Search

In cross-sectional geometric (CSG) studies, both the subperiosteal and endosteal contours are considered important factors in determining bone bending rigidity. Recently, regression equations predicting CSG properties from a section's external dimensions were developed in a world-wide sample of human long bones. The results showed high correlations between some subperiosteally derived and actual CSG parameters. We present a theoretical model that further explores the influence of endosteal dimensions on CSG properties. We compare two hypothetical femoral midshaft samples with the same total subperiosteal area but with percentages of cortical bone at the opposite ends of published human variation for population sample means. Even in this relatively uncommon scenario, the difference between the samples in the resultant means for predicted femoral polar second moment of area (J) appears to be modest: power analysis indicates that a minimum sample size of 61 is needed to detect the difference 90% of the time via a t-test. Moreover, endosteal area can be predicted--although with substantial error--from periosteal area. Despite this error, including this relationship in subperiosteally derived estimates of J produces sample mean estimates close to true mean values. Power analyses reveal that when similar samples are used to develop prediction equations, a minimum sample of hundreds or more may be needed to distinguish a predicted mean J from the true mean J. These results further justify the use of regression equations estimating J from periosteal contours when analyzing behaviorally induced changes in bone rigidity in ancient populations, when it is not possible to measure endosteal dimensions. However, in other situations involving comparisons of individual values, growth trends, and senescence, where relative cortical thickness may vary greatly, inclusion of endosteal dimensions is still important. Am J Phys Anthropol 143:612-624, 2010. [c] 2010 Wiley-Liss, Inc. KEY WORDS bone mechanical properties; periosteal CSG; external dimensions DOI 10.1002/ajpa.21361

The growth, development, and maintenance of bone are influenced by genetic and environmental variables. Understanding variability in bone microstructure among primates may help illuminate the factors influencing the number and size of secondary osteons. The purpose of this study is to assess the bone microstructure in 8 humeral and 12 femoral sections of 12 juvenile chimpanzees, aged 2-15.3 years, and one adult chimp. Secondary osteons were counted and measured for 16 fields per section. Results indicate that the femur exhibits a mean osteon population density (OPD) of 4.46 [+ or -] 2.34/[mm.sup.2], mean Haversian canal area of 0.0016 [+ or -] 0.0007 [mm.sup.2], and mean osteon area of 0.033 [+ or -] 0.006 [mm.sup.2]. The humerus has a mean OPD of 4.72 [+ or -] 1.57/[mm.sup.2], mean Haversian canal area of 0.0013 [+ or -] 0.0003 [mm.sup.2], and mean osteon area of 0.033 [+ or -] 0.005 [mm.sup.2]. Differences are not significant between the humerus and femur, possibly indicating similar mechanical demands during locomotion. Osteon population density exhibits a moderate correlation with age (r = 0.498) in the femur of the juvenile chimps, but the adult chimp has an OPD of 10.28/[mm.sup.2], suggesting that osteons likely accumulate with age. Females exhibit higher osteon densities in the periosteal envelope compared to males in the humerus, indicating more remodeling during periosteal expansion. Overall similarities between chimpanzees and humans as well as previously published data on Late Pleistocene hominids (Abbott et al.: Am J Phys Anthropol 99 [1996] 585-601) suggest that bone microstructure has been stable throughout human evolution. KEY WORDS osteon; Hominoidea; histomorphometry; primate

This study attempts to fill a persistent gap in the literature by documenting the timing of epiphyseal union at the vertebral end of the ribs in a sample of modern Portuguese skeletons. The skeletal remains of 53 females and 45 males, between the ages of 11 and 30, were taken from the Lisbon documented skeletal collection. Individuals in the sample have been previously described as being representative of a middle-to-low socioeconomic segment of the early 20th century Lisbon population. Three anatomical locations were examined for epiphyseal union: the head, the articular tubercle and the nonarticular tubercle. The first epiphysis to show partial union is that of the nonarticular tubercle (females, 11-19 years; males, 11-19 years), followed by the epiphysis of the articular tubercle (females, 11-20 years; males, 16-20 years), and finally by the head epiphysis (females, 15-24 years; males, 16-22 years), which can still show incomplete epiphyseal closure at 25 and 24 years for females and males, respectively. A trend for earlier female maturation was observed, but the statistical tests only confirmed this result for some ribs and age groups. No directional asymmetry was found, but a significant fluctuating asymmetry was observed in all three epiphyses. A preliminary analysis showed that the asymmetric group of individuals in the study sample includes all the rural-to-urban migrants, relative to the symmetric group. KEY WORDS skeletal age; rib maturation; Lisbon collection; fluctuating asymmetry

