Clinical Findings and Experimental Studies
Clinical findings suggest that most injuries in absence of skull fracture occur in the frontotemporal basal area, possibly, as a consequence of frictional forces between the skull and brain tissue in that area.
In vivo experiments with animals have been carried out by Krave et al. (2005) in order to elucidate the development of pressure gradients on the brain tissue. These results show the development of high transient negative pressures depending on the intensity of the impact. Studies on human cadavers subjected to frontal impact have also been carried out to measure the intracranial pressures [Nahum et al., 1977; and Trosseille et al., 1992].
Recently, measurements of accelerations and deformations of human brain have been carried out. Bayly et al. (2002) measured the linear and angular accelerations that a soccer player’s head experiences due to an impact. Bayly et al. (2004, 2006) estimated the strain fields in a gel experimental model as well as euthanized and anesthetized rats. The methodology employed was based on non-invasive techniques that rely on magnetic resonance images. Bayly et al. (2005) investigated the brain deformation in humans during mild, but rapid, deceleration of the head. The study has provided quantitative images of acceleration-induced strain fields in the human brain, which can be useful in validating numerical models of brain trauma. The results have provided evidence for the basic mechanism based on brain rotation constrained by basal and frontal tethering.
