microstructure that is influenced by and, in turn, can influence its mechanical properties. Previous research examining the spatial distribution of intracortical remodeling density across the femoral midshaft has been limited to either considering only small regions of the cortex, or when looking at the entirety of the cortex considering only a single individual. This study examined the spatial distribution of all remodeling events (intact osteons, fragmentary osteons, and resorptive bays) across the entirety of the femoral midshaft in a sample of 30 modern cadaveric donors. The sample consisted of 15 males and 15 females, aged 21–97 years at time of death. Using geographic information systems software, the femoral cortex was subdivided radially into thirds and circumferentially into octants, and the spatial location of all remodeling events was marked. Density maps and calculation of osteon population density in cortical regions of interest revealed that remodeling density is typically highest in the periosteal third of the bone, particularly in the lateral and anterolateral regions of the cortex. Due to modeling drift, this area of the midshaft femur has some of the youngest primary tissue, which consequently reveals that the lateral and anterolateral regions of the femoral midshaft have higher remodeling rates than elsewhere in the cortex. This is likely the result of tension/shear forces and/or greater strain magnitudes acting upon the anterolateral femur, which results in a greater amount of microdamage in need of repair than is seen in the medial and posterior regions of the femoral midshaft, which are more subject to compressive forces and/or lesser strain magnitudes.
Most macroscopic skeletal aging techniques used by forensic anthropologists have been developed a... more Most macroscopic skeletal aging techniques used by forensic anthropologists have been developed and tested only on reference material from western populations. This study examined the performance of six aging techniques on a known age sample of 88 Southeast Asian individuals. Methods examined included the Suchey-Brooks method of aging the symphyseal face of the os pubis (Brooks and Suchey 1990), Buckberry and Chamberlain’s (2002) and Osborne et al.’s (2004) revisions of the Lovejoy et al. (1985) method of aging the auricular surface of the ilium, İşcan et al.’s (1984, 1985) method of aging the sternal end of the fourth rib, and Meindl and Lovejoy’s (1985) methods for aging both lateral-anterior and vault sutures on the cranium. The results of this study indicate that application of aging techniques commonly used in forensic anthropology to individuals identified as Asian, and more specifically Southeast Asian, should not be undertaken injudiciously. Of the six individual methods tested here, the Suchey-Brooks pubic symphysis aging method performs best, though average age estimates were still off by nearly 10 years or greater. Methods for aging the auricular surface perform next best, though the Osborne et al. method works better for individuals below 50 years and the Buckberry and Chamberlain method works better for those above 50 years. Methods for age estimation from the sternal ends of the fourth rib and vault and lateral-anterior cranial sutures perform poorly and are not recommended for use on remains of Southeast Asian ancestry. Combining age estimates from multiple indicators, specifically the pubic symphysis and one auricular surface method, was superior to individual methods. Data and a worked example are provided for calculating the conditional probability that an individual belongs to a particular age decade, though overall age estimates may still be broad.
Estimating stature in human skeletal remains of Asian ancestry is problematic for forensic anthro... more Estimating stature in human skeletal remains of Asian ancestry is problematic for forensic anthropologists due to the paucity and uncertain suitability of regression formulae. To address this issue, our study analyzed 64 individuals from a modern skeletal collection of South-East Asian origin and developed population-specific ordinary least squares regression formulae to estimate skeletal height from each of the long bones of the upper and lower limbs, as well as from trunk length. Results indicate that the most accurate estimates of skeletal height from a single bone (as measured by standard error of the estimate—SEE) are from tibial length in males (SEE = 2.40 cm) and from humeral length in females (SEE = 2.59 cm), followed by femoral length (SEE = 2.84 cm). When multiple elements are considered, the combination of femoral and tibial length yields the best estimates in both sexes as well as combined sex samples (male SEE = 2.40 cm; female SEE = 2.77 cm; combined sex SEE = 2.54 cm).
Assessment of tooth cementum annulations (TCA) is acknowledged for its potential as a more accura... more Assessment of tooth cementum annulations (TCA) is acknowledged for its potential as a more accurate method for estimating age-at-death than conventional macroscopic methods typically employed. Thermal alteration of remains in a forensic context is not uncommon; however, the use of TCA in heat-treated remains has hitherto received no quantitative assessment of accuracy. This study applies TCA to a sample of modern teeth of known demographics after experimental heat treatment at 600, 800 and 1000°C. Cementum annulations do survive thermal alteration; however, their visibility is dependent on exposure temperature. Physical and chemical changes resulted in TCA being applicable to only 63.3% of samples. An overall correlation to known age of r = 0.522 (p < 0.05) was found, while correlations of r = 0.868 (p < 0.01), r = 0.249, and r = 0.185, were found for 600, 800, and 1000°C subsets, respectively. These results indicate that in teeth exposed to temperatures >600°C, TCA no longer yields accurate enough results to be of use in forensic investigations.
American Journal of Physical Anthropology, Aug 2012
Geographic information systems (GIS) software is typically used for analyzing geographically dist... more Geographic information systems (GIS) software is typically used for analyzing geographically distributed data, allowing users to annotate points or areas on a map and attach data for spatial analyses. While traditional GIS-based research involves geo-referenced data (points tied to geographic locations), the use of this technology has other constructive applications for physical anthropologists. The use of GIS software for the study of bone histology offers a novel opportunity to analyze the distribution of bone nano- and microstructures, relative to macrostructure and in comparison to other variables of interest, such as biomechanical loading history. This approach allows for the examination of characteristics of single histological features while considering their role at the macroscopic level. Such research has immediate promise in examining the load history of bone by surveying the functional relationship between collagen fiber orientation and strain mode. The diversity of GIS applications that may be utilized in bone histology research is just beginning to be explored. The goal of this study is to offer a reliable methodology for such investigation and our objective is to quantify the heterogeneity of bone microstructure over an entire cross-section of bone using ArcGIS v 9.3 (ESRI). This was accomplished by identifying the distribution of remodeling units in a human metatarsal relative to bending axes. One biomechanical hypothesis suggests that collagen fiber orientation, manifested by patterns of birefringence, are indicative of mode of strain during formation. This study demonstrates that GIS can be used to investigate, describe, and compare such patterns through histological mapping.
Osteon population density (OPD) in cortical bone is known to be useful in estimating age at death... more Osteon population density (OPD) in cortical bone is known to be useful in estimating age at death. Cortical thickness has also been investigated though it has been met with varied results, and prior research has measured this manually, sometimes arbitrarily. Previous research from our lab demonstrated that when the femoral cortex was divided circumferentially into anterior, posterior, medial, and lateral quadrants, and radially into periosteal, middle, and endosteal thirds, a combination of the periosteal and middle thirds from the anterior and lateral quadrants produced the most accurate prediction model for estimating age at death (adjusted R2=0.907, p<0.000). This current research sought to examine cortical thickness, measured objectively, in the quadrants of the femur to see if their inclusion would increase the accuracy of estimating age at death.
Thirty complete cross-sections from modern cadaveric femora were used, 15 of each sex, ranging from 21–97 years. A custom MATLAB code was written to evaluate cortical thickness by measuring a series of lines between + 10% of the quadrant center, from the periosteal to endosteal border, each perpendicular to a tangent line based on a periosteal node.
Measurements of cortical thickness from the anterior and lateral quadrants did not significantly correlate with age at death, though normalized by total subperiosteal area, anterior cortical thickness did significantly correlate with age. Combining anterior cortical thickness with OPD from the regions mentioned above, neither increased nor decreased the predictive ability of the regression function (adjusted R2=0.907, p<0.000) to estimate age at death.