Mechanistic interpretations of bone cross-sectional shapes are based on the paradigm of shape optimization such that bone offers maximum mechanical resistance with a minimum of material. Recent in vivo strain studies (Demes et al., Am J Phys Anthropol 106 (1998) 87-100, Am J Phys Anthropol 116 (2001) 257-265; Lieberman et al., Am J Phys Anthropol 123 (2004) 156-171) have questioned these interpretations by demonstrating that long bones diaphyses are not necessarily bent in planes in which they offer maximum resistance to bending. Potential limitations of these in vivo studies have been pointed out by Ruff et al. (Am J Phys Anthropol 129 (2006) 484-498). It is demonstrated here that two loading scenarios, asymmetric bending and buckling, would indeed not lead to correct predictions of loads from strain. It is also shown that buckling is of limited relevance for many primate long bones. This challenges a widely held view that circular bone cross sections make loading directions unpredictable for bones which is based on a buckling load model. Asymmetric bending is a potentially confounding factor for bones with directional differences in principal area moments ([I.sub.max] > [I.sub.min]). Mathematical corrections are available and should be applied to determine the bending axis in such cases. It is concluded that loads can be reliably extra-polated from strains. More strain studies are needed to improve our understanding of the relationships between activities, bone loading regimes associated with them, and the cross-sectional geometry of bones. KEY WORDS cross-sectional geometry; asymmetric bending; buckling; second moment of area

For methodological or other reasons, a variety of skeletal elements are analyzed and subsequently used as a basis for describing general bone loss and mass. However, bone loss and mass may not be uniform within and among skeletal elements of the same individual because of biomechanical factors. We test the hypothesis that a homogeneity in bone mass exists among skeletal elements of the same individual. Measures indicative of bone mass were calculated from the midshafts of six skeletal elements from the same individuals (N = 41). The extent of intraskeletal variability in bone mass (relative cortical area) was then examined for the entire sample, according to age, sex, and pathological status. The results of the analysis showed that all measures reflect a heterogeneity in bone mass (P [less than or equal to] 0.001). Specifically, differences were observed between the bones of the upper limb and those of the lower limb. Both sexes showed intraskeletal variability in bone mass, but the difference between the sexes is not significant (P = 0.509). When the sample is subdivided according to age, all groups show intraskeletal variability in bone mass, but the difference did not differ significantly among the groups (P = 0.217). However, significant differences in intraskeletal variability are observed between individuals below and above the age of 50. Pathological individuals show intraskeletal variability in bone mass, but the difference between the pathological and non-pathological groups is not significant (P = 0.095). These results indicate that the bone mass of any particular skeletal element is intricately tethered to its specific mechanical loading environment. KEY WORDS mechanical loading; bone loss; aging; cortical bone; skeletal biology

Traditional measures of structural stiffness in the primate skeleton do not consider the heterogeneous material stiffness distribution of bone. This assumption of homogeneity introduces an unknown degree of error in estimating stiffness in skeletal elements. Measures of weighted stiffness can be developed by including heterogeneous grayscale variations evident in computed tomographic (CT) images. Since gray scale correlates with material stiffness, the distribution of bone quality and quantity can be simultaneously considered. We developed weighted measures of bending resistance and applied these to CT images at three locations along the mandibular corpus in the hominoids Gorilla, Pongo, and Pan. We calculated the traditional (unweighted) moment of inertia for comparison to our weighted measure, which weighs each pixel by its gray-scale value. This weighing results in assignment of reduced moment of inertia values to sections of reduced density. Our weighted and unweighted moments differ by up to 22%. These differences are not consistent among sections, however, such that they cannot be calculated by simple correction of unweighted moments. The effect of this result is that the rank ordering of individual sections within species changes if weighted moments are considered. These results suggest that the use of weighted moments may spur different interpretations of comparative data sets that rely on stiffness measures as estimates of biomechanical competence. KEY WORDS biomechanics; bone density; computed tomography; image analysis; moment of inertia

Multilevel modeling procedures were used to model longitudinal adolescent growth of the humerus, radius, femur, and tibia in boys and girls. Growth velocity variation is much higher among the girls and the tibia is the most variable of the four long bones.

