Research has demonstrated that the bones of the skull are thicker in regions associated with high musculoskeletal stress (Distriquin et al., 2020). With the application of ascending spinal pressures and descending musculofascial tractions, bone growth formation is greatest at the base of the skull (Distriquin et al., 2020). Several researchers have examined the difference in resistance between skull bones and sutures (Distriquin et al., 2020). One study found cranial suture to be 35 times more elastic than cranial bone in a pediatric population (Distriquin et al., 2020). This allowed the authors to deduce that pediatric cranial sutures will displace 30 times more prior to causing a pediatric cortical bone fracture (Distriquin et al., 2020). In adults, the resistance properties found with pediatric sutures are comparable to that of the skull vault (calvaria), meaning that there is a notably lower risk of deformation of the skull vault (Distriquin et al., 2020).
Another study, analyzed the effect of the sinuses with relation to maxillary, zygomatic and frontal impacts (Distriquin et al., 2020). A finite elemental model was employed to measure the displacement of bones (in centimetres) from the impact (Distriquin et al., 2020). The skull follows the same laws of physics that adhere with other materials: sutures contain elastic resistance that allow interosseous displacement up to the elasticity limit (3 cm for 4 × 105 Newton) (Distriquin et al., 2020). Sutures will bend when force is applied and ultimately break if it surpasses the elasticity limit, resulting in a diastatic fracture (Distriquin et al., 2020).
Other researchers have also used a finite elemental model to examine the differences in suture resistance to traction/compression based on their morphology (sinusoidal or straight) (Distriquin et al., 2020). The reason behind this is the sutures of the skull base are straight as opposed to the sutures of the skull vault, which are sinusoidal (have interdigitations) (Distriquin et al., 2020). The results demonstrated that sinusoidal sutures are able to withstand forces better than that of straight sutures (Distriquin et al., 2020). Additionally, forces are typically perpendicular with traumatic injuries and cranial vault sutures are angled whereas skull base sutures are more vertical (Distriquin et al., 2020). Therefore, calvaria sutures absorb more force by means of displacement with subduction of bone plates, unlike the basilar sutures which are more likely to distort by means of vertical and horizontal slipping (Distriquin et al., 2020). These studies exemplify that the skull is a heterogenous structure with anisotropic resistance (Distriquin et al., 2020). They also demonstrate that the base of the skull is subject to greater stress and deformation capacity, compared to the calvaria (Distriquin et al., 2020).
References
Distriquin, Y., Vital, J. M., & Ella, B. (2020). Biomechanical analysis of skull trauma and opportunity in neuroradiology interpretation to explain the post-concussion syndrome: literature review and case studies presentation. European Radiology Experimental, 4(1), 1-9. https://doi.org/10.1186/s41747-020-00194-x