Biorchaeology

Several lines of bioarchaeological research have confirmed the gradual decline in lower limb loading among past human populations, beginning with the transition to agriculture. The goal of this study was to assess whether human tibial curvature reflects this decline, with a special emphasis on the time-span during which the pace of technological change has been the most rapid. Our study is the first (1) to apply longitudinal curvature analysis in the antero-posterior (A–P) and medio-lateral (M–L) planes to the human tibia, and (2) that incorporates a broad temporal population sample including the periods of intensification of agriculture, urbanization and industrialization (from 2900 BC to the 21st century AD; N = 435) within Czech territories. Using three-dimensional geometric morphometrics, we investigated whether anterior tibial curvature mirrors assumed diminishing lower limb loading between prehistoric and industrialized societies and explored its shape in all three dimensions....

The fibula transmits loads within the lower limb of hominids. The few studies of variation in the cross-sectional geometric (CSG) properties of the fibula have established differences in its rigidity among groups engaged in distinct habitual loading activities. This study adds to this research by considering the relationship between CSG properties and the anatomical position of the fibula relative to the tibia among groups with differences in documented activity patterns. We used pQCT scans taken at 50% of the length of the lower leg in 83 healthy young adult collegiate-aged individuals divided into five activity groups: runners, swimmers, cricketers, field hockey players, and non-athletes. We compared variation in calculated CSG properties against the distance between fibular and tibial centroids, as well as the angle of that plane relative to the plane of tibial Imax . Tibial and fibular CSG properties vary with respect to the relative position of the two bones. Tibial CSG propert...

The intensification of agriculture is often associated with declining mobility and bone strength through time, although women often exhibit less pronounced trends than men. For example, previous studies of prehistoric Central European agriculturalists (~5300 calibrated years BC to 850 AD) demonstrated a significant reduction in tibial rigidity among men, whereas women were characterized by low tibial rigidity, little temporal change, and high variability. Because of the potential for sex-specific skeletal responses to mechanical loading and a lack of modern comparative data, women's activity in prehistory remains difficult to interpret. This study compares humeral and tibial cross-sectional rigidity, shape, and interlimb loading among prehistoric Central European women agriculturalists and living European women of known behavior (athletes and controls). Prehistoric female tibial rigidity at all time periods was highly variable, but differed little from living sedentary women on ...

This study offers a combined analysis of longbone mechanical properties (cross-sectional geometry, CSG), upper-limb enthesopathies (entheseal changes, ECs), and external auditory exostoses (EAEs) among Neolithic people from Liguria (Italy). Previous CSG studies have suggested a high degree of mobility in mountainous terrain and sexual dimorphism in the upper limbs, with males being more oriented toward unimanual activities and females performing strenuous bimanual tasks. The aims of the study were to: 1) increase the sample size of the CSG analysis via the acquisition of surface 3D models, 2) provide a solid chronological framework through direct dating in order to allow for subsampling of individuals dated to the Impresso-Cardial Complex (ICC, c. 5800–5000 BCE) and the Square-Mouthed Pottery culture (c. 5000–4300 BCE), 3) integrate the results of CSG analysis with information on ECs of the humeral epicondyles, and 4) assess possible marine activities through analysis of EAEs. Resul...

Assessment of skeletal robusticity is an important tool for the archaeologist and anthropologist, since it may be related to the intensity and type of activity performed by ancient population groups. Development of computed tomography (CT) allows determination of biomechanical properties of long bones. However, CT technology may not be easily available and is a relatively expensive procedure. Therefore, it is pertinent to estimate whether any of the parameters which can be easily measured in bare bones by simple anthropometry are useful to assess the torsional strength and bending strength of these bones. We included twenty one well preserved tibiae corresponding to prehispanic adult individuals (13 men) of El Hierro. These bones were anthropometrically measured following classical methods, and also subjected to CT analysis, and further calculation of minimum and maximum second moments and polar second moment of area, both at midshaft and at the nutrient foramen levels, using the so...

