The dynamics of shaken baby syndrome

Abstract

Shaken Baby Syndrome is a form of child abuse estimated to occur to one in 20,000 babies and presumed to occur when a carer cannot cope with a constantly crying child and so gives it a sharp shake. This causes the brain to move within the skull, stretching and possibly tearing the veins that bridge the fluid filled gap. To better understand this condition, experiments were performed to measure the mechanical properties of bridging veins followed by detailed mathematical modelling of the motion of a baby’s brain in response to shaking. Few finite element models of shaken baby syndrome exist, and those either ignore the fluid surrounding the brain or model it as a soft solid. The importance of modelling the fluid properly is demonstrated, and the reliability of MSC.Dytran’s fluid-solid interaction modelling is confirmed. The first three-dimensional finite element model of shaken baby syndrome which accurately includes the cerebrospinal fluid is created and used to estimate tolerance criteria for causing subdural haematoma by shaking. This research concludes that shaking of a baby could produce bridging vein strain close to the tolerance for failure and hence should be considered a possible cause of subdural haematoma.