Finite element model of a fetal skull subjected to labour forces

Abstract

The objective of this research is to study the deformation of a human fetal skull when subjected to labour forces. The shape of the fetal skull is recovered from a laser-scanned replica model. A combined technique of thin-plate spline surface fitting and an advancing front triangulation method provide a valid mesh model for finite element analysis. The skull is assumed to be a shell object and contains about 64,000 shell elements. The area around the parietal bones is subjected to a pressure load, exerted by the uterine cervix during the first stage of labour. The analysis investigates the influence of four parameters in the model. The resulting deformations agree with previous findings in terms of shape of deformation but are smaller in terms of degree of deformation. This may imply that moulding of the fetal skull during the birth process cannot be solely modelled by the short-time effect of a static load but effects such as hyper-elastic behaviour of the sutures, visco-elastic behaviour of the cranial bones and sliding contact between the head and surrounding tissues should be considered.