Validity and sensitivity of a human cranial finite element model: Implications for comparative studies of biting performance

Toro-Ibacache, Viviana; Fitton, Laura C.; Fagan, Michael J.; O'Higgins, Paul

Abstract

Finite element analysis (FEA) is a modelling technique increasingly used in anatomical studies investigating skeletal form and function. In the case of the cranium this approach has been applied to both living and fossil taxa to (for example) investigate how form relates to function or infer diet or behaviour. However, FE models of complex musculoskeletal structures always rely on simplified representations because it is impossible completely to image and represent every detail of skeletal morphology, variations in material properties and the complexities of loading at all spatial and temporal scales. The effects of necessary simplifications merit investigation. To this end, this study focuses on one aspect, model geometry, which is particularly pertinent to fossil material where taphonomic processes often destroy the finer details of anatomy or in models built from clinical CTs where the resolution is limited and anatomical details are lost. We manipulated the details of a finite element (FE) model of an adult human male cranium and examined the impact on model performance. First, using digital speckle interferometry, we directly measured strains from the infraorbital region and frontal process of the maxilla of the physical cranium under simplified loading conditions, simulating incisor biting. These measured strains were then compared with predicted values from FE models with simplified geometries that included modifications to model resolution, and how cancellous bone and the thin bones of the circum-nasal and maxillary regions were represented. Distributions of regions of relatively high and low principal strains and principal strain vector magnitudes and directions, predicted by the most detailed FE model, are generally similar to those achieved in vitro. Representing cancellous bone as solid cortical bone lowers strain magnitudes substantially but the mode of deformation of the FE model is relatively constant. In contrast, omitting thin plates of bone in the circum-nasal region affects both mode and magnitude of deformation. Our findings provide a useful frame of reference with regard to the effects of simplifications on the performance of FE models of the cranium and call for caution in the interpretation and comparison of FEA results.

Citation

Toro-Ibacache, V., Fitton, L. C., Fagan, M. J., & O'Higgins, P. (2016). Validity and sensitivity of a human cranial finite element model: Implications for comparative studies of biting performance. Journal of anatomy, 228(1), 70-84. https://doi.org/10.1111/joa.12384

• Journal Article Type: Article
• Acceptance Date: Aug 24, 2015
• Online Publication Date: Sep 23, 2015
• Publication Date: Jan 1, 2016
• Deposit Date: Apr 7, 2016
• Publicly Available Date: Apr 7, 2016
• Journal: Journal of anatomy
• Print ISSN: 0021-8782
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 228
• Issue: 1
• Pages: 70-84
• DOI: https://doi.org/10.1111/joa.12384
• Keywords: Digital speckle interferometry, Finite element analysis, Finite element model validation, Human cranium
• Public URL: https://hull-repository.worktribe.com/output/435231
• Publisher URL: http://onlinelibrary.wiley.com/doi/10.1111/joa.12384/abstract
• Additional Information: This is the peer reviewed version of the following article: Toro-Ibacache, V., Fitton, L. C., Fagan, M. J. and O'Higgins, P. (2016), Validity and sensitivity of a human cranial finite element model: implications for comparative studies of biting performance. J. Anat., 228: 70–84. doi:10.1111/joa.12384, which has been published in final form at http://dx.doi.org/10.1111/joa.12384. This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.
• Contract Date: Apr 7, 2016