BIOMECHANICAL ANALYSIS OF MASTICATORY SYSTEM CONFIGURATION IN NEANDERTALS AND INUITS

Considerable debate has surrounded the adaptive significance of Neande rtal craniofacial morphology. Numerous unique morphological features o f this form have been interpreted as indicating an adaptation to inten se anterior tooth use. Conversely, it has been argued that certain fea tures related to muscle position imply a reduced mechanical advantage for producing bite forces on the incisors and canines. In this study, hypotheses about morphological specializations for anterior tooth use have been derived from a biomechanical model of Greaves (1978). These hypotheses were tested by performing separate pairwise comparisons of Neandertals and early Homo sapiens, and Inuits and Native Americans fr om Utah. Inuits are known to have produced repeated and high magnitude forces on their anterior dentition and therefore serve as a good mode l for a hominid adapted to intensive anterior tooth use. Biomechanical ly relevant dimensions of the masticatory system were measured using a computer-driven video analysis system and compared between the two ta xa in each comparison. The results of this study reveal a number of si milarities between the morphological specializations exhibited by Nean dertals and Inuits that can be related to intensified anterior tooth u se. The hypothesis that Neandertals were poorly designed for producing masticatory forces is rejected. Specializations that differ between t he two groups are interpreted as being the result of differential func tional demands placed on the postcanine dentition in Neandertals and I nuits. It is suggested that many of the unique morphological features of the Neandertal face are a response to intensified use of the anteri or dentition and the need to retain a sufficiently large postcanine oc clusal area necessary for a relatively high attrition diet.