Charlotte Henderson

Enthesopathy formation in the humerus: Data from known age‐at‐death and known occupation skeletal collections

Enthesopathies, in the guise of musculoskeletal skeletal stress markers (MSM), have been widely used to reconstruct activity levels in human skeletal populations. In general, studies have focused on their presence in the upper limb, which is used in the majority of daily activities. The aim of this study was to use some of the attachment sites on the humerus to explore the relationship between enthesopathy formation, activity, and the ageing process. The skeletal sample used in this study comprised male adult skeletons with known age-at-death and known occupations from the late-19th and early-20th century cemeteries in Portugal. The enthesopathies were recorded as either present or absent. Statistical analysis using Fishers exact tests and logistic regression was undertaken to determine whether associations could be found between specific activities or socioeconomic status (manual or nonmanual workers), and age and enthesopathy presence. Left and right sides were analyzed separately. Fishers exact tests were used to determine the relationship between activity and enthesopathy, and they demonstrated no association between activity and enthesopathies (P > 0.01). The results of the logistic regression established that age was the single most significant factor in enthesopathy formation (P > 0.05). This study found that, in these samples, age-at-death, and therefore age-related degeneration rather than degeneration caused by activities, was the primary cause of enthesopathy formation. Considering the difficulties of reliably ageing adult human skeletal remains, this is a major issue for studies of activity using enthesopathies.

Subsistence strategy changes: The evidence of entheseal changes

Changes in subsistence strategy have caused some of the profoundest changes to the structure and health of humans. This study aims to test whether these changes have reduced work-load as assessed by entheseal changes. Entheseal changes, formerly called musculoskeletal stress markers, are thought to reflect muscle usage throughout life, although it is widely agreed that they have a multifactorial origin. This paper uses a meta-analysis of comparable published data to plot trends in time by muscle, enthesis type and sex. The results show that agriculturalists have the lowest scores for entheseal changes, with hunte-gatherers next highest and those working in industry the highest. These findings are the same for males and females, for most muscles and muscle groups. However, entheseal changes are highly correlated with increased age and the age distributions of the samples analysed could not be compared. It is, therefore, possible that differences in age distribution of the samples are one of the reasons for this finding. Recommendations are provided to reduce this and other limitations for future meta-analyses.

In search of consensus: Terminology for entheseal changes (EC)

This article presents a consensus terminology for entheseal changes that was developed in English by an international team of scholars and then translated into French, Italian, Portuguese, Spanish and German. Use of a standard, neutral terminology to describe entheseal morphology will reduce misunderstandings between researchers, improve the reliability of comparisons between studies, and eliminate unwarranted etiological assumptions inherent in some of the descriptive terms presently used in the literature.

Accounting for multiple effects and the problem of small sample sizes in osteology: a case study focussing on entheseal changes

Osteoarchaeological studies provide valuable information concerning living conditions and life course changes in past societies. However, many skeletal markers, such as entheseal changes, are multifactorial in aetiology; thus, their interpretation is not straightforward. Generalised linear models (GLMs) are ideal for analysing such phenomena, i.e. those with multiple underlying causative factors, but, to date, their use has been limited. This paper focuses attention on using these models to test hypotheses regarding the aetiology of entheseal changes, widely regarded as indicative of activity patterns, but which are also affected by ageing and body size. To demonstrate the use and limitations of these models, this paper provides an independent test of a previously developed GLM on an identified skeletal sample comprised of skeletons from four British sites (n = 58) which has a typical sample size for archaeological osteological analysis. In addition to this model, GLMs were developed to include the factor of body size and expand the models to test individual entheses, as well as joint complexes whereby multiple entheses for muscles which act synergistically have been pooled. The results indicate that the original model did not compare well with the frequencies of entheseal changes found in the British assemblage under study. The new models found no clear pattern of influence, although both ageing and body size were important for some entheses. GLMs are appropriate for testing the interaction of biological variables, but future studies need to take into account and test their applicability to archaeological sample sizes.

Do diseases cause entheseal changes at fibrous entheses

Fibrous entheses have been widely used to study activity-related stress to infer behavioural patterns in past populations. Unlike their fibrocartilaginous counterparts, the effect of disease processes has been less widely discussed in the osteoarchaeological literature. This study uses a literature review to ascertain whether specific pathological changes should be taken into account when recording fibrous entheses. Due to the anatomical structure of fibrous entheses it was hypothesised that diseases which affect the structure of bone or the periosteum might be a factor in causing entheseal changes. A search of over one hundred terms was performed in PubMed with no year range stipulated, but no papers were found which related to entheseal changes caused by any of the expected pathological processes. The paucity of literature might be due to lack of symptoms in living individuals, it is therefore suggested that a systematic study of skeletal remains is performed using recently developed recording methods to determine if pathological conditions need to be taken into account when recording entheseal changes to study activity-related stress. The search did highlight a link between calcific tendinitis and cortical erosion at fibrous entheses, and it is recommended that this is taken into account when interpreting entheseal changes in past populations.

