Publications [#50228] of Todd R. Yokley

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1. Yokley, T.R. "Ecogeographic variation in human nasal passages." (2006). Paper presented at the 75th Annual Meeting of the American Association of Physical Anthropologists, March 10, 2006, Anchorage, AK (Abstract: Am. J. Phys. Anthropol. Suppl. 42, 191).
   (last updated on 2006/11/09)

   Abstract:
   Nearly a century’s worth of research into ecogeographic variation in external nasal morphology has shown that individuals from cold and/or dry climates tend to have tall, narrow noses, while individuals from hot and humid climates tend to have noses that are short and broad. This pattern of variation in external nasal anatomy is thought to be related to the amount of internal mucosal surface area relative to the volume of air within the nasal passages, but no one has explicitly demonstrated this relationship. Individuals whose ancestors evolved in colder, drier climates should possess higher surface-area-to-volume (SA/V) ratios than individuals whose ancestors evolved in warmer, more humid climates. A high SA/V ratio allows relatively more air to come in contact with the mucosa, thereby facilitating more efficient heat and moisture exchange, whereas a low SA/V ratio allows for better heat dissipation. To test this hypothesis, mucosal surface areas and nasal passage volumes were collected from a sample of CT scans of patients of European and African ancestry from the University of North Carolina Hospital as well as a sample of native South Africans from Johannesburg Hospital. Skeletal dimensions of the nasal aperture and nasal cavity were also measured to determine if they co-vary with SA/V. Results of this analysis indicate that individuals of European descent possess significantly higher SA/V ratios than both native Africans and individuals of African descent and that nasal aperture dimensions are correlated with SA/V, although not as highly as dimensions of the nasal cavity.