This study uses measures of cross-sectional robusticity and asymmetry (based on humeral areal and inertial cross-sectional components) to test a prediction from bone remodeling theory that a physically active 18th century Quebec prisoner of war sample (N = 25) should have more robust and asymmetrical humeri than a nonphysically active 20th century New Mexico suburbanite sample (N = 27). Narrative accounts document that prisoners of war engaged in labor-intensive activities, and these activities were confirmed by observations of osteoarthritis and other pathologies. The suburbanite sample, for the most part, did not engage in such activities. The prisoners had higher levels of pathology than the suburbanites (e.g., 80% vs. 22% osteoarthritis; F - 17.95, P < 0.01). For robusticity, the populations did not differ significantly in total area, cortical area, moment areas of inertia about the mediolateral plane, or polar moment area of inertia. The Quebec prison sample did have significantly higher values for moment areas of inertia about the anteroposterior plane. For asymmetry, the populations did not differ in any values (total area, cortical area, moment areas of inertia about the mediolateral plane, moment areas of inertia about the anteroposterior plane, or polar moment of inertia). Thus, examinations of cross-sectional robusticity and asymmetry failed to conclusively confirm the hypothesis that intensive labor leads to changes in humeral morphology. Possible explanations for the lack of differences are discussed, such as poor diet impeding bone remodeling. Nevertheless, the one significant finding suggests that cross-sectional shape is more useful in reconstructing activity patterns than amount of bone in a cross section. Results from this study join those from other recent investigations to suggest that additional controls are required before cross-sectional differences may be confidently attributed to activity patterns. Am J Phys Anthropol 126:311-317, 2005. KEY WORDS cross-sectional morphology; humeri; robusticity; asymmetry

In a good state of preservation, bone conserves the entire protein pattern of extracellular bone matrix proteins over thousands of years. The quality of the profiles of matrix proteins isolated from ancient bones (ranging from the pre-Pottery Neolithic Phase to Early Modern Times from different archaeological sites in different geographical areas), separated by electrophoresis, is as good as those from recent bones. Molecules arising from collagenous proteins (e.g., collagen type I), from the noncollagenous group (e.g., osteonectin), and from the immune system (e.g., immunoglobulin G) were identified in Western blots by specific antibodies. A comparative study of the immunoglobulin G content of the bones of five prehistoric children showed the lowest immunoglobulin G content in a child who suffered from chronic scurvy. Ancient bone proteins were also separated by two-dimensional electrophoresis. This technique makes fractionation of the complex protein mixtures of extracellular bone matrix more reproducible. Bone retains a chemical memory of earlier metabolic stimuli in its configuration of collagenous and noncollagenous proteins. In combination with the results of the microscopic examination of ancient bone, it should be possible to obtain more reliable information on the history and the evolution of diseases, based on analysis of intact proteins. KEY WORDS intact ancient bone-matrix proteins; Western blot; 2-D electrophoresis; proteome analysis

Local variation in cortical bone thickness in the postcanine mandibular corpus appears to be stereotypical among anthropoids. Specifically, at sections under the molars, lingually situated cortical bone is typically thinner than that along the lateral aspect. This pattern applies despite phylogenetic, dietary, and allometric differences among the anthropoids sampled to date. Demes et al. (Food Acquisition and Processing in Primates [1984] New York: Plenum Press, p. 369-390) employed a theoretical analysis of mastication in Gorilla and Homo to argue that this pattern could be explained with reference to biomechanical stresses. Specifically, they proposed that the combined effects of torsion and direct shear on the working-side corpus create a condition in which net stresses and strains are reduced along the lingual cortical plate. Demonstration of this effect would suggest a functional linkage between localized differences in bone mass and strain gradients in the facial skeleton. We conducted an empirical evaluation of the effects of the combined loads of torsion and direct shear in vitro on a sample of formalin-fixed human mandibles. Rosette strain gages were affixed to the lateral and medial aspects of the corpus in each specimen, and surface strains were recorded separately under controlled torsional and occlusal loads, and under simultaneous application of these loads. The hypothesis that lingual strains are reduced under combined twisting and occlusal loads was generally supported; however, we observed reduction in surface strains at some sites along the lateral aspect of the corpus under these combined loads as well. These unexpected findings are attributable to unanticipated loading conditions imposed by occlusal forces, which result from sources of stress in addition to direct shear. These experiments provide provisional support for the hypothesis that superposed sources of bone strain produce large strain gradients between buccal and lingual aspects of the mandibular corpus, and that local variation in bone mass may be associated with these gradients. KEY WORDS mastication; biomechanics; skull; primates; torsion

