Enthesopathy Formation in the Humerus: Data from Known Age-at-Death and Known Occupation Skeletal Collections

Centre for Research in Anthropology, 1600-083 Lisbon, Portugal.
American Journal of Physical Anthropology (Impact Factor: 2.38). 01/2009; 141(4):550-60. DOI: 10.1002/ajpa.21171
Source: PubMed


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. Fisher's 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.

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    • "Rabey et al. / Journal of Human Evolution xxx (2014) 1e12 7 Please cite this article in press as: Rabey, K.N., et al., Locomotor activity influences muscle architecture and bone growth but not muscle attachment site morphology, Journal of Human Evolution (2014), Hawkey and Merbs, 1995; Montgomery et al., 2005; Cardoso and Henderson, 2010; Jurmain et al., 2012; Niinim€ aki et al., 2013). Indeed, elevated activity influenced differential periosteal growth in the humerus and throughout the deltoid crest (Table 1; Figs. 4 and 6). "
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    ABSTRACT: The ability to make behavioural inferences from skeletal remains is critical to understanding the lifestyles and activities of past human populations and extinct animals. Muscle attachment site (enthesis) morphology has long been assumed to reflect muscle strength and activity during life, but little experimental evidence exists to directly link activity patterns with muscle development and the morphology of their attachments to the skeleton. We used a mouse model to experimentally test how the level and type of activity influences forelimb muscle architecture of spinodeltoideus, acromiodeltoideus, and superficial pectoralis, bone growth rate and gross morphology of their insertion sites. Over an 11-week period, we collected data on activity levels in one control group and two experimental activity groups (running, climbing) of female wild-type mice. Our results show that both activity type and level increased bone growth rates influenced muscle architecture, including differences in potential muscular excursion (fibre length) and potential force production (physiological cross-sectional area). However, despite significant influences on muscle architecture and bone development, activity had no observable effect on enthesis morphology. These results suggest that the gross morphology of entheses is less reliable than internal bone structure for making inferences about an individual's past behaviour.
    Journal of Human Evolution 11/2014; 78. DOI:10.1016/j.jhevol.2014.10.010 · 3.73 Impact Factor
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    • "Note that these methods, unlike others [32],[95] do not take into account the type of enthesis (i.e. fibrous vs. fibrocartilaginous), a factor often considered in studies on EC [2],[20]–[22],[96]. Nonetheless, it was chosen for: (a) the previous experience of the author with this method [19],[36],[97],[98]; (b) the site-specificity of the method for scoring robusticity (therefore indirectly taking into account the anatomy of each enthesis), and (c) the chance to consider separately different variables (robusticity and enthesopathies). "
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    ABSTRACT: Entheseal changes have been widely studied with regard to their correlation to biomechanical stress and their usefulness for biocultural reconstructions. However, anthropological and medical studies have demonstrated the marked influence of both age and sex on the development of these features. Studies of entheseal changes are mostly aimed in testing functional hypotheses and are mostly focused on modern humans, with few data available for non-human primates. The lack of comparative studies on the effect of age and sex on entheseal changes represent a gap in our understanding of the evolutionary basis of both development and degeneration of the human musculoskeletal system. The aim of the present work is to compare age trajectories and patterns of sexual dimorphism in entheseal changes between modern humans and African great apes. To this end we analyzed 23 postcranial entheses in a human contemporary identified skeletal collection (N = 484) and compared the results with those obtained from the analysis of Pan (N = 50) and Gorilla (N = 47) skeletal specimens. Results highlight taxon-specific age trajectories possibly linked to differences in life history schedules and phyletic relationships. Robusticity trajectories separate Pan and modern humans from Gorilla, whereas enthesopathic patterns are unique in modern humans and possibly linked to their extended potential lifespan. Comparisons between sexes evidence a decreasing dimorphism in robusticity from Gorilla, to modern humans to Pan, which is likely linked to the role played by size, lifespan and physical activity on robusticity development. The present study confirms previous hypotheses on the possible relevance of EC in the study of life history, pointing moreover to their usefulness in evolutionary studies.
    PLoS ONE 09/2014; 9(9). DOI:10.1371/journal.pone.0107963 · 3.23 Impact Factor
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    • "MSM scores (for scoring methods see e.g. Hawkey & Merbs 1995; Weiss 2003) are positively correlated with age and body size and higher in average in males than in females, due to greater muscle volume in the former; their variance due to differences in labour intensity is less than these three covariates (Weiss 2003, 2004, 2007; Cardoso & Henderson 2010; Niinimäki 2011). Moreover, loading intensity seems to be more important than loading frequency or duration (Churchill & Morris 1998). "
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    ABSTRACT: Recently, a report on two human skeletons from an Early Bronze Age tomb excavated at Tell Ashara, Syria has been published in International Journal of Osteoarchaeology. One individual was identified as a warrior following these criteria: (i) size and robustness of bones, (ii) cut marks on the humerus, (iii) reduction of the ulnar styloid process, both interpreted as healed weapon-related trauma, (iv) well-developed muscle insertions, and (v) degenerative joint disease. Actually, none of these five criteria support the conclusion because of the following reasons: (i) not necessarily all tall and robust men become warriors, (ii) the post mortem origin of cut marks on the humerus is more likely than sharp force trauma, (iii) there are several possible causes of the unusual ulnar styloid shape other than weapon-related trauma, (iv) the interpretation of musculoskeletal stress markers and (v) degenerative joint disease lacked control for age, sex and body size. Copyright © 2012 John Wiley & Sons, Ltd.
    International Journal of Osteoarchaeology 09/2014; 24(5). DOI:10.1002/oa.2243 · 0.95 Impact Factor
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