Recent hominim cranial form and function

Godinho, Ricardo Miguel Alves Correia

Medicine
June 2016

Thesis or dissertation


Rights
© 2016 Ricardo Miguel Alves Correia Godinho. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder.
Abstract

This thesis aims to assess if biting mechanics drives craniofacial morphology in recent hominins. To that end, a virtual functional morphology toolkit, that includes Finite Element Analysis (FEA) and Geometric Morphometrics (GM), is used to simulate biting, measure bite force and quantify deformations arising due to simulated biting in Homo sapiens and its proposed ancestral species, Homo heidelbergensis. Moreover, the mechanical significance of the frontal sinus and of the brow-ridge is also assessed in Kabwe 1 (a Homo heidelbergensis specimen). The frontal sinus is examined by comparing the mechanical performance in three FE models with varying sinus morphology. A similar approach is applied to the brow-ridge study. This approach relies on the assumption that FEA approximates reality. Thus, a validation study compares the deformations experienced by a real cranium under experimental loading with those experienced by an FE model under equivalent virtual loading to verify this assumption. A sensitivity analysis examines how simplifications in segmentation impact on FEA results. Lastly, the virtual reconstruction of Kabwe 1 is described.

Results show that prediction of absolute strain magnitudes is not precise, but the distribution of regions of larger and smaller (i.e. pattern of) deformations experienced by the real cranium is reasonably approximated by FEA, despite discrepancies in the alveolus. Simplification of segmentation stiffens the model but has no impact on the pattern of deformations, with the exception of the alveolus. Comparison of the biting performance of Kabwe 1 and H. sapiens suggests that morphological differences between the two species are likely not driven by selection of the masticatory system. Frontal sinus morphogenesis and morphology are possibly impacted by biting mechanics in the sense that very low strains are experienced by this region. Because bone adapts to strains, the frontal sinus is possibly impacted by this mechanism. Lastly, biting mechanics has limited impact on brow-ridge morphology and does not explain fully the enormous brow-ridge of Kabwe 1. Hence, other explanations are necessary to explain this prominent feature.

Publisher
Hull York Medical School, The University of Hull and University of York
Sponsor (Organisation)
Fundação para a Ciência e a Tecnologia
Grant number
FCT; PhD funding reference: SFRH/BD/76375/2011
Qualification level
Doctoral
Qualification name
PhD
Language
English
Extent
7 MB
Identifier
hull:14365
QR Code