After attending this presentation, attendees will understand the current issues with histological... more After attending this presentation, attendees will understand the current issues with histological age estimation, and the effect that region of interest (ROI) size has on the relationship between osteon population density (OPD) and age-at-death estimation. This presentation will impact the forensic science community by demonstrating that the amount of bone sampled/analyzed in histological age assessment can have a profound impact on the ability to accurately estimate age-at-death. This will inform future histological research, resulting in higher quality forensic research and practice. As a complement to macroscopic aging methods, or when necessary macroscopic elements are damaged/absent, age can be estimated through histological examination of remodeling events in cortical bone. To date, the femoral midshaft has been the most commonly employed site for histological studies; however, a consensus is lacking on how much bone to analyze when quantifying remodeling, as existing methods employ ROIs that differ in size, number, and location. Recently, histological research at the femoral midshaft has proliferated due to the revival of the Ericksen femur collection as an active resource. The current study is a meta-analysis of three recent studies that provide a unique opportunity to assess the effect of ROI size on the relationship between OPD and age. All three studies analyzed here (Ingvoldstad1, Crowder/Dominguez2, and Gocha3 methods) primarily utilized the Ericksen collection, examined the anterior region of the femur, and quantified remodeling according to the same standard histological definitions. The Ingvoldstad method examined 200 individuals (97 males, 103 females), aged 30–97 years (average=71 years), all from the Ericksen collection; a fixed ROI size of 3.00 mm2 was used to quantify remodeling at eight anatomical and biomechanical locations around the femoral cortex, though only anterior data are analyzed here. The Crowder/Dominguez method examined 320 individuals (170 males, 150 females), aged 15–97 (average=66 years), 87% of which were from the Ericksen collection. This method used a topographic sampling strategy, separating a 5 mm wide section of the anterior femur into 10 columns and reading every other frame using a Merz reticule; this resulted in an average ROI size of 18.30 mm2, with an average of 9.52 mm2 of bone analyzed. The Gocha method examined only 30 individuals (15 male, 15 female), aged 21–97 years (average=59 years), 83% of which were from the Ericksen collection. This method examined remodeling over the entirety of the femoral midshaft, though only anterior octant and quadrant data are analyzed here; average octant ROI size was 41.82 mm2, average quadrant ROI size was 89.93 mm2. Statistical analyses were performed in SPSS 23. Kolmogorov-Smirnov tests demonstrated OPD values for all methods to be normally distributed (all p-values >0.070). The relationship between OPD and age was assessed through Pearson’s correlation coefficients, as well as the adjusted R2 value of linear regression predictive models; all of these statistical measures were statistically significant (all p-values <0.043). One author (VMD), who collected the majority of the data for the Crowder/Dominguez method, also performed interobserver error measures for the Ingvoldstad and Gocha studies, neither of which demonstrated significant differences between observers. The correlation coefficient for the Ingvoldstad method was R=0.143, and the adjusted R2=0.016, indicating OPD explained only 1.6% of the variation in age-at-death. The correlation coefficient for the Crowder/Dominguez method was R=0.681, and the adjusted R2=0.462, indicating OPD explained 46.2% of the variation in age-at-death. The correlation coefficient for the Gocha Octant method was R=0.907, and the adjusted R2=0.817, indicating OPD explained 81.7% of the variation in in age at death. For the Gocha Quadrant method, the correlation coefficient was R=0.918 and the adjusted R2=0.838, indicating OPD explained 83.8% of the variation in age at death. Results indicate that ROI size has a significant effect on the ability to predict age-at-death from histological remodeling. Examination of small, isolated ROIs is not recommended, as such an approach is more susceptible to random variation in variable distribution and can negatively affect interpretation. Instead, future studies should examine larger ROIs to maximize histological remodeling’s ability to predict age-at-death.
After attending this presentation, attendees will better understand the role of the anthropologis... more After attending this presentation, attendees will better understand the role of the anthropologist in the identification and repatriation processes of deceased migrants found along the US-Mexico border. This presentation will impact the forensic science community by highlighting how the role of an anthropologist varies in identification and repatriation processes depending on local and state laws and may extend well beyond skeletal analysis. Often law enforcement may be responsible for identification efforts while an anthropologist provides a report to a medical examiner, law enforcement agency, coroner, or Justice of the Peace (JP). In other circumstances, however, responsibility for identification may fall to the anthropologist. Depending on jurisdiction, these responsibilities vary with the anthropologist taking on new roles. These varied roles will be examined through a survey of three partner organizations of the Forensic Border Coalition (FBC): the Argentine Forensic Anthropology Team (EAAF), the Pima County Office of the Medical Examiner (PCOME), and the Forensic Anthropology Center at Texas State (FACTS). A generalized description of identification and repatriation processes is given for migrant deaths in Arizona, while case studies will be discussed to illustrate the complexities of these processes in Texas. The EAAF investigates migrant deaths along both sides of the US-Mexico border. Regarding cases of unidentified remains recovered in the US, EAAF facilitates the collection of family reference sample DNA for comparison to DNA samples from remains likely to correspond to migrants. When DNA analysis suggests an identification, the EAAF works with Forensic Data Banks on Missing Migrants or other mechanisms within the migrant’s country of origin to compare all antemortem and postmortem records to confirm an identification. The EAAF writes an identification report and works with the appropriate local US officials to legally recognize the identification. In recent years EAAF has helped identify 65 migrants who perished within the US. Repatriation is then handled by a Consulate’s office, overseen by the Foreign Affairs Ministry from the decedent's home county. In Arizona, forensic anthropological investigations of presumed migrants takes place at the PCOME. Between 2001 and 2013, the PCOME received the remains of 2,203 presumed migrants, and successfully identified 1,463. For cases requiring skeletal analysis, anthropologists at the PCOME construct both a biological and cultural profile. Once an identification hypothesis is made, the anthropologist compares all antemortem and postmortem data, writes an identification report, and briefs the Medical Examiner who legally signs off on an identification. If the decedent is to be returned to their country of origin, the local Consulate’s office manages the repatriation of the remains, a process that can take weeks to months. Since 2013, Operation Identification (OpID), housed within FACTS, has received the remains of 87 presumed migrants, many through exhumation efforts carried out by Baylor University and University of Indianapolis. DNA analysis, along with anthropological analyses of the skeletal remains and personal effects, are the primary sources for identification hypotheses. Once a DNA association is reported, anthropologists associated with OpID compare all antemortem and postmortem data, write an identification report, and brief the appropriate JP who legally approves the identification. Since 2014, OpID has helped facilitate nine identifications, however only five of those individuals have been successfully repatriated. The repatriation process for counties without a medical examiner requires the coordinated efforts of Consulate offices, the funeral home handling the repatriation, the funeral home that originally filed the death certificate, and the JP, which can all vary by case. Unlike the Arizona model where these efforts are centralized, in Texas these parties can be vastly separated by geography, culture, and available resources, which can result in a breakdown of communication and stagnation of the repatriation process. In the most egregious example, an individual identified by OpID in August 2014 has still not been repatriated as of July 2016. This unfortunate reality has led to anthropologists in Texas adopting new roles as de facto case managers and stewards of identification and repatriation processes. Anthropologists associated with OpID, with help from other FBC partners, are now facilitating/mediating communication between funeral homes, law enforcement, JPs, Medical Examiners, and the decedent’s family members. It is believed these expanded roles of the anthropologist will help streamline and hasten the repatriation of remains.
Brooks County in South Texas is part of a known migrant corridor used by undocumented border cros... more Brooks County in South Texas is part of a known migrant corridor used by undocumented border crossers entering Texas through the U.S./Mexico border. Operation Identification (OpID) at Texas State University is a project which aims to facilitate the identification and repatriation of human remains found along or near the South Texas border through scientific analysis and collaboration with governmental and nongovernmental organization. The project utilizes a multifaceted anthropological approach towards identification including traditional osteological, dental, isotopic, genetic, and histological analyses. Additionally, OpID incorporates biocultural lines of evidence not commonly used in biological anthropology such as analyses of missing persons reports for comparison of antemortem and postmortem data, and exmination of personal effects to help establish identification hypotheses. Since 2013, OpID has received a total of 195 sets of human remains or presumed migrants and has helped facilitate in the identification of 18 individuals.