At the microstructural level, bones remodel throughout life. This process is recorded in bone cortex as osteons. A.more comprehensive understanding of the interaction between genetic regulation and environmental factors in osteon remodeling will increase the value of this skeletal record and enable more accurate reconstruction of individual life histories. The purpose of this study was to examine the contribution of maternal lineage to normal age and sex variation in osteon remodeling dynamics in Macaca mulatta. Femoral cross sections from 57 Cayo Santiago-derived rhesus macaques representing five matrilines were examined to evaluate the effect of genetic relatedness on osteon remodeling dynamics. Analysis of variance revealed an effect of maternal lineage on osteon area and Haversian canal area. The other variables did not differ significantly among matrilines. Analysis of covariance revealed no significant interactions among age, sex, and matriline for any of the microstructural variables. KEY WORDS histomorphometry; skeletal genetics; bone remodeling; rhesus macaque; cortical bone

Material properties and their variations in individual bone organs are important for understanding bone adaptation and quality at a tissue level, and are essential for accurate mechanical models. Yet material property variations have received little systematic study. Like all other material property studies in individual bone organs, studies of the human mandible are limited by a low number of both specimens and sampled regions. The aims of this study were to determine: 1) regional variability in mandibular material properties, 2) the effect of this variability on the modeling of mandibular function, and 3) the relationship of this variability to mandibular structure and function. We removed 31 samples on both facial and lingual cortices of 10 fresh adult dentate mandibles, measured cortical thickness and density, determined the directions of maximum stiffness with a pulse transmission ultrasonic technique, and calculated elastic properties from measured ultrasonic velocities. Results showed that each of these elastic properties in the dentate human mandible demonstrates unique regional variation. The direction of maximum stiffness was near parallel to the occlusal plane within the corpus. On the facial ramus, the direction of maximum stiffness was more vertically oriented. Several sites in the mandible did not show a consistent direction of maximum stiffness among specimens, although all specimens exhibited significant orthotropy. Mandibular cortical thickness varied significantly (P < 0.001) between sites, and decreased from 3.7 mm (SD = 0.9) anteriorly to 1.4 mm posteriorly (SD = 0.1). The cortical plate was also significantly thicker (P < 0.003) on the facial side than on the lingual side. Bone was 50-100% stiffer in the longitudinal direction ([E.sub.3], 20-30 GPa) than in the circumferential or tangential directions ([E.sub.2] or [E.sub.1]; P < 0.001). The results suggest that material properties and directional variations have an important impact on mandibular mechanics. The accuracy of stresses calculated from strains and average material properties varies regionally, depending on variations in the direction of maximum stiffness and anisotropy. Stresses in some parts of the mandible can be more accurately calculated than in other regions. Limited evidence suggests that the orientations and anisotropies of cortical elastic properties correspond with features of cortical bone microstructure, although the relationship with functional stresses and strains is not clear. KEY WORDS ultrasound; bone; biomechanics; development; function

We report on new standards for estimating long bone length from incomplete bones for use in forensic and archaeological contexts in Central America. The measurements we use closely follow those defined by Steele ([1970] Personal Identification in Mass Disasters; Washington, DC: Smithsonian Institution), but we add several new landmarks. We measured the femur, humerus, tibia, and fibula of 100 Maya skeletons (68 males, 32 females) recovered from forensic exhumations. We derived the equations by regressing bone segment length on bone length, and solved for bone length to maximize, the utility of the equations for taller populations. We generated equations for all segments that were significantly correlated with bone length for males, for females, and for both sexes combined, but accepted only regressions with [r.sup.2] > 0.85 as reliable. Landmarks defined by muscle attachment sites were more variable in location than landmarks on articular architecture; thus we retained few equations that use these landmarks. We tested the male and combined sex equations on 36 males of unknown ethnicity exhumed from a military base in Guatemala, and found that the equations performed satisfactorily. We also evaluated the performance of equations by Steele ([1970] Personal Identification in Mass Disasters; Washington, DC: Smithsonian Institution) and Jacobs ([1992] Am J Phys Anthropol 89:333-345) on the Maya bones, and conclude that significant population variation in long bone proportions hinders their application in Central America. KEY WORDS forensic anthropology; stature; long bone fragments; regression; Maya

