A new biomechanical approach on cranial sutures function: The role of contact elements in linear and non-linear models

<p>Understanding cranial sutures and how they relieve and dissipate stress is essential to assess their role in cranial biomechanics and to develop highly accurate predictive models. This involves examining how ontogeny affects cranial sutures, as well as their morphology and function, and how these changes through time may impact essential biomechanical loadings such as chewing or direct biting. In this work we study the cranial sutures of <em>Crocodylus niloticus</em> in detail using contact elements under finite element analysis. Contact elements permit the creation of a physical relationship between two bones that are in contact and even to configure these relationships, e.g. in terms of movement or flexibility. The definition of bone contacts may require linear and/or non-linear computational solutions to attain higher accuracy. Herein, skull geometry is tested to determine how they may be altered by different types of contacts under various conditions. As predicted, the absence of sutures or cranial kinesis leads to a reduction in stress distribution across the skull, whereas sutures and cranial kinesis help the skull relieve stress and prevent certain bones from sustaining high stress levels. The type of contact used in individual sutures has a significant effect on the models' outcome. Additionally, feeding behaviors significantly impact cranial biomechanics, reflecting the influence of other variables that may be applied to the models.  As highlighted by the results, in order to obtain accurate results when analyzing fossil taxa, the nature of the cranial sutures should be taken into account. Therefore, developing predictive models based on living taxa is invaluable because it facilitates the study of extinct taxa for which there is a lack of information on the fibrous joints due to poor (or non-) preservation in the fossil record.</p>