Examining Activity Patterns and Biological Confounding Factors: Differences between Fibrocartilaginous and Fibrous Musculoskeletal Stress Markers

Abstract

The present study examines a sample of 105 hunter–gatherer California Amerinds to determine whether fibrocartilaginous musculoskeletal stress markers (MSMs) are better for activity reconstructions than fibrous MSMs. Femoral and humeral head diameters were measured as proxies to body size. All data were analysed for statistical significance using non-parametric tests. Fibrous MSMs of the left deltoideus, left and right hip adductors, and left and right tibial soleus correlate positively with body size proxies. For fibrocartilaginous MSMs, the right humeral teres minor insertion negatively correlates with humeral head diameter. Both types of MSMs correlate positively with age. More upper limb fibrocartilaginous MSMs display asymmetry than do upper limb fibrous MSMs. Lower limb sex differences were found at the same MSM sites that correlated with body size. Upper limb sex differences at the right teres major, a fibrous site, and the right triceps brachii, a fibrocartilaginous site, seem to reflect activity patterns. Results suggest that fibrocartilaginous MSMs are more useful in reconstructing activity patterns because they display more asymmetry in upper limbs and are less affected by body size than are fibrous MSMs. Yet, correlations with age and a lack of variability at fibrocartilaginous MSM sites may hinder their utility in activity reconstructions. Copyright © 2012 John Wiley & Sons, Ltd.