The new Coimbra method for recording entheseal changes and the effect of age-at-death

Entheseal changes have been widely used in anthropology to study activity patterns, but there is an increasing awareness that ageing is associated with these changes. The aim of this study was to test each feature of the new Coimbra method for its variability, side asymmetry and its relationship with age. In addition to this, an overall relationship with age was tested for a larger sample. Males 16 and over from the Coimbra skeletal collection of historically identified individuals were recorded using the new method (N = 260). To reduce the impact of occupation, side variability in asymmetry and age were only tested in the labourers (N = 51). All occupation groups were included to test the overall relationship with age using a random forest test. The results show that scores lack variability for many of the features and entheses. Where there is side asymmetry this is typically in favour of higher scores in the right side, excepting the biceps brachii insertion. Most of the features scored show a relationship with ageing, but this is not uniform for all features or entheses. Some features are associated with an increase in age (bone formation and erosions), while others generally occur in younger individuals (fine porosity and textural change). Logistic regression showed that ageing explains at most 44% of the variability. This alongside the side asymmetry may indicate that biomechanics has an explanatory role.RésuméLes changements au niveau des enthèses ont été largement utilisés en anthropologie biologique pour discuter des patterns d’activités, malgré les études de plus en plus fréquentes associant ces changements principalement au vieillissement. L’objectif de cette étude est d’illustrer, pour chacune des modifications enregistrées avec la nouvelle méthode de Coimbra, la distribution générale des scores, l’asymétrie et leur relation à l’âge. Une étude plus globale sur l’effet du vieillissement a également été menée. L’analyse porte sur un échantillon de squelettes de sujets masculins décédés à 16 ans ou plus issus de la collection de squelettes identifiés de Coimbra (n = 260). Pour réduire l’influence de l’activité physique, seuls les sujets avec la profession de « trabalhador » (travailleur) ont été utilisés dans les tests sur l’asymétrie et l’âge (n = 51). Pour l’étude globale sur l’effet du vieillissement, toutes les professions ont été incluses dans une analyse utilisant les forêts aléatoires. Les résultats montrent que la variabilité des scores est faible pour la plupart des changements et des enthèses. Il existe une asymétrie assez claire avec des scores plus élevés du côté droit, sauf pour l’insertion du biceps brachii. La plupart des changements enregistrés présentent une corrélation positive avec l’âge au décès, sans toutefois être systématiques pour tous les changements ou toutes les enthèses considérées. Certains changements sont plus fréquents chez les sujets âgés (formation osseuse, érosion), alors que d’autres se retrouvent plus souvent chez les jeunes sujets (porosité fine et changement mineur de surface). Une régression logistique montre que le vieillissement explique au mieux 44 % de la variabilité perçue. Cela, ainsi que l’asymétrie directionnelle observée, pourrait indiquer que les phénomènes biomécaniques jouent un rôle dans l’apparition de ces changements.

Exploring poverty: skeletal biology and documentary evidence in 19th–20th century Portugal

Abstract Background: The inference of the state of wealth or poverty from human skeletal remains is a difficult task, as the limited number of skeletal changes are mediated by numerous other physiological, biomechanical and pathological events. In recent years, identified skeletal collections have become valuable resources in enabling aetiologies of these changes to be understood while controlling for some known causative factors, e.g. age, sex and occupation. This has favoured more rigorous data analysis and interpretation. Aim: This study compares the presence of osteological makers of occupation – specifically degenerative joint changes (DJC) – between socio-economically framed occupational groups whilst controlling for age-at-death. Materials and methods: A total of 603 individuals were distributed into seven occupational groups used as a proxy for their socio-economic status. Results: The results demonstrated that age was a contributing factor for DJC. Differences between occupational groups were only found for the hips, right shoulder and ankle. Conclusions: Differences found were not necessarily representative of low vs high socio-economic status. Furthermore, there are limitations associated with the use of occupation-at-death, based on documentary evidence, which does not necessarily reflect wealth-status.

Testing times: identifying puberty in an identified skeletal sample.

Abstract Background: Identifying the onset of puberty in skeletal remains can provide evidence of social changes associated with the onset of adulthood. Aim: This paper presents the first test of a skeletal method for identifying stages of development associated with the onset of puberty in a skeletal sample of known age and cause of death. Materials and methods: Skeletal methods for assessing skeletal development associated with changes associated with puberty were recorded in the identified skeletal collection in Coimbra, Portugal. Historical data on the onset of menarche in this country are used to test the method. Results: As expected, females mature faster than their male counterparts. There is some side asymmetry in development. Menarche was found to have been achieved by an average age of 15. Conclusions: Asymmetry must be taken into account when dealing with partially preserved skeletons. Age of menarche is consistent, although marginally higher, than the age expected based on historical data for this time and location. Skeletal development in males could not be tested against historical data, due to the lack of counterpart historical data. The ill health known to be present in this prematurely deceased population may have delayed skeletal development and the onset of puberty.

Is differential diagnosis attainable in disarticulated pathological bone remains? A case-study from a late 19th/early 20th century necropolis from Juncal (Porto de Mós, Portugal)

Differential diagnosis is a fundamental step in every palaeopathological study. It is a challenging exercise since many intrinsic and extrinsic factors may negatively impact the accurate interpretation of bone changes in human skeletal remains. Among these, the completeness and preservation of skeletal elements plays a significant role. This study aims to explore the limits of differential diagnosis in the analysis of disarticulated, fragmented bones. The sample consists of twelve adult bone fragments with noticeable changes. The remains were identified in a dis-articulated skeletal assemblage from the former necropolis of Juncal (Porto de Mós, Portugal), which probably closed in the late 19th century/early 20th century. They were analysed visually and with X-radiography, and the changes carefully described prior to differential diagnosis. Six bones presented signs of healed bone trauma and one showed features compatible with leg amputation. Periosteal reactions were observed in several bones, one of them resembling changes consistent with an overlying skin ulcer. Two bone fragments were identified as belonging to the same individual due to the matching bone changes. Despite the incomplete remains, a broader diagnosis was possible for most cases, which facilitated a discussion of health, medical and social care among the inhabitants of the region.