Biological Anthropology of the Human Skeleton, 2019
The use of quantitative bone histology (histomorphometry) to estimate age at death is well establ... more The use of quantitative bone histology (histomorphometry) to estimate age at death is well established. As with any method of analysis, practitioners must be familiar with its biological basis, sources of error, and limitations. This chapter discusses the physiological basis for histomorphometric methods. It also addresses important issues, such as sex and population variation, and the effects of physical activity and pathology, which should be considered when using cortical bone histomorphometry (quantitative histology) to estimate age at death. Appendix A provides worked examples of two techniques commonly used for age estimation, including labeled schematic diagrams. Appendix B profiles selected age estimation techniques applicable to various skeletal sampling sites.
Sociopolitics of Migrant Death and Repatriation, 2018
This chapter traces the movement of deceased migrants in South Texas through the system of identi... more This chapter traces the movement of deceased migrants in South Texas through the system of identification and repatriation. Given significant differences in funding, resources, labor power, institutional support, and time, the timing and movement of bodies through the process are highly variable. In many ways, the fragmentation and differential support for volunteer forensic scientists have produced particular systems-level nodes where bodies may wait “in limbo” for years. This chapter considers constraints faced by forensic scientists and the systemic implications of those individual constraints.
Skeletal analysis is integral to research in biological anthropology, especially in fields such a... more Skeletal analysis is integral to research in biological anthropology, especially in fields such as forensic anthropology, bioarchaeology, zooarchaeology, paleontology, and paleopathology. The focus on skeletal remains in these fields relies on unique attributes of bone. Bone is a dynamic tissue in which important metabolic processes, including growth and development, and biomechanical adaptations (i.e., kinds and levels of physical activity) occur, and these metabolic processes are recorded in bone microstructure. Histological analysis provides a way to access this record. In addition, because of the mineralized composition of bone tissue, this record can persist and is observable long after death and the decomposition of other tissues. This article serves to provide readers with basic readings that are essential for students and researchers who seek to undertake histological analysis of skeletal remains in an anthropological context. The content includes references relating to basic skeletal biology necessary to understand and interpret histological methods; valuable reviews and critiques of histological methodology and methods; examples of methods proven to be applicable in forensic anthropology, bioarchaeology, paleontology, paleopathology, and related fields; and references of historical importance.
Anatomical crania are occasionally encountered in forensic anthropology laboratories when that ma... more Anatomical crania are occasionally encountered in forensic anthropology laboratories when that material is mistaken for forensically significant human remains. Using craniometric analyses and statistical measures of sample homogeneity, we determine whether anatomical material can be described as a single, homogenous group or as a diverse mix of populations. Twenty-one interlandmark distances were collected from 85 anatomical preparations. Distance measures were calculated between all pairs using a pooled within-sample variance/covari-ance matrix and then subjected to a Defrise-Gussenhoven test between each paired distance to test whether each pair was drawn randomly from the same population. In the Defrise-Gussenhoven analysis, twenty-two percent (n = 66) of the 300 pairwise combinations were significant at the 0.05 level or below. The level of homogeneity suggests a majority of that material originated from the subcontinent of India or West Asia. Therefore, anatomical material can be viewed as a moderately homogenous group, but with a shared taphonomic history.
Intracortical remodeling, and the osteons it produces, is one aspect of bone’s microstructure tha... more Intracortical remodeling, and the osteons it produces, is one aspect of bone’s microstructure that is influenced by and, in turn, can influence its mechanical properties. Previous research examining the spatial distribution of intracortical remodeling density across the femoral midshaft has been limited to either considering only small regions of the cortex, or when looking at the entirety of the cortex considering only a single individual. This study examined the spatial distribution of all remodeling events (intact osteons, fragmentary osteons, and resorptive bays) across the entirety of the femoral midshaft in a sample of 30 modern cadaveric donors. The sample consisted of 15 males and 15 females, aged 21–97 years at time of death. Using geographic information systems software, the femoral cortex was subdivided radially into thirds and circumferentially into octants, and the spatial location of all remodeling events was marked. Density maps and calculation of osteon population density in cortical regions of interest revealed that remodeling density is typically highest in the periosteal third of the bone, particularly in the lateral and anterolateral regions of the cortex. Due to modeling drift, this area of the midshaft femur has some of the youngest primary tissue, which consequently reveals that the lateral and anterolateral regions of the femoral midshaft have higher remodeling rates than elsewhere in the cortex. This is likely the result of tension/shear forces and/or greater strain magnitudes acting upon the anterolateral femur, which results in a greater amount of microdamage in need of repair than is seen in the medial and posterior regions of the femoral midshaft, which are more subject to compressive forces and/or lesser strain magnitudes.
Most macroscopic skeletal aging techniques used by forensic anthropologists have been developed a... more Most macroscopic skeletal aging techniques used by forensic anthropologists have been developed and tested only on reference material from western populations. This study examined the performance of six aging techniques on a known age sample of 88 Southeast Asian individuals. Methods examined included the Suchey-Brooks method of aging the symphyseal face of the os pubis (Brooks and Suchey 1990), Buckberry and Chamberlain’s (2002) and Osborne et al.’s (2004) revisions of the Lovejoy et al. (1985) method of aging the auricular surface of the ilium, İşcan et al.’s (1984, 1985) method of aging the sternal end of the fourth rib, and Meindl and Lovejoy’s (1985) methods for aging both lateral-anterior and vault sutures on the cranium. The results of this study indicate that application of aging techniques commonly used in forensic anthropology to individuals identified as Asian, and more specifically Southeast Asian, should not be undertaken injudiciously. Of the six individual methods tested here, the Suchey-Brooks pubic symphysis aging method performs best, though average age estimates were still off by nearly 10 years or greater. Methods for aging the auricular surface perform next best, though the Osborne et al. method works better for individuals below 50 years and the Buckberry and Chamberlain method works better for those above 50 years. Methods for age estimation from the sternal ends of the fourth rib and vault and lateral-anterior cranial sutures perform poorly and are not recommended for use on remains of Southeast Asian ancestry. Combining age estimates from multiple indicators, specifically the pubic symphysis and one auricular surface method, was superior to individual methods. Data and a worked example are provided for calculating the conditional probability that an individual belongs to a particular age decade, though overall age estimates may still be broad.
Estimating stature in human skeletal remains of Asian ancestry is problematic for forensic anthro... more Estimating stature in human skeletal remains of Asian ancestry is problematic for forensic anthropologists due to the paucity and uncertain suitability of regression formulae. To address this issue, our study analyzed 64 individuals from a modern skeletal collection of South-East Asian origin and developed population-specific ordinary least squares regression formulae to estimate skeletal height from each of the long bones of the upper and lower limbs, as well as from trunk length. Results indicate that the most accurate estimates of skeletal height from a single bone (as measured by standard error of the estimate—SEE) are from tibial length in males (SEE = 2.40 cm) and from humeral length in females (SEE = 2.59 cm), followed by femoral length (SEE = 2.84 cm). When multiple elements are considered, the combination of femoral and tibial length yields the best estimates in both sexes as well as combined sex samples (male SEE = 2.40 cm; female SEE = 2.77 cm; combined sex SEE = 2.54 cm).
Assessment of tooth cementum annulations (TCA) is acknowledged for its potential as a more accura... more Assessment of tooth cementum annulations (TCA) is acknowledged for its potential as a more accurate method for estimating age-at-death than conventional macroscopic methods typically employed. Thermal alteration of remains in a forensic context is not uncommon; however, the use of TCA in heat-treated remains has hitherto received no quantitative assessment of accuracy. This study applies TCA to a sample of modern teeth of known demographics after experimental heat treatment at 600, 800 and 1000°C. Cementum annulations do survive thermal alteration; however, their visibility is dependent on exposure temperature. Physical and chemical changes resulted in TCA being applicable to only 63.3% of samples. An overall correlation to known age of r = 0.522 (p < 0.05) was found, while correlations of r = 0.868 (p < 0.01), r = 0.249, and r = 0.185, were found for 600, 800, and 1000°C subsets, respectively. These results indicate that in teeth exposed to temperatures >600°C, TCA no longer yields accurate enough results to be of use in forensic investigations.
