Finite element analysis of infant brain expansion and muscle
activation shows the importance of cranial sutures for healthy skull growth
Louisa Hulls1, Mehran Moazen2, Alana C Sharp3
1 Human Anatomy Resource centre, University of Liverpool, Liverpool, UK; 2UCL Mechanical Engineering,
University College London, UK; 3Institute of Life course and Medical Sciences, University of Liverpool, UK
•Craniofacial sutures are unique joints consisting of soft connective tissues between the skull
bones. They are important sites for bone growth during development, and for absorption of
mechanical stress, but their mechanical function is not well understood.
•Craniosynostosis is a congenital condition causing premature fusion of one or more cranial
sutures (Figure 1), which can lead to head malformations and brain damage.
•Corrective surgery, including cranial vault remodelling, fronto-orbital advancement or spring-
mediated cranioplasty, aims to separate the fused cranial bones, restore head shape, and
allow for normal cranial development.
•It is therefore important to understand the role sutures play in skull function and growth.
Material and Methods
Conclusions and Future Research
•Computational modeling can reveal important biomechanical relationships between craniofacial sutures and mechanical strain.
•FE stimulations show that sutures are important sites for cranial strain during brain expansion and masticatory muscle activation in infants.
•Higher strain in the patent sutures reduced strain in the surrounding bone.
•The frontal suture is particularly important as a strain sink during jaw muscle activation.
•Further research is needed to enhance our understanding of individual suture synostosis to explore patient-specific craniosynostosis.
•Our findings suggest FE analysis has the potential to improve our understanding of the biomechanical environment of the infant skull during
growth and could be used as a clinical tool for planning appropriate treatment strategy and optimising recovery for patients with
•We applied finite element (FE) analysis to an infant skull model
developed by Libby et al. (2017). The specimen used to create the
FE model was obtained from the archaeological collection at the
University of Dundee.
•The 3D FE model contained bone, suture and intracranial volume
(ICV) as separate materials (Figure 2).
•ICV expansion (modelled as thermal expansion) and jaw muscle
activation were simulated in Abaqus CAE 6.14 (SIMULA TM) FE
•We simulated “fused” sutures by applying the material properties
of bone to the suture areas.
•We then compared the model with fused and non-fused cranial
sutures to explore the biomechanical effect.
Figure 2. (a) CT sagittal section of an infant skull; (b) 3D FE model with bone (green), cranial
sutures (red) and internal ICV (unseen) materials. Mechanical loads for the temporalis and
masseter are shown as arrows.
•There was significantly higher strain in surrounding bone in the
fused model compared to the unfused model (Figure 3) suggesting
fusion of sutures causes bone deformation due to the loss of
compliant soft tissue sutures.
•During bilateral temporalis and
masseter muscles activation,
tensile strain was significantly
higher at the frontal suture in the
unfused model compared to the
Figure 4 (left). Tensile strain distribution during
bilateral muscle activation for fused (a) and
unfused (b) suture models.
0.05ε 0.08ε 0.15ε 0.25ε
Figure 3. Tensile strain distribution during ICV expansion for fused (a) and unfused (b) suture
models. Blue shows areas of low strain, red shows high strain at respective limits and grey
represents strain above this upper limit show under each model.
Libby J. et al. (2017) Modelling human skull growth: a validated computational model: Journal of the royal society interface; Cohen M, & MacLean R. (2000) Craniosynostosis: Diagnosis, Evaluation, and
Management. Journal of Medical Genetics, 37:727; Malde, O. et al. (2019) An Overview of Modelling Craniosynostosis Using the Finite Element Method. Molecular Sindonology, 10:74-82.
•FE skull model with fused
(craniosynostosis) sutures and
non-fused (normal) sutures.
•Forces experienced during
brain growth and activation
of masticatory muscles.
•Tensile strain distribution
between these two scenarios in
our model with and without