Several lines of bioarchaeological research have confirmed the gradual decline in lower limb loading among past human populations, beginning with the transition to agriculture. The goal of this study was to assess whether human tibial curvature reflects this decline, with a special emphasis on the time-span during which the pace of technological change has been the most rapid. Our study is the first (1) to apply longitudinal curvature analysis in the antero-posterior (A-P) and medio-lateral (M-L) planes to the human tibia, and (2) that incorporates a broad temporal population sample including the periods of intensification of agriculture, urbanization and industrialization (from 2900 BC to the 21 st century AD; N = 435) within Czech territories. Using three-dimensional geometric morphometrics, we investigated whether anterior tibial curvature mirrors assumed diminishing lower limb loading between prehistoric and industrialized societies and explored its shape in all three dimensions. Results showed the continuous trend of A-P straightening of the shaft. This straightening was associated with a relative sigmoidal curve accentuation in the M-L plane. Given the timescale involved and the known phenomenon of declining mobility, such adaptive changes in bone geometry can be interpreted in terms of the diminishing biomechanical demands on the tibia under different living conditions.

Se detalla parte de las actividades realizadas durante el año 2012 en el marco
de un proyecto de conservación en el Área de Antropología Biológica del Museo
Etnográfico J. B. Ambrosetti, Universidad de Buenos Aires, Argentina. Este Plan Integral de Manejo de Colecciones Osteológicas se propone desarrollar un protocolo basado en el tratamiento ético de los restos humanos, destacándose los conceptos
de custodia, identidad y respeto, que cubre aspectos articulados en cuatro ejes
principales: ética, educación/investigación, conservación y patrimonio. Dentro de ese
marco, se discuten los procedimientos específicos implementados tendientes a la
salvaguarda y minimización del deterioro de un conjunto de restos humanos
afectados por agentes medioambientales. Se enfatiza en la interacción entre
especialistas de diferentes disciplinas para desarrollar tareas de conservación desde
una perspectiva integradora. Esta forma de abordar las colecciones establece nuevas
estrategias que contemplan la necesidad de desarrollar tareas de conservación y
analizar la información científica en un marco que priorice los aspectos bioéticos
de las políticas de manejo patrimonial. Los resultados son prometedores para la
caracterización de las colecciones, lo cual incluye la identificación, documentación,
conservación y guarda de restos humanos prehistóricos procedentes de diferentes
regiones del mundo. La aplicación de esta propuesta surge desde la bioantropología
para abordar las investigaciones de restos humanos desde una perspectiva integral.
Se pretende contribuir a generar conciencia entre los investigadores de restos humanos sobre la importancia de su participación en la generación de protocolos de conservación.

It has been hypothesised that limb tapering refl ects an energetic trade-off between bone strength and weight, and selection for tissue economy, resulting in lighter distal limb segments. If adaptive mechanisms constrain the response of osseous tissue to mechanical loading one might expect a higher level of constraint, and therefore less variability, in more distal aspects of the limb. High-resolution CT was used to quantify the distribution and variation in strength (Zp), cortical area (CA) and shape (Imax/Imin) at 5 % intervals along the femoral and tibial diaphysis for a skeletal sample of mid- to late Holocene Native American agriculturalists and  foragers ( M = 21, F = 19). Z p and CA are highest in the proximal femur, decrease at a fairly consistent rate ( Z p increases in the distal femur) and reach their lowest values
at the distal tibia. By contrast, inherent morphological variability (coefficient of variation) for both Z p and CA are relatively constant along both the femur and tibia. The distribution and variation in I max / I min is greater than that of CA or Zp . These fi ndings
support earlier studies that have identified tapering in human limbs, yet, because morphological plasticity appears to be generally consistent across the diaphyses of the femur and tibia, morphological constraint (canalisation) does not seem to be the
overriding mechanism dictating the tapering of limb bone structure.