American Journal of Physical Anthropology, Aug 2012
Geographic information systems (GIS) software is typically used for analyzing geographically dist... more Geographic information systems (GIS) software is typically used for analyzing geographically distributed data, allowing users to annotate points or areas on a map and attach data for spatial analyses. While traditional GIS-based research involves geo-referenced data (points tied to geographic locations), the use of this technology has other constructive applications for physical anthropologists. The use of GIS software for the study of bone histology offers a novel opportunity to analyze the distribution of bone nano- and microstructures, relative to macrostructure and in comparison to other variables of interest, such as biomechanical loading history. This approach allows for the examination of characteristics of single histological features while considering their role at the macroscopic level. Such research has immediate promise in examining the load history of bone by surveying the functional relationship between collagen fiber orientation and strain mode. The diversity of GIS applications that may be utilized in bone histology research is just beginning to be explored. The goal of this study is to offer a reliable methodology for such investigation and our objective is to quantify the heterogeneity of bone microstructure over an entire cross-section of bone using ArcGIS v 9.3 (ESRI). This was accomplished by identifying the distribution of remodeling units in a human metatarsal relative to bending axes. One biomechanical hypothesis suggests that collagen fiber orientation, manifested by patterns of birefringence, are indicative of mode of strain during formation. This study demonstrates that GIS can be used to investigate, describe, and compare such patterns through histological mapping.
Osteon population density (OPD) in cortical bone is known to be useful in estimating age at death... more Osteon population density (OPD) in cortical bone is known to be useful in estimating age at death. Cortical thickness has also been investigated though it has been met with varied results, and prior research has measured this manually, sometimes arbitrarily. Previous research from our lab demonstrated that when the femoral cortex was divided circumferentially into anterior, posterior, medial, and lateral quadrants, and radially into periosteal, middle, and endosteal thirds, a combination of the periosteal and middle thirds from the anterior and lateral quadrants produced the most accurate prediction model for estimating age at death (adjusted R2=0.907, p<0.000). This current research sought to examine cortical thickness, measured objectively, in the quadrants of the femur to see if their inclusion would increase the accuracy of estimating age at death.
Thirty complete cross-sections from modern cadaveric femora were used, 15 of each sex, ranging from 21–97 years. A custom MATLAB code was written to evaluate cortical thickness by measuring a series of lines between + 10% of the quadrant center, from the periosteal to endosteal border, each perpendicular to a tangent line based on a periosteal node.
Measurements of cortical thickness from the anterior and lateral quadrants did not significantly correlate with age at death, though normalized by total subperiosteal area, anterior cortical thickness did significantly correlate with age. Combining anterior cortical thickness with OPD from the regions mentioned above, neither increased nor decreased the predictive ability of the regression function (adjusted R2=0.907, p<0.000) to estimate age at death.
After attending this presentation, attendees will understand the current issues with histological... more After attending this presentation, attendees will understand the current issues with histological age estimation, and the effect that region of interest (ROI) size has on the relationship between osteon population density (OPD) and age-at-death estimation. This presentation will impact the forensic science community by demonstrating that the amount of bone sampled/analyzed in histological age assessment can have a profound impact on the ability to accurately estimate age-at-death. This will inform future histological research, resulting in higher quality forensic research and practice. As a complement to macroscopic aging methods, or when necessary macroscopic elements are damaged/absent, age can be estimated through histological examination of remodeling events in cortical bone. To date, the femoral midshaft has been the most commonly employed site for histological studies; however, a consensus is lacking on how much bone to analyze when quantifying remodeling, as existing methods employ ROIs that differ in size, number, and location. Recently, histological research at the femoral midshaft has proliferated due to the revival of the Ericksen femur collection as an active resource. The current study is a meta-analysis of three recent studies that provide a unique opportunity to assess the effect of ROI size on the relationship between OPD and age. All three studies analyzed here (Ingvoldstad1, Crowder/Dominguez2, and Gocha3 methods) primarily utilized the Ericksen collection, examined the anterior region of the femur, and quantified remodeling according to the same standard histological definitions. The Ingvoldstad method examined 200 individuals (97 males, 103 females), aged 30–97 years (average=71 years), all from the Ericksen collection; a fixed ROI size of 3.00 mm2 was used to quantify remodeling at eight anatomical and biomechanical locations around the femoral cortex, though only anterior data are analyzed here. The Crowder/Dominguez method examined 320 individuals (170 males, 150 females), aged 15–97 (average=66 years), 87% of which were from the Ericksen collection. This method used a topographic sampling strategy, separating a 5 mm wide section of the anterior femur into 10 columns and reading every other frame using a Merz reticule; this resulted in an average ROI size of 18.30 mm2, with an average of 9.52 mm2 of bone analyzed. The Gocha method examined only 30 individuals (15 male, 15 female), aged 21–97 years (average=59 years), 83% of which were from the Ericksen collection. This method examined remodeling over the entirety of the femoral midshaft, though only anterior octant and quadrant data are analyzed here; average octant ROI size was 41.82 mm2, average quadrant ROI size was 89.93 mm2. Statistical analyses were performed in SPSS 23. Kolmogorov-Smirnov tests demonstrated OPD values for all methods to be normally distributed (all p-values >0.070). The relationship between OPD and age was assessed through Pearson’s correlation coefficients, as well as the adjusted R2 value of linear regression predictive models; all of these statistical measures were statistically significant (all p-values <0.043). One author (VMD), who collected the majority of the data for the Crowder/Dominguez method, also performed interobserver error measures for the Ingvoldstad and Gocha studies, neither of which demonstrated significant differences between observers. The correlation coefficient for the Ingvoldstad method was R=0.143, and the adjusted R2=0.016, indicating OPD explained only 1.6% of the variation in age-at-death. The correlation coefficient for the Crowder/Dominguez method was R=0.681, and the adjusted R2=0.462, indicating OPD explained 46.2% of the variation in age-at-death. The correlation coefficient for the Gocha Octant method was R=0.907, and the adjusted R2=0.817, indicating OPD explained 81.7% of the variation in in age at death. For the Gocha Quadrant method, the correlation coefficient was R=0.918 and the adjusted R2=0.838, indicating OPD explained 83.8% of the variation in age at death. Results indicate that ROI size has a significant effect on the ability to predict age-at-death from histological remodeling. Examination of small, isolated ROIs is not recommended, as such an approach is more susceptible to random variation in variable distribution and can negatively affect interpretation. Instead, future studies should examine larger ROIs to maximize histological remodeling’s ability to predict age-at-death.
