Brain Fluidity |
**Fluidity and Geometry** |
Stress-strain Relation |
Resonance Effect |
Grey/White Boundary

### The role of the brain fluidity and geometry during traumatic head rotations

**Fluidity and Geometry 1** |
Fluidity and Geometry 2

In the nonlinear fluid TBI model, the brain geometry and topology impact the
character of the solutions to a much greater extent than in the Kelvin-Voigt
(K-V) linear solid body model. For instance, during the sideways rotational
deceleration of a head about its center of mass, both models predict that the
corresponding vector fields reflect the elliptic shape of the skull's
horizontal cross-section without the *falx cerebri*, and the turbulent
flow characteristic for the solutions of the nonlinear model appears only near
the minor imperfections of the elliptical shape of the cross-section (left
panels). The introduction of the *falx cerebri* leads to dramatic
differences between the predictions of both models (right panels). The nonlinear
model predicts not only more turbulent flow but also quite a different
distribution of the vector field in each part of the disconnected domain. The
latter indicates that its solutions are very sensitive to the asymmetry of the
domain's boundary. In fact, the extensive turbulent flow appearing in the front
of the sagittal cross-section during a forward head rotation is due to the
concave shape of this cross-section. Thus, the specific localization of Diffuse
Axonal Injuries may strongly depend on the traumatic motion's characteristics.

Frames Buffered 0%