Functional and morphological correlates of mandibular symphyseal form in a living human sample
Article first published online: 22 NOV 2013
Copyright © 2013 Wiley Periodicals, Inc.
American Journal of Physical Anthropology
Volume 153, Issue 3, pages 387–396, March 2014
How to Cite
Holton, N. E., Franciscus, R. G., Ravosa, M. J. and Southard, T. E. (2014), Functional and morphological correlates of mandibular symphyseal form in a living human sample. Am. J. Phys. Anthropol., 153: 387–396. doi: 10.1002/ajpa.22437
- Issue published online: 12 FEB 2014
- Article first published online: 22 NOV 2013
- Manuscript Revised: 8 NOV 2013
- Manuscript Accepted: 8 NOV 2013
- Manuscript Received: 24 JAN 2013
- National Science Foundation . Grant Number: BCS-0550036
- cortical bone;
- developmental plasticity;
Variation in recent human mandibular form is often thought to reflect differences in masticatory behavior associated with variation in food preparation and subsistence strategies. Nevertheless, while mandibular variation in some human comparisons appear to reflect differences in functional loading, other comparisons indicate that this relationship is not universal. This suggests that morphological variation in the mandible is influenced by other factors that may obscure the effects of loading on mandibular form. It is likely that highly strained mandibular regions, including the corpus, are influenced by well-established patterns of lower facial skeletal integration. As such, it is unclear to what degree mandibular form reflects localized stresses incurred during mastication vs. a larger set of correlated features that may influence bone distribution patterns. In this study, we examine the relationship between mandibular symphyseal bone distribution (i.e., second moments of area, cortical bone area) and masticatory force production (i.e., in vivo maximal bite force magnitude and estimated symphyseal bending forces) along with lower facial shape variation in a sample of n = 20 living human male subjects. Our results indicate that while some aspects of symphyseal form (e.g., wishboning resistance) are significantly correlated with estimates of symphyseal bending force magnitude, others (i.e., vertical bending resistance) are more closely tied to variation in lower facial shape. This suggests that while the symphysis reflects variation in some variables related to functional loading, the complex and multifactorial influences on symphyseal form underscores the importance of exercising caution when inferring function from the mandible especially in narrow taxonomic comparisons. Am J Phys Anthropol 153:387–396, 2014. © 2013 Wiley Periodicals, Inc.