After attending this presentation, attendees will better understand the role of the anthropologis... more After attending this presentation, attendees will better understand the role of the anthropologist in the identification and repatriation processes of deceased migrants found along the US-Mexico border. This presentation will impact the forensic science community by highlighting how the role of an anthropologist varies in identification and repatriation processes depending on local and state laws and may extend well beyond skeletal analysis. Often law enforcement may be responsible for identification efforts while an anthropologist provides a report to a medical examiner, law enforcement agency, coroner, or Justice of the Peace (JP). In other circumstances, however, responsibility for identification may fall to the anthropologist. Depending on jurisdiction, these responsibilities vary with the anthropologist taking on new roles. These varied roles will be examined through a survey of three partner organizations of the Forensic Border Coalition (FBC): the Argentine Forensic Anthropology Team (EAAF), the Pima County Office of the Medical Examiner (PCOME), and the Forensic Anthropology Center at Texas State (FACTS). A generalized description of identification and repatriation processes is given for migrant deaths in Arizona, while case studies will be discussed to illustrate the complexities of these processes in Texas. The EAAF investigates migrant deaths along both sides of the US-Mexico border. Regarding cases of unidentified remains recovered in the US, EAAF facilitates the collection of family reference sample DNA for comparison to DNA samples from remains likely to correspond to migrants. When DNA analysis suggests an identification, the EAAF works with Forensic Data Banks on Missing Migrants or other mechanisms within the migrant’s country of origin to compare all antemortem and postmortem records to confirm an identification. The EAAF writes an identification report and works with the appropriate local US officials to legally recognize the identification. In recent years EAAF has helped identify 65 migrants who perished within the US. Repatriation is then handled by a Consulate’s office, overseen by the Foreign Affairs Ministry from the decedent's home county. In Arizona, forensic anthropological investigations of presumed migrants takes place at the PCOME. Between 2001 and 2013, the PCOME received the remains of 2,203 presumed migrants, and successfully identified 1,463. For cases requiring skeletal analysis, anthropologists at the PCOME construct both a biological and cultural profile. Once an identification hypothesis is made, the anthropologist compares all antemortem and postmortem data, writes an identification report, and briefs the Medical Examiner who legally signs off on an identification. If the decedent is to be returned to their country of origin, the local Consulate’s office manages the repatriation of the remains, a process that can take weeks to months. Since 2013, Operation Identification (OpID), housed within FACTS, has received the remains of 87 presumed migrants, many through exhumation efforts carried out by Baylor University and University of Indianapolis. DNA analysis, along with anthropological analyses of the skeletal remains and personal effects, are the primary sources for identification hypotheses. Once a DNA association is reported, anthropologists associated with OpID compare all antemortem and postmortem data, write an identification report, and brief the appropriate JP who legally approves the identification. Since 2014, OpID has helped facilitate nine identifications, however only five of those individuals have been successfully repatriated. The repatriation process for counties without a medical examiner requires the coordinated efforts of Consulate offices, the funeral home handling the repatriation, the funeral home that originally filed the death certificate, and the JP, which can all vary by case. Unlike the Arizona model where these efforts are centralized, in Texas these parties can be vastly separated by geography, culture, and available resources, which can result in a breakdown of communication and stagnation of the repatriation process. In the most egregious example, an individual identified by OpID in August 2014 has still not been repatriated as of July 2016. This unfortunate reality has led to anthropologists in Texas adopting new roles as de facto case managers and stewards of identification and repatriation processes. Anthropologists associated with OpID, with help from other FBC partners, are now facilitating/mediating communication between funeral homes, law enforcement, JPs, Medical Examiners, and the decedent’s family members. It is believed these expanded roles of the anthropologist will help streamline and hasten the repatriation of remains.
Brooks County in South Texas is part of a known migrant corridor used by undocumented border cros... more Brooks County in South Texas is part of a known migrant corridor used by undocumented border crossers entering Texas through the U.S./Mexico border. Operation Identification (OpID) at Texas State University is a project which aims to facilitate the identification and repatriation of human remains found along or near the South Texas border through scientific analysis and collaboration with governmental and nongovernmental organization. The project utilizes a multifaceted anthropological approach towards identification including traditional osteological, dental, isotopic, genetic, and histological analyses. Additionally, OpID incorporates biocultural lines of evidence not commonly used in biological anthropology such as analyses of missing persons reports for comparison of antemortem and postmortem data, and exmination of personal effects to help establish identification hypotheses. Since 2013, OpID has received a total of 195 sets of human remains or presumed migrants and has helped facilitate in the identification of 18 individuals.
Evidence of cancer’s long history in humans exists in the archeological record, though it is res... more Evidence of cancer’s long history in humans exists in the archeological record, though it is restricted to cases in which cancer either originated in or metastasized to bone. Skeletal lesions from metastasized carcinomas, however, are varied in appearance and make differential diagnosis from skeletal material difficult. Modern clinical diagnostic tools are of limited use in paleopathology because of their reliance on non-mineralized material (e.g. blood work, decalcified biopsies). As a result, skeletal references for confirmed cases of metastasized carcinomas are rare. The current case study presents a histological analysis of the rib and femoral metastases resulting from a primary diagnosis of breast cancer in a 27 year-old female. Multiple, undecalcified cross-sections from the femoral midshafts and various locations throughout the 6th ribs were examined under brightfield and polarized light microscopy. Overall, this individual presents with a mixed osteolytic and osteoblastic response, which is relatively uncommon in metastatic tumors of bone. The osteolytic response, observed only in the ribs, is primarily on the periosteal surface and extends moderately into the cortex. In contrast, the osteoblastic response primarily affected the endosteal border, resulting in a proliferation of woven-fibered bone highly disorganized in appearance. This indicates rapid deposition though some areas show evidence of incipient remodeling. This process is more marked in the rib, resulting in an almost complete infilling of the medullary area. Recognition of these patterns in a confirmed case of metastatic cancer may aid differential diagnosis in a paleopathological setting.
The repeatability, precision, and validity of anthropometric landmarks has been assessed in the c... more The repeatability, precision, and validity of anthropometric landmarks has been assessed in the context of the ectocranium, but few studies have examined the reproducibility of endocranial landmarks. This is due in part to the difficulty in accessing these landmarks. To evaluate the repeatability of registering endocranial landmarks with a digitizer, nineteen homologous landmarks (9 Type I, 10 Type II, 7 unpaired, 12 paired) defining the endocranial base were selected for analysis. Three observers digitized 15 anatomical specimens with a coordinate measuring machine over four measurement rounds with at least four days separating each round (180 configurations total). Significant effects on shape due to individual observer and digitization were found after a Procrustes fit of the coordinate data and subsequent Procrustes ANOVA (p < 0.0001). Observer error was 2.52 times greater than digitizing error and the smallest level of biological variation was 3.64 times greater than observer error. Patterns of variation in the levels of measurement error were explored with a principal components analysis of the covariance matrices for observer and digitization variables. The greatest shape changes were seen in anterior frontal, posterior frontal, and internal occipital protuberance landmarks, all Type II. This study is not a measure of individual landmark location; rather, it examines the effect of individual landmarks on mean shape. Thus, data collected from multiple observers of the endobasicranium may be combined into a single data set for further analyses and hypothesis testing of shape variation and covariance of landmarks, such as assessing patterns of modularity.
After attending this presentation, attendees will understand the spatial variation present in the... more After attending this presentation, attendees will understand the spatial variation present in the distribution of intracortical remodeling events throughout the entirety of the femoral midshaft, and the importance of selecting regions of interest (ROI) for developing new histological aging methods.
This presentation will impact the forensic science community by introducing new sampling strategies for the quantification of histological remodeling that can be used to estimate age, and further demonstrating these age estimates to be highly accurate throughout the adult life span.
As a complement to macroscopic aging methods, or when necessary macroscopic elements are damaged/absent, age can be estimated through histological examination of remodeling events in cortical bone. During the last half century the femoral midshaft has been the most commonly employed site for histological studies; however, a consensus is still lacking on where to best quantify remodeling, as different methods employ various ROIs that differ in size, number, and location. To address this knowledge gap, this study employed geographic information systems (GIS) software to digitally map all remodeling events (intact and fragmentary osteons, and resorptive bays) across the entirety of the femoral midshaft. Patterns in the spatial distribution of remodeling were then examined to identify which region(s) of the femoral cortex produce the most accurate age estimates.
Thirty complete cross-sections from modern cadaveric femora were used, 15 of each sex, ranging from 21–97 years (mean = 58.9; SD = 22.1 years), with both sexes having similar age distributions. Each sample was photographed under polarized light and seamless cross-sectional images were imported into ArcGIS v10.1. Polygon features were created to overlay cortical areas and all remodeling events (n = 230,870) were identified and digitally annotated with point features. A total of 10 different sampling strategies were employed, each subdividing the entire cortex in a different manner. Osteon population density (OPD) was calculated by summing all remodeling events within an ROI and dividing by its area.
Statistical analyses were performed in SPSS 21. OPD values were normally distributed for each ROI, and MANCOVA analyses revealed that OPD was not significantly different between sexes for any ROI, allowing the combination of male and female data for further analyses. Paired t-tests revealed OPD calculations were not statistically different between observers. Stepwise linear regression was used to determine which ROIs from each sampling strategy were most useful in estimating age. To further evaluate the performance of the resulting predictive models, jackknife age estimates were generated by removing an individual from the sample, recalculating the regression model, and then estimating the age of the individual not included in the model; this was done iteratively for all individuals. The accuracy of these estimates was analyzed through measures of bias and inaccuracy.
