The role of soft tissues and minor osseous structures in cranial biomechanics

Sellés de Lucas, Victor

Engineering
November 2019

Thesis or dissertation


Rights
© 2019 Victor Sellés de Lucas. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder.
Abstract

Finite element analysis is now widely recognised as an invaluable technique to investigate and understand cranial biomechanics since it can incorporate the complexity of a skull’s geometry, its construction, different materials and complex loadings. However, while the biofidelity of some aspects of these models is increasing, most still only consider the larger bony structures of the skull. This study examines the role of soft tissues and some smaller bony parts, to determine whether they should also be incorporated in such studies of cranial biomechanics. The structures that have been investigated include: the dura mater, the falx cerebri and the tentorium cerebelli, the periodontal ligament, the nasal turbinates and the osseous nasal septum, the postorbital bars and septa and the bulk tissues that surround the cranial bones. They are considered both in terms of their functional role and as part of the general functioning of the FE model that includes them. For this purpose, two FE models were used: a model of a Felis silvestris catus, which was created specifically for this project, and an adaptation of a previous head model of Homo sapiens.

The results reveal that in Felis silvestris catus, the osseous tentorium does play a minor role in reducing stress in the parietal and temporal bones during feeding activities regarding of the biting regime. The causes of ossification and its possible mechanical role in several mammalian lineages, however, remain currently unclear. Moreover, inclusion of the nasal turbinates and the osseous part of the nasal septum is advisable in future FE models, as they impact the pattern of stress in the cranium, but the presence of generic bulk soft tissues in an FE model does not seem to have a meaningful effect on the results. On the other hand, modelling of the periodontal ligament has a localised effect in the alveolar region, but does not alter the general pattern of stress in the cranium.

In the Homo sapiens model, the postorbital bars and the postorbital septa not only help reduce strain in various areas of the cranium, but also shelter the contents of the orbit and avoid distortion of the eye. The postorbital septa also reduce strain in the postorbital bars and minimize asymmetrical deformation between the working and balancing sides in unilateral molar bites.

Altogether, this thesis offers a body of work which future researchers may find useful when investigating cranial biomechanics, to avoid oversimplification or incorporation of unnecessary complexities.

Publisher
School of Engineering and Computer Science, The University of Hull
Supervisor
Watson, Peter James; Fagan, M. J. (Michael J.), 1957-
Sponsor (Organisation)
University of Hull; Biotechnology and Biological Sciences Research Council (Great Britain)
Qualification level
Doctoral
Qualification name
PhD
Language
English
Extent
12 MB
Identifier
hull:17879
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