Body mass estimation equations are generated from long bone cross-sectional diaphyseal and articular surface dimensions in 176 individuals and 12 species of hominoids and cercopithecoids. A series of comparisons is carried out to determine the best body mass predictors for each of several taxonomic/locomotor groupings. Articular breadths are better predictors than articular surface areas, while cross-sectional shaft strengths are better predictors than shaft external breadths. Percent standard errors of estimate (%SEEs) and percent prediction errors for most of the better predictors range between 10-20%. Confidence intervals of equations using sex/species means are fairly representative of those calculated using individual data, except for sex/species means equations with very low %SEEs (under about 10%), where confidence intervals (CIs) based on individuals are likely to be larger. Given individual variability, or biological 'error,' this may represent a lower limit of precision in estimating individual body masses. In general, it is much more preferable to determine at least broad locomotor affinities, and thus appropriate modern reference groups, before applying body mass estimation equations. However, some structural dimensions are less sensitive to locomotor distinctions than others; for example, proximal tibial articular M-L breadth is apparently 'locomotor blind' regarding body mass estimation within the present study sample. In other cases where locomotor affiliation is uncertain, mean estimates from different reference groups can be used, while for some dimensions no estimation should be attempted. The techniques are illustrated by estimating the body masses of four fossil anthropoid specimens of Proconsul nyanzae, Proconsul heseloni, Morotopithecus bishopi, and Theropithecus oswaldi. Am J Phys Anthropol 120:16-37, 2003. KEY WORDS skeleton; postcranial; hominoid; cercopithecoid; body weight

Light microscopy, particularly the use of polarized light, has such a high value for the differential diagnosis of dry bones that it can no longer be neglected. Alterations caused intra vitam by disease or other living conditions can clearly be differentiated by this technique from changes due to postmortem reactions (e.g., pseudopathology). As a reliable diagnosis is the basis not only of the study of case reports but also of the etiology and epidemiology of diseases in ancient populations, paleopathologists would be well-advised to employ histological analysis for their research, to avoid false diagnoses. The necessary basis for such research is the knowledge of the general histology, histogenesis, and growth as well as pathophysiology of bone. Some new techniques which facilitate the practical use of microscopic analysis, such as the preparation of thin-ground sections from undecalcified bone samples and nonrehydrated mummified soft tissues, are described. Selected examples of mechanisms of pathological bone changes, particularly the determination of vestiges of diseases in macerated bones by microscopy, are presented. Emphasis is placed on the differential diagnoses of proliferative reactions (e.g., periosteal processes of long bones and the skull). In this context, the importance of meningeal reactions on the endocranial lamina of the skull for morbidity and mortality in ancient populations is demonstrated. Furthermore, porotic hyperostosis of the skull vault and the orbital roof, i.e., the cribra cranii externa and cribra orbitalia, is discussed. Selected examples of the etiology and epidemiology of ancient diseases are presented (e.g., anemia, scurvy, rickets, and meningeal diseases), and ideas on living conditions and their implications for the origin and the spread of disease are given to establish a better understanding of deficiency and infectious diseases in the past. Yrbk Phys Anthropol 44: 106-147, 2001. KEY WORDS paleopathology; microscopy; etiology; epidemiology; inflammatory diseases; porotic hyperostosis

This article uses a cybernetic approach to examine factors contributing to bone health and common bone disorders. A paradigm that incorporates information on the mechanisms, signals, and dynamic systems involved in bone physiology provide new insight into causes of osteoporosis and factors related to whole-bone strength.