In this chapter we investigate the lower limb structural rigidity (using cross-sectional geometric properties of the diaphyseal midshaft) within a sample of 124 individuals from the Late Upper Paleolithic, Neolithic and Iron Age from Italy, Medieval Germany, and twenty-first Century Britain (long distance runners, field hockey players, and sedentary controls). Late Upper Paleolithic, Neolithic and Iron Age samples were settled in rugged areas, whereas the other samples inhabited plain areas. The aim of this study is to assess whether fibular diaphyseal properties reflect mobility patterns or terrain properties in past populations. Both fibular rigidity and relative fibular rigidity ratio (fibula/tibia) have been analyzed. Results reveal that Late Upper Paleolithic, Neolithic and Iron Age samples show high fibular rigidity and have values of relative fibular rigidity that are most similar to modern hockey players. The relative fibular diaphyseal rigidity of hockey players has been previously explained as the consequence of their dynamic and repetitive change of direction. Late Upper Paleolithic and Neolithic individuals are thought to have been highly terrestrially mobile, while Iron Age people were probably fairly sedentary. However, all of the three groups lived in areas of uneven terrain. We concluded that fibular rigidity and relative fibular rigidity are influenced by factorsthat increase foot eversion/inversion such as frequent directional changes and uneven terrain. The results of this study suggest that inclusion of the fibula provides a valuable additional perspective that complements traditional predictions of mobility patterns based on the femur or the tibia alone.

Preface
For decades, scientists have relied on the concept of mobility in describing activity patterns of past and present human populations.  Population-level comparisons have traditionally sought to demonstrate differential mobility (e.g., logistical or residential) amongst Pleistocene or Holocene Homo groups, using this as a basis for inferring convergent or contrasting adaptive behavior.  For example, shifting from a hunter-gatherer to a more sedentary agricultural subsistence strategy generally has been associated with a relative decline in mobility associated with the latter.  Substantial efforts have been devoted towards inferring which musculoskeletal adaptations best reflect such a potential shift in mobility.  The central role of bipedalism in human locomotion predisposes lower limb musculoskeletal anatomy to feature prominently in these inferences, although it is important to note that expressions of mobility in other areas of the postcranium (e.g., the upper limb) are gaining traction in the field when studying select populations (e.g., coastal or island groups).  It is problematic that often mobility is not defined a priori in precise enough terms to facilitate comparability of results across studies.  Typically, some derivation of an ethnographic definition of mobility is adopted, whether explicitly recognized or not (e.g., populations with greater mobility travel farther than populations with lesser mobility).  Usually, in applying the ethnographic definition, unstated motivations for travel focus on resource acquisition or intergroup relationships (e.g., trading).
On the other hand, an excessively narrow application of the concept of mobility, such as a mechanically-focused one, equally limits comparisons of results across studies.  Not all studies would (nor should) integrate experimental approaches in order to quantify mobility.  Resources necessary for the requisite acquisition of ground reaction force and kinematic data are not equally available to all researchers, and there are ethical and logistical constraints when studying human subjects.  Rather, the optimal solution for defining mobility, or fully capturing its essence, should embrace a multidisciplinary approach in how the concept is applied.  Despite such a long-standing and widespread reliance on the concept of mobility for reconstructing and comparing activity patterns and life histories of human populations, such an inclusive attempt at defining mobility has not yet been made.
To address this notable absence, in the spring of 2011, we organized a symposium on mobility at the 80th Annual Meeting of the American Association of Physical Anthropologists held in Minneapolis, MN.  The symposium assembled an array of experts using different approaches for quantifying and comparing the effects of mobility on postcranial musculoskeletal anatomy.  The symposium, and subsequent discussions, were aimed at embracing current perspectives and stimulating new ones that emphasized a holistic view of the interaction among intrinsic (i.e. skeletal) and extrinsic (i.e. environmental) factors relevant for quantifying and studying differential expression of mobility. Moreover, the symposium highlighted the importance of disentangling environmental effects some of which transcend traditional categorical groupings, such as coastal versus inland and/or mountainous versus flat terrain environments.
This volume emanates from the original symposium.  It is not intended to be the final word on the concept of mobility, but we hope that it will serve as a suitable starting point from which new discussion and future work can begin (or continue), perhaps with a renewed focus on critical issues identified herein or to be expanded laterally.  We also hope that this volume represents a useful advance by articulating a consensus working definition of mobility that can be widely applied in anthropological studies in order to overcome the lack of consistency in explicitly defining the concept of mobility that currently cripples the comparisons of results across studies.
There are a number of people we would like to thank, for this volume would not have materialized without the substantial efforts of many.  First, we would like to acknowledge the original participants in the 2011 symposium, not all of whom were able to contribute chapters to the volume for one reason or another.  The discussions that took place leading up to, during, and following the symposium helped shape this volume considerably.  Thank you for your contributions in driving this effort forwards.  We also would like to thank contributors to the volume who did not participate in the 2011 symposium for one reason or another.  Your contributions to the collective effort have broadened its scope in new, exciting ways.  Chapters were reviewed by a mix of fellow contributors, co-editors, and additional colleagues.  We are indebted to everyone who assisted with reviewing the individual chapters.  Thank you for your time and willingness to offer constructive suggestions.  Finally, we would like to thank Janet Slobodien, Jacob Gallay, and others at Springer Press for encouraging the efforts that ultimately led to this volume.  We are extremely grateful for this unwavering support throughout the entire process.

