The 82nd Annual Meeting of the American Association of Physical Anthropologists (2013)

Ecogeographic patterning in maxillary sinus form among modern humans


Department of Anthropology, Texas A&M University

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While patterns of modern human craniofacial diversity are widely documented for external structures, considerably less is known about internal morphology. Maxillary sinus (MS) form is often thought to vary as a function of the nasal cavity (NC), whose size and shape is climatically driven. However, preliminary studies have provided conflicting results, likely due to geographically-limited samples and a focus on MS volume. This study addresses these issues by evaluating ecogeographic patterns of various MS dimensions in a large sample of modern humans (n=202) spanning 11 climatically-diverse regions. All MS dimensions, except length, were significantly correlated with latitude. Although most MS dimensions were inversely correlated with NC distances, the MS surface-area-to-volume ratio exhibited a positive allometric relationship with NC breadth among groups. While differences in allometric slopes were evident between populations, a MANOVA failed to find significant differences in MS dimensions among the 11 samples. However, when grouped by broad climatically-based categories, t-tests indicated that hot-adapted individuals had significantly longer, narrower, lower, and less-volumetric sinuses compared to cold-adapted individuals. Hot-adapted individuals also had higher-surface-area-to-volume ratios, indicating more cylindrically-shaped sinuses. Overall, these results suggest that while differences in MS form are only evident among broad climatically-based categories, significant differences in the relative relationships between the MS and NC are apparent among more precise geographic regions. Following previous studies, these results highlight the importance of examining the interaction between the MS and NC to understand how these structures vary among modern humans in relation to diverse environments.

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