The os intermetatarseum is a relatively common accessory bone of the human foot located at the tarsometatarsal border between the first and second metatarsals. It can occur as an independent ossicle or as an osseous spur projecting from the proximal ends of the first two metatarsals, or the distal end of the first cuneiform. To determine the frequency of this congenital defect in native North American groups and East Asians from Japan, the skeletons of 846 Native Americans and 125 modern Japanese and Ainu were examined for the presence of the os intermetatarseum. The North American skeletons are from archaeological sites in various parts of Canada and the United States, including the Arctic coast, the Subarctic, the Aleutian Islands, the Northern Plains, the Illinois River area, and the Southwest. Overall frequencies ranged from no occurrence among the Arctic samples to 8% of individuals from Pecos Pueblo. Second metatarsal spurs occurred in particularly high frequencies among American Indians, whereas the East Asians were only found to have os intermetatarseums associated with the first cuneiform. Because pedigrees have shown the os intermetatarseum to be an inherited defect, its high frequency among some Native Americans may be due, in part, to a higher degree of genetic relatedness among the individuals in the North American samples than among the relatively modern East Asians. KEY WORDS paleopathology; accessory bone; foot defect; inherited condition

The possibility of smaller osteons in the cortical bone of Late Pleistocene human populations begs the question of how these histological features vary within individual skeletons among and between populations. The distributional characteristics of total osteon area (On.Ar) and Haversian canal area (H.Ar) are explored using data from three samples of historically known individuals: ribs and femora from eighteenth-century Huguenots in England (Spiralfields, n = 20), ribs and femora from nineteenth-century British settlers in Canada (St. Thomas, n = 21), and ribs from twentieth-century South African cadavers (University of Cape Town; following curatorial classifications, n = 10 white, 10 black, 10 colored). Neither histological variable is normally distributed. About 96% of the random variation is within the individual bone sample. There are no significant differences between sexes for either variable in any sample, and age has no effect in most instances. Femoral osteons are significantly larger than rib osteons within individuals and across samples. Haversian canal area is more variable than On.Ar, especially in the twentieth-century sample, where within-sample coefficients of variation are frequently >100%. Using modern centiles developed here, some Late Pleistocene long bone samples have On.Ar values below the range of modern variation. Because of ribs' smaller cross-sectional areas and less broadly ranging values for On. At, ribs would provide a preferable site for future comparative studies. KEY WORDS histomorphometry; histology; cortical bone; Haversian canal; rib; femur; human variability

We measured whole body bone, fat and lean mass, by dual-energy x-ray absorptiometry, of third-grade children in a suburban public school district adjacent to Detroit. Of 1,340 eligible children, 773 participated. Using U.S. Census categories, parents identified their children as black/African-American (57%), white (38%), or one of several other categories (5%). Some of the participants also identified with a relatively large Middle Eastern subgroup (Chaldeans). Of the 773 participants, 734 are included in this report (71 Chaldeans, 226 whites, and 437 black/African-Americans; other categories are omitted). We describe body size, body composition, and physical activity levels in the three groups. The Chaldean and black children have significantly higher average whole body bone mineral content (BMC) than whites (P > 0.05), but are not different from each other. Lean mass and height are significantly greater for Chaldeans and blacks than for whites. The ratio of BMC to height was also significantly greater in Chaldeans and blacks compared with whites. Chaldeans have a significantly higher weight and fat mass than either the black or white children, and report significantly less physical activity than either the white or the black children. The higher bone mass among the Chaldean children may be partially explained by their greater body mass, but there is no readily apparent explanation for the observed ethnic differences in body size. We cannot exclude genetic or environmental factors not evaluated in this observational study. Our unexpected finding that Chaldean children, when analyzed as a separate group, are more similar in body composition to black/African-American than to white children contributes to a growing body of literature indicating that the uncritical use of 'race' categories may obscure rather than facilitate the identification of population differences. KEY WORDS body composition; absorptiometry; ethnicity; Middle Eastern

Transverse lines were examined in 633 long bones from 73 individuals exhumed from two burial sites in the Republic of Ireland: Waterford City and Tintern Abbey. The burials cover four distinct periods between the 11th and 17th centuries. Lines were most numerous in the tibia, especially in the distal segment, and were not seen in the humerus nor the proximal part of the femur. The number of lines varied between the proximal and distal segments of each long bone, and though apparently equal in number across the midline, there were significant differences in the incidence of lines between corresponding pairs of bones. Thus, it is unwise to rely on the results of a single bone or one type of long bone alone either to indicate the health status of an individual, or as the basis for assessing the health status of a small population. Such results should be used only in association with other indicators. KEY WORDS Transverse (Harris) lines, Irish archaeology, Long bones

Little attention has been devoted to assessing the reproducibility of (paleo)pathological observations. Harris lines (HL) are among the markers most used to determine chronology of stresses suffered during growth. Nevertheless, their scoring entails remarkable methodological difficulty. Bone sections (S) and radiographs (R) of 29 adult tibiae of archeological provenance (medieval) were scored for HL by five observers. At regular intervals of time, each observer gave two independent counts on both series. Results show a) a substantial inter-observer disagreement of HL estimates for both sectional and radiographic records, and b) a high level of intraobserver error.