"During hominin plantigrade locomotion, the weight-bearing function of the fibula has been considered negligible. Nevertheless, studies conducted on human samples have demonstrated that, even if less than that of the tibia, the load-bearing function of the fibula still represents a considerable portion of the entire load borne by the leg. The present study assesses whether variation in habitual lower limb loading
influences fibular morphology in a predictable manner. To achieve this, both fibular and tibial morphology were compared amongst modern human athletes (field hockey players and cross-country runners) and matched sedentary controls. Peripheral quantitative computed tomography was used to
capture two-dimensional, cross-sectional bone images. Geometric properties were measured at the midshaft for each bone. Results show a trend of increased fibular rigidity from control to runners through to field hockey players. Moreover, relative fibular robusticity (fibula/tibia) is significantly greater in
hockey players compared with runners. These results are likely the consequence of habitual loading patterns performed by these athletes. Specifically, the repeated directional changes associated with field hockey increase the mediolateral loading on the lower leg in a manner that would not necessarily be
expected during cross-country running. The present study validates the use of the fibula in association with the tibia as a mean to provide a more complete picture of leg bone functional adaptations. Therefore, the fibula can be added to the list of bones generally used (tibia and femur) to assess the correspondence between mobility patterns and skeletal morphology for past human populations."

Previous research on the transition from hunting and gathering to production economy has suggested some general trends in past populations, i.e. decreased diaphyseal robusticity, increased cross-sectional circularity and decreased sexual dimorphism in the lower limb bones (femur and tibia), generally explained as a consequence of decreased levels of mobility. Previous results from the study of the Ligurian Neolithic populations from North-Western Italy (6th millennium BP) provide an exception to these trends. In particular, the Ligurian Neolithic lower limb robusticity and diaphyseal shape reflect high levels of terrestrial mobility throughout a rugged terrain. These results argue in favour of the growing consensus that the Neolithic transition was a region-specific process. In this work we expand the sample to include remains from caves from the same area, all within the same pastoral system, and extend the analysis to include the fibula. These new results show that the diaphyseal morphology of the Ligurian sample is more similar to highly mobile European Late Upper Palaeolithic and Mesolithic populations. Furthermore, the degree of sexual dimorphism for mechanical properties indicates behavioural differences between sexes, with males being more mobile than females. The results found here also indicate that inclusion of the fibula may contribute to a better understanding of past population mobility especially when it is considered in association with the tibia.

Cross-sectional geometrical (CSG) properties of an Iron Age Samnite group from Alfedena necropolis (Abruzzo, Italy, 2600-2400 B.P) are compares with a Ligurian Neolithic sample (6000-5500 B.P). In the period under examination, Samnites were organized in a tribal confederation led by patrilinear aristocracies, indicating incipient social stratification. In comparison, Neolithic society lacked clear signs of social hierarchy. The subsistence of both groups was mainly based on pastoralism and agriculture, but changes in habitual behavior are expected due to the socio-economic transformations that characterized the Iron Age. The Samnites’ warlike ideology suggests that unimanual weapon-use and training would have become frequent for males. The intensification of agriculture and the adoption of transhumant pastoralism, performed by a smaller subset of the population, likely led to a lower average level of logistic mobility. The strongly genderized ideology of the period suggests a strict sexual division pof labor, with women primarily performing sedentary tasks. CSG properties based on periosteal contours were calculated for humeri, femora, and tibiae (N = 61). Results corroborated the expectations: Alfedena males show substantial humeral bilateral asymmetry, indicating prevalent use of one arm, likely due to weapon training. In both sexes lower limb results indicate reduced obility with respect to the Neolithic group. Sexual dimorphism is significant in both humeral asymmetry and lower limb indicators of mobility. Although both groups could be broadly defined as agropastoral based on archaeological and historical evidence, CSG analysis confirmed important differences in habitual behavior.

