Force/Deflection and Fracture Characteristics of the Temporo-parietal Region of the Human Head

Reconstruction of real world head injury accidents resulting from falls using multibody dynamics

“…The MADYMO default curves are based on tests performed on the EEVC headform, while the alternative values are based on impacts carried out by Yoganandan et al [16] using unembalmed cadaver heads. Yoganandan's force-deflection characteristics are consistent with those estimated by Allsop et al (17) and Manavais et al (9) for skull bone -ground impact interactions. Thus it is reasonable to suggest that these figures are more realistic.…”

“…They are also not excessively high considering that all of these people sustained moderately severe head injury. Forces on the head, similarly, fall within more acceptable levels compared to the literature, and the only case that still exceeds the highest fracture limit found by Yoganandan et al [16] and Allsop et al [17] (Case 3) is one that actually did have skull fracture. With regards to angular acceleration figures for these simulations, they do reduce significantly, but not by the same factor that linear acceleration does.…”

“…Thomson et al [25] found angular acceleration values of between 7 and 30 krad/s 2 in reconstructions of severe head injury accidents involving vehicles). Force values for all of these simulations apart from Case 1 also exceed the highest tolerance limits established for skull fracture (14.1 kN [16] or 17.0 kN [17]), with fracture actually only occurring in two cases. In many simulations, these limits are exceeded by a great amount -enough to suggest much more extensive fracture of the skull than the relatively simple linear fractures present in the two cases showing skull fracture.…”

“…When results from the simulations presented here are compared to the upper and lower limits for contusion, acute subdural haematoma and