It has been demonstrated in clinical and experimental studies that subarticular trabecular bone responds to mechanical loads transmitted across joints through changes in mass and structural organization. We investigated differences in mass, volume, and density of subarticular trabecular bone of the humeral and femoral head in Hylobates syndactylus, Colobus guereza, and Papio cynocephalus. Our hypothesis was that variations in trabecular properties between taxa may reflect differences in mechanical loading associated with different locomotor repertoires. A nondestructive method for measuring trabecular properties using optical luminance data measured from radiographs was developed. We also examined the relationship between internal trabecular properties and the external size and surface area of the humeral and femoral heads in these taxa. Our results suggest that internal and external articular structure are relatively independent of each other and may be adapted to different aspects of the mechanical environment. Differences in trabecular mass between taxa appear to correspond to differences in the magnitudes of mechanical loads borne by the joint, whereas articular volume and surface area are related primarily to differences in joint mobility. Because of the apparent physiological 'de-coupling' of articular mass and volume, variations in articular density (mass/volume) are difficult to interpret in isolation. Comparisons of internal and external articular structure may provide new ways to reconstruct the locomotor/positional behavior of extinct taxa.

A study was conducted to determine the relationship between bone mineral density (BMD) and blood pressure in 214 men, between 20-26 years of age. Although results showed diastolic blood pressure negatively related to femoral neck BMD, further studies would be required to determine the causal relation between elevated blood pressure and low bone mass.

Computer tomography offers a noninvasive possibility to examine cross-sectional geometry of long bones. We tested different methods (Nagurka and Hayes 1980, Corcacon et. al. 1995) for calculating biomechanical parameters from CT images of long bone cross section based on trigonometric and image analysis approaches using archaeologic (75 adult bronze age individuals from 3 different populations from Lower Austria) and recent samples (anatomical collection from the Institute of Anatomy, University of Vienna) of long bones. Both approaches do not only lead to different problems concerning computation but also to different biological meanings of the calculated biomechanical parameters. However, image analysis of digital CT-images suggests an easier and observer independent way of calculating the desired biomechanical parameters automatically and directly from standard medical image-files (DICOM). We have developed computer software that allows optional, interactive and automated data preparation for computation, depending on the state of preservation of the bone samples and the method applied. Our software uses the CT files directly and offers immediate computation of biomechanical parameters with either approach and as a series of anatomical context. Therefore it is possible to analyse larger series of long bones in a convenient period of time. After computation the results can be easily exported to other programs for further calculations like statistical analysis and 3D visualisation. Because of the modular design of the computer program new data processing units can be added in future.

Controlled diet experiments and observations on wild East African mammals, show a clear influence of trophic level on bone apatite oxygen isotope ratios. Twenty litters of rats were raised from weaning age on seven kinds of controlled diets, each with 5%, 20% and 70% protein. Water oxygen isotope composition was constant. Oxygen isotope ratios of bone apatite carbonate decreased on average by 2.5% between 5% and 20% protein and 1% between 20 and 70% protein diets. Oxygen isotope ratios of bone of five litters raised under several configurations of heat and water stress on 20% and 70% protein diets did not differ significantly from those of non-stressed controls. The oxygen isotopic composition of mammal bone and tooth apatite phosphate and carbonate was also determined for 81 individuals of 21 species collected in the central Rift Valley of Kenya, along an altitude transect from lake margin riparian woodland and savanna grassland to montane forest. There is substantial intra- and inter-specific variation in bone phosphate and carbonate [delta][sup.18]O within and between habitats. Lower [delta][sup.18]O values are found at high altitudes. Arboreal folivores (tree hyrax and colobus) in montane forest have the highest values. Carnivores and omnivores have the lowest values in all habitats. High protein diets appear to be associated with low [delta][sup.18]O values on both experimental and natural diets. These data suggest the potential of oxygen isotope ratios of bone for identifying carnivory in fossil mammal communities. Supported by National Science Foundation (USA) grants BNS9010937 and SBR9212466.