"Estimates of muscle and other soft tissue properties derived from hominin skeletal and fossil remains would greatly enhance descriptions of body size and shape, and prior physical and metabolic capabilities. Presently, the utility of this approach is uncertain given the complex nature of the relationship between
muscle and bone. To address various principal issues, peripheral quantitative computed tomography (pQCT) imaging was used to quantify these relationships at the midshaft of the arm, forearm, and lower leg of modern human athletes (runners, field hockey players, swimmers, and cricketers) and control
subjects. Given the presumed behavior patterns of prehistoric hominins, the inclusion of highly active human participants was required. Soft tissue and muscle area was compared with bone area, diaphyseal shape, and torsional rigidity. Relationships were found between muscle area and bone area in the arm,
and muscle area and torsional rigidity in the forearm. However, the high standard error and prediction error that define these relationships indicate that muscle or other soft tissue predictions derived from hominin fossil or skeletal remains would be untenable. In the tibia, the relationship between soft tissue
properties and bone properties were primarily explained by covariation with body size. While the strength of the muscle-bone relationships in the arm and forearm vary among athletes and control subgroups, it appears that habitual upper limb loading performed throughout adolescence neither
strengthens nor weakens this relationship. Future attempts to estimate soft tissue properties from osseous tissue may be improved through the use of medical CT or MRI to image complete limb segments and isolate individual muscles."

"Variation in femoral and tibial diaphyseal
shape is used as an indicator of adaptation to patterns
of terrestrial mobility. Recent experimentation has
implied that lower limb diaphyseal shape may be primarily
influenced by lower limb length, and less so by
mobility patterns. If valid, this would, at most, render
previous interpretations of mobility patterns based on
analyses of diaphyseal shape questionable, and, at least,
require additional standardization that considers the
influence of limb length. Although the consequences
could be profound, this implication has yet to be directly
tested. Additionally, the influence of body breadth on tibial
shape (and to a lesser extent femoral shape) remains
uncertain. Tibial and femoral cross-sectional midshaft
shape measurements, taken from nine Pleistocene and
Holocene skeletal populations, were compared against
lower limb length, limb segment length, and bi-iliac
breadth. Generally, limb length and limb segment length
do not significantly influence femoral or tibial midshaft
shape. After controlling for body mass greater bi-iliac
breadth is associated with a relative mediolateral
strengthening of the femoral midshaft, while the influence
of a wider body shape (BIB/length) is associated
with a relative M-L strengthening of the tibia and femur
of males, and the tibia of females. We conclude that; (1)
mechanical interpretations of lower limb diaphyseal
shape are most parsimonious due to the lack of evidence
for a consistent relationship between segment length
and shape; however, (2) further work is required to
investigate the influence of bi-iliac breadth on both femoral
and tibial midshaft shape."

"The purpose of this article is to investigate
temporal shifts in skeletal robusticity to infer behavioral
changes in two populations (Neolithic, NEOL
and Medieval, MED) settled in the same geographic area
but involved in different subsistence economies (pastoralism
and coastal resources exploitation). This comparison
allows us to test the hypothesis that occupational
stress and mobility in the same environment produce
predictable changes in the robusticity of both upper and
lower limbs. Results show a lower degree of humeral
robusticity and a similar degree of humeral asymmetry
in the two sexes in the MED population. These results
are consistent with the relatively less stressful subsistence
economy documented in the MED population relative
to that of the NEOL. Lower limb results suggest that femoral robusticity does not correlate directly with the level of logistical mobility, but is instead due to the summation of several diverse factors that place biomechanical loads on the hindlimb, particularly unevenness of the terrain. However, female femoral gracility seems to indicate that below a certain ‘‘threshold’’ of mobility, i.e., movement over the natural terrain, terrain conformation is no longer the main contributing factor to femoral robusticity. The femoral shape index Ix/Iy declines through time, particularly in males. This agrees with
the expected mobility of the samples based on archaeological
and historical data, providing further evidence on the reliability of this index in inferring terrestrial mobility."