Results indicate the two most promising sampling strategies are dividing the femoral cortex into anterior, posterior, medial, and lateral (APML) quadrants separated into periosteal, middle, and endosteal thirds, and also APML octants separated into thirds. Stepwise regression selected four ROIs for each method, primarily in the lateral and anterolateral regions of the cortex, and spread between all depths of the cortex. The resulting model for the APML quadrants by thirds explains more than 90% of the variation in age (adj. R2 = 0.907, p = 0.000) with a standard error of 6.73 years, while the APML octants by thirds explained more than 93% of the variation in age (adj. R2 = 0.931, p = 0.000) with a standard error of 5.82 years. Jackknife age estimates from both models were very promising, with average differences between estimated and known age (bias) being less than one year and average absolute differences between estimated and known age (inaccuracy) being less than six years. Further, individuals in their 90s had bias and inaccuracy measures of less than seven and four years for the quadrants and octants methods, respectively. Such accuracy in age estimation, even into the tenth decade of life, demonstrates that this new method for histological aging considerably outperforms more traditional macroscopic methods of aging in older individuals. Considering increasing life expectancies, this research has great promise in providing forensic anthropologists a tool to accurately age elderly individuals.
The Forensic Anthropology Case Team (FACT) at The Ohio State University is a volunteer organizati... more The Forensic Anthropology Case Team (FACT) at The Ohio State University is a volunteer organization that serves the Ohio community by assisting law enforcement agencies, coroner’s offices, and local communities in searching for, recovering, and analyzing/identifying human remains. In March 2014 members of the FACT team, at the behest of local officials, analyzed a set of remains presenting with an interesting degree of differential decomposition.
The remains in question were discovered in a small wooded area near a homeless camp located in downtown Columbus, OH, and recovered by the local police department and coroner’s office, without help from anthropologists. Due to the degree of decomposition the analysis conducted by the local coroner’s office was inconclusive, at which point they requested the assistance of FACT personnel in analyzing the remains.
Taphonomically, the remains superior to and including the pelvic girdle were found to be in a state of advanced decomposition, where all elements present were mostly skeletonized, though still articulated with varied amounts of desiccated soft tissue; however, the upper limbs were completely absent. In contrast, the lower limbs were still fleshed and displayed marbling as well as skin slippage, indicating they were only in the bloat stage of decomposition.
The postmortem interval (PMI) was estimated using Megyesi et al. (2005), which accounts for the level of decomposition across body regions through calculation of a Total Body Score (TBS). The TBS calculated from the elements present (i.e. no upper limbs) resulted in a 95% prediction interval of the PMI to be sometime in the three months preceding the discovery of the remains. However, one might logically infer that if the upper limbs were present they would have more closely resembled the decompositional state of the trunk, head and neck, rather than the lower limbs. Therefore, a second TBS was calculated by averaging the assumed disparity in decomposition between the upper and lower limbs, which resulted in a 95% prediction interval of the PMI to extend one month further back than the original PMI calculation. Subsequent DNA analysis identified the remains, and the individual was known to have gone missing at a time only covered by the second PMI estimate that inferred the decompositional status of the missing upper limbs.
The differential decomposition from this case is explained by the lower limbs having been protected by denim jeans and tennis shoes, while such protection was seemingly absent for the upper body. This case study suggests that, when possible, it is important to consider missing skeletal elements when estimating PMI. It may also be of particular interest to others practicing forensic anthropology in the Midwestern United States, as they may also see remains subjected to similar environments.
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Thirty complete cross-sections from modern cadaveric femora were used, 15 of each sex, ranging from 21–97 years. A custom MATLAB code was written to evaluate cortical thickness by measuring a series of lines between + 10% of the quadrant center, from the periosteal to endosteal border, each perpendicular to a tangent line based on a periosteal node.
Measurements of cortical thickness from the anterior and lateral quadrants did not significantly correlate with age at death, though normalized by total subperiosteal area, anterior cortical thickness did significantly correlate with age. Combining anterior cortical thickness with OPD from the regions mentioned above, neither increased nor decreased the predictive ability of the regression function (adjusted R2=0.907, p<0.000) to estimate age at death.
This presentation will impact the forensic science community by demonstrating that the amount of bone sampled/analyzed in histological age assessment can have a profound impact on the ability to accurately estimate age-at-death. This will inform future histological research, resulting in higher quality forensic research and practice.
As a complement to macroscopic aging methods, or when necessary macroscopic elements are damaged/absent, age can be estimated through histological examination of remodeling events in cortical bone. To date, the femoral midshaft has been the most commonly employed site for histological studies; however, a consensus is lacking on how much bone to analyze when quantifying remodeling, as existing methods employ ROIs that differ in size, number, and location.
Recently, histological research at the femoral midshaft has proliferated due to the revival of the Ericksen femur collection as an active resource. The current study is a meta-analysis of three recent studies that provide a unique opportunity to assess the effect of ROI size on the relationship between OPD and age. All three studies analyzed here (Ingvoldstad1, Crowder/Dominguez2, and Gocha3 methods) primarily utilized the Ericksen collection, examined the anterior region of the femur, and quantified remodeling according to the same standard histological definitions.
The Ingvoldstad method examined 200 individuals (97 males, 103 females), aged 30–97 years (average=71 years), all from the Ericksen collection; a fixed ROI size of 3.00 mm2 was used to quantify remodeling at eight anatomical and biomechanical locations around the femoral cortex, though only anterior data are analyzed here. The Crowder/Dominguez method examined 320 individuals (170 males, 150 females), aged 15–97 (average=66 years), 87% of which were from the Ericksen collection. This method used a topographic sampling strategy, separating a 5 mm wide section of the anterior femur into 10 columns and reading every other frame using a Merz reticule; this resulted in an average ROI size of 18.30 mm2, with an average of 9.52 mm2 of bone analyzed. The Gocha method examined only 30 individuals (15 male, 15 female), aged 21–97 years (average=59 years), 83% of which were from the Ericksen collection. This method examined remodeling over the entirety of the femoral midshaft, though only anterior octant and quadrant data are analyzed here; average octant ROI size was 41.82 mm2, average quadrant ROI size was 89.93 mm2.
Statistical analyses were performed in SPSS 23. Kolmogorov-Smirnov tests demonstrated OPD values for all methods to be normally distributed (all p-values >0.070). The relationship between OPD and age was assessed through Pearson’s correlation coefficients, as well as the adjusted R2 value of linear regression predictive models; all of these statistical measures were statistically significant (all p-values <0.043). One author (VMD), who collected the majority of the data for the Crowder/Dominguez method, also performed interobserver error measures for the Ingvoldstad and Gocha studies, neither of which demonstrated significant differences between observers.
The correlation coefficient for the Ingvoldstad method was R=0.143, and the adjusted R2=0.016, indicating OPD explained only 1.6% of the variation in age-at-death. The correlation coefficient for the Crowder/Dominguez method was R=0.681, and the adjusted R2=0.462, indicating OPD explained 46.2% of the variation in age-at-death. The correlation coefficient for the Gocha Octant method was R=0.907, and the adjusted R2=0.817, indicating OPD explained 81.7% of the variation in in age at death. For the Gocha Quadrant method, the correlation coefficient was R=0.918 and the adjusted R2=0.838, indicating OPD explained 83.8% of the variation in age at death.
Results indicate that ROI size has a significant effect on the ability to predict age-at-death from histological remodeling. Examination of small, isolated ROIs is not recommended, as such an approach is more susceptible to random variation in variable distribution and can negatively affect interpretation. Instead, future studies should examine larger ROIs to maximize histological remodeling’s ability to predict age-at-death.
This presentation will impact the forensic science community by highlighting how the role of an anthropologist varies in identification and repatriation processes depending on local and state laws and may extend well beyond skeletal analysis.
Often law enforcement may be responsible for identification efforts while an anthropologist provides a report to a medical examiner, law enforcement agency, coroner, or Justice of the Peace (JP). In other circumstances, however, responsibility for identification may fall to the anthropologist. Depending on jurisdiction, these responsibilities vary with the anthropologist taking on new roles.
These varied roles will be examined through a survey of three partner organizations of the Forensic Border Coalition (FBC): the Argentine Forensic Anthropology Team (EAAF), the Pima County Office of the Medical Examiner (PCOME), and the Forensic Anthropology Center at Texas State (FACTS). A generalized description of identification and repatriation processes is given for migrant deaths in Arizona, while case studies will be discussed to illustrate the complexities of these processes in Texas.
The EAAF investigates migrant deaths along both sides of the US-Mexico border. Regarding cases of unidentified remains recovered in the US, EAAF facilitates the collection of family reference sample DNA for comparison to DNA samples from remains likely to correspond to migrants. When DNA analysis suggests an identification, the EAAF works with Forensic Data Banks on Missing Migrants or other mechanisms within the migrant’s country of origin to compare all antemortem and postmortem records to confirm an identification. The EAAF writes an identification report and works with the appropriate local US officials to legally recognize the identification. In recent years EAAF has helped identify 65 migrants who perished within the US. Repatriation is then handled by a Consulate’s office, overseen by the Foreign Affairs Ministry from the decedent's home county.
In Arizona, forensic anthropological investigations of presumed migrants takes place at the PCOME. Between 2001 and 2013, the PCOME received the remains of 2,203 presumed migrants, and successfully identified 1,463. For cases requiring skeletal analysis, anthropologists at the PCOME construct both a biological and cultural profile. Once an identification hypothesis is made, the anthropologist compares all antemortem and postmortem data, writes an identification report, and briefs the Medical Examiner who legally signs off on an identification. If the decedent is to be returned to their country of origin, the local Consulate’s office manages the repatriation of the remains, a process that can take weeks to months.
Since 2013, Operation Identification (OpID), housed within FACTS, has received the remains of 87 presumed migrants, many through exhumation efforts carried out by Baylor University and University of Indianapolis. DNA analysis, along with anthropological analyses of the skeletal remains and personal effects, are the primary sources for identification hypotheses. Once a DNA association is reported, anthropologists associated with OpID compare all antemortem and postmortem data, write an identification report, and brief the appropriate JP who legally approves the identification. Since 2014, OpID has helped facilitate nine identifications, however only five of those individuals have been successfully repatriated. The repatriation process for counties without a medical examiner requires the coordinated efforts of Consulate offices, the funeral home handling the repatriation, the funeral home that originally filed the death certificate, and the JP, which can all vary by case. Unlike the Arizona model where these efforts are centralized, in Texas these parties can be vastly separated by geography, culture, and available resources, which can result in a breakdown of communication and stagnation of the repatriation process. In the most egregious example, an individual identified by OpID in August 2014 has still not been repatriated as of July 2016.
This unfortunate reality has led to anthropologists in Texas adopting new roles as de facto case managers and stewards of identification and repatriation processes. Anthropologists associated with OpID, with help from other FBC partners, are now facilitating/mediating communication between funeral homes, law enforcement, JPs, Medical Examiners, and the decedent’s family members. It is believed these expanded roles of the anthropologist will help streamline and hasten the repatriation of remains.
Thirty complete cross-sections from modern cadaveric femora were used, 15 of each sex, ranging from 21–97 years. A custom MATLAB code was written to evaluate cortical thickness by measuring a series of lines between + 10% of the quadrant center, from the periosteal to endosteal border, each perpendicular to a tangent line based on a periosteal node.
Measurements of cortical thickness from the anterior and lateral quadrants did not significantly correlate with age at death, though normalized by total subperiosteal area, anterior cortical thickness did significantly correlate with age. Combining anterior cortical thickness with OPD from the regions mentioned above, neither increased nor decreased the predictive ability of the regression function (adjusted R2=0.907, p<0.000) to estimate age at death.
This presentation will impact the forensic science community by demonstrating that the amount of bone sampled/analyzed in histological age assessment can have a profound impact on the ability to accurately estimate age-at-death. This will inform future histological research, resulting in higher quality forensic research and practice.
As a complement to macroscopic aging methods, or when necessary macroscopic elements are damaged/absent, age can be estimated through histological examination of remodeling events in cortical bone. To date, the femoral midshaft has been the most commonly employed site for histological studies; however, a consensus is lacking on how much bone to analyze when quantifying remodeling, as existing methods employ ROIs that differ in size, number, and location.
Recently, histological research at the femoral midshaft has proliferated due to the revival of the Ericksen femur collection as an active resource. The current study is a meta-analysis of three recent studies that provide a unique opportunity to assess the effect of ROI size on the relationship between OPD and age. All three studies analyzed here (Ingvoldstad1, Crowder/Dominguez2, and Gocha3 methods) primarily utilized the Ericksen collection, examined the anterior region of the femur, and quantified remodeling according to the same standard histological definitions.
The Ingvoldstad method examined 200 individuals (97 males, 103 females), aged 30–97 years (average=71 years), all from the Ericksen collection; a fixed ROI size of 3.00 mm2 was used to quantify remodeling at eight anatomical and biomechanical locations around the femoral cortex, though only anterior data are analyzed here. The Crowder/Dominguez method examined 320 individuals (170 males, 150 females), aged 15–97 (average=66 years), 87% of which were from the Ericksen collection. This method used a topographic sampling strategy, separating a 5 mm wide section of the anterior femur into 10 columns and reading every other frame using a Merz reticule; this resulted in an average ROI size of 18.30 mm2, with an average of 9.52 mm2 of bone analyzed. The Gocha method examined only 30 individuals (15 male, 15 female), aged 21–97 years (average=59 years), 83% of which were from the Ericksen collection. This method examined remodeling over the entirety of the femoral midshaft, though only anterior octant and quadrant data are analyzed here; average octant ROI size was 41.82 mm2, average quadrant ROI size was 89.93 mm2.
Statistical analyses were performed in SPSS 23. Kolmogorov-Smirnov tests demonstrated OPD values for all methods to be normally distributed (all p-values >0.070). The relationship between OPD and age was assessed through Pearson’s correlation coefficients, as well as the adjusted R2 value of linear regression predictive models; all of these statistical measures were statistically significant (all p-values <0.043). One author (VMD), who collected the majority of the data for the Crowder/Dominguez method, also performed interobserver error measures for the Ingvoldstad and Gocha studies, neither of which demonstrated significant differences between observers.
The correlation coefficient for the Ingvoldstad method was R=0.143, and the adjusted R2=0.016, indicating OPD explained only 1.6% of the variation in age-at-death. The correlation coefficient for the Crowder/Dominguez method was R=0.681, and the adjusted R2=0.462, indicating OPD explained 46.2% of the variation in age-at-death. The correlation coefficient for the Gocha Octant method was R=0.907, and the adjusted R2=0.817, indicating OPD explained 81.7% of the variation in in age at death. For the Gocha Quadrant method, the correlation coefficient was R=0.918 and the adjusted R2=0.838, indicating OPD explained 83.8% of the variation in age at death.
Results indicate that ROI size has a significant effect on the ability to predict age-at-death from histological remodeling. Examination of small, isolated ROIs is not recommended, as such an approach is more susceptible to random variation in variable distribution and can negatively affect interpretation. Instead, future studies should examine larger ROIs to maximize histological remodeling’s ability to predict age-at-death.
This presentation will impact the forensic science community by highlighting how the role of an anthropologist varies in identification and repatriation processes depending on local and state laws and may extend well beyond skeletal analysis.
Often law enforcement may be responsible for identification efforts while an anthropologist provides a report to a medical examiner, law enforcement agency, coroner, or Justice of the Peace (JP). In other circumstances, however, responsibility for identification may fall to the anthropologist. Depending on jurisdiction, these responsibilities vary with the anthropologist taking on new roles.
These varied roles will be examined through a survey of three partner organizations of the Forensic Border Coalition (FBC): the Argentine Forensic Anthropology Team (EAAF), the Pima County Office of the Medical Examiner (PCOME), and the Forensic Anthropology Center at Texas State (FACTS). A generalized description of identification and repatriation processes is given for migrant deaths in Arizona, while case studies will be discussed to illustrate the complexities of these processes in Texas.
The EAAF investigates migrant deaths along both sides of the US-Mexico border. Regarding cases of unidentified remains recovered in the US, EAAF facilitates the collection of family reference sample DNA for comparison to DNA samples from remains likely to correspond to migrants. When DNA analysis suggests an identification, the EAAF works with Forensic Data Banks on Missing Migrants or other mechanisms within the migrant’s country of origin to compare all antemortem and postmortem records to confirm an identification. The EAAF writes an identification report and works with the appropriate local US officials to legally recognize the identification. In recent years EAAF has helped identify 65 migrants who perished within the US. Repatriation is then handled by a Consulate’s office, overseen by the Foreign Affairs Ministry from the decedent's home county.
In Arizona, forensic anthropological investigations of presumed migrants takes place at the PCOME. Between 2001 and 2013, the PCOME received the remains of 2,203 presumed migrants, and successfully identified 1,463. For cases requiring skeletal analysis, anthropologists at the PCOME construct both a biological and cultural profile. Once an identification hypothesis is made, the anthropologist compares all antemortem and postmortem data, writes an identification report, and briefs the Medical Examiner who legally signs off on an identification. If the decedent is to be returned to their country of origin, the local Consulate’s office manages the repatriation of the remains, a process that can take weeks to months.
Since 2013, Operation Identification (OpID), housed within FACTS, has received the remains of 87 presumed migrants, many through exhumation efforts carried out by Baylor University and University of Indianapolis. DNA analysis, along with anthropological analyses of the skeletal remains and personal effects, are the primary sources for identification hypotheses. Once a DNA association is reported, anthropologists associated with OpID compare all antemortem and postmortem data, write an identification report, and brief the appropriate JP who legally approves the identification. Since 2014, OpID has helped facilitate nine identifications, however only five of those individuals have been successfully repatriated. The repatriation process for counties without a medical examiner requires the coordinated efforts of Consulate offices, the funeral home handling the repatriation, the funeral home that originally filed the death certificate, and the JP, which can all vary by case. Unlike the Arizona model where these efforts are centralized, in Texas these parties can be vastly separated by geography, culture, and available resources, which can result in a breakdown of communication and stagnation of the repatriation process. In the most egregious example, an individual identified by OpID in August 2014 has still not been repatriated as of July 2016.
This unfortunate reality has led to anthropologists in Texas adopting new roles as de facto case managers and stewards of identification and repatriation processes. Anthropologists associated with OpID, with help from other FBC partners, are now facilitating/mediating communication between funeral homes, law enforcement, JPs, Medical Examiners, and the decedent’s family members. It is believed these expanded roles of the anthropologist will help streamline and hasten the repatriation of remains.
Multiple, undecalcified cross-sections from the femoral midshafts and various locations throughout the 6th ribs were examined under brightfield and polarized light microscopy. Overall, this individual presents with a mixed osteolytic and osteoblastic response, which is relatively uncommon in metastatic tumors of bone. The osteolytic response, observed only in the ribs, is primarily on the periosteal surface and extends moderately into the cortex. In contrast, the osteoblastic response primarily affected the endosteal border, resulting in a proliferation of woven-fibered bone highly disorganized in appearance. This indicates rapid deposition though some areas show evidence of incipient remodeling. This process is more marked in the rib, resulting in an almost complete infilling of the medullary area. Recognition of these patterns in a confirmed case of metastatic cancer may aid differential diagnosis in a paleopathological setting.
This presentation will impact the forensic science community by introducing new sampling strategies for the quantification of histological remodeling that can be used to estimate age, and further demonstrating these age estimates to be highly accurate throughout the adult life span.
As a complement to macroscopic aging methods, or when necessary macroscopic elements are damaged/absent, age can be estimated through histological examination of remodeling events in cortical bone. During the last half century the femoral midshaft has been the most commonly employed site for histological studies; however, a consensus is still lacking on where to best quantify remodeling, as different methods employ various ROIs that differ in size, number, and location. To address this knowledge gap, this study employed geographic information systems (GIS) software to digitally map all remodeling events (intact and fragmentary osteons, and resorptive bays) across the entirety of the femoral midshaft. Patterns in the spatial distribution of remodeling were then examined to identify which region(s) of the femoral cortex produce the most accurate age estimates.
Thirty complete cross-sections from modern cadaveric femora were used, 15 of each sex, ranging from 21–97 years (mean = 58.9; SD = 22.1 years), with both sexes having similar age distributions. Each sample was photographed under polarized light and seamless cross-sectional images were imported into ArcGIS v10.1. Polygon features were created to overlay cortical areas and all remodeling events (n = 230,870) were identified and digitally annotated with point features. A total of 10 different sampling strategies were employed, each subdividing the entire cortex in a different manner. Osteon population density (OPD) was calculated by summing all remodeling events within an ROI and dividing by its area.
Statistical analyses were performed in SPSS 21. OPD values were normally distributed for each ROI, and MANCOVA analyses revealed that OPD was not significantly different between sexes for any ROI, allowing the combination of male and female data for further analyses. Paired t-tests revealed OPD calculations were not statistically different between observers. Stepwise linear regression was used to determine which ROIs from each sampling strategy were most useful in estimating age. To further evaluate the performance of the resulting predictive models, jackknife age estimates were generated by removing an individual from the sample, recalculating the regression model, and then estimating the age of the individual not included in the model; this was done iteratively for all individuals. The accuracy of these estimates was analyzed through measures of bias and inaccuracy.
Results indicate the two most promising sampling strategies are dividing the femoral cortex into anterior, posterior, medial, and lateral (APML) quadrants separated into periosteal, middle, and endosteal thirds, and also APML octants separated into thirds. Stepwise regression selected four ROIs for each method, primarily in the lateral and anterolateral regions of the cortex, and spread between all depths of the cortex. The resulting model for the APML quadrants by thirds explains more than 90% of the variation in age (adj. R2 = 0.907, p = 0.000) with a standard error of 6.73 years, while the APML octants by thirds explained more than 93% of the variation in age (adj. R2 = 0.931, p = 0.000) with a standard error of 5.82 years. Jackknife age estimates from both models were very promising, with average differences between estimated and known age (bias) being less than one year and average absolute differences between estimated and known age (inaccuracy) being less than six years. Further, individuals in their 90s had bias and inaccuracy measures of less than seven and four years for the quadrants and octants methods, respectively. Such accuracy in age estimation, even into the tenth decade of life, demonstrates that this new method for histological aging considerably outperforms more traditional macroscopic methods of aging in older individuals. Considering increasing life expectancies, this research has great promise in providing forensic anthropologists a tool to accurately age elderly individuals.
The remains in question were discovered in a small wooded area near a homeless camp located in downtown Columbus, OH, and recovered by the local police department and coroner’s office, without help from anthropologists. Due to the degree of decomposition the analysis conducted by the local coroner’s office was inconclusive, at which point they requested the assistance of FACT personnel in analyzing the remains.
Taphonomically, the remains superior to and including the pelvic girdle were found to be in a state of advanced decomposition, where all elements present were mostly skeletonized, though still articulated with varied amounts of desiccated soft tissue; however, the upper limbs were completely absent. In contrast, the lower limbs were still fleshed and displayed marbling as well as skin slippage, indicating they were only in the bloat stage of decomposition.
The postmortem interval (PMI) was estimated using Megyesi et al. (2005), which accounts for the level of decomposition across body regions through calculation of a Total Body Score (TBS). The TBS calculated from the elements present (i.e. no upper limbs) resulted in a 95% prediction interval of the PMI to be sometime in the three months preceding the discovery of the remains. However, one might logically infer that if the upper limbs were present they would have more closely resembled the decompositional state of the trunk, head and neck, rather than the lower limbs. Therefore, a second TBS was calculated by averaging the assumed disparity in decomposition between the upper and lower limbs, which resulted in a 95% prediction interval of the PMI to extend one month further back than the original PMI calculation. Subsequent DNA analysis identified the remains, and the individual was known to have gone missing at a time only covered by the second PMI estimate that inferred the decompositional status of the missing upper limbs.
The differential decomposition from this case is explained by the lower limbs having been protected by denim jeans and tennis shoes, while such protection was seemingly absent for the upper body. This case study suggests that, when possible, it is important to consider missing skeletal elements when estimating PMI. It may also be of particular interest to others practicing forensic anthropology in the Midwestern United States, as they may also see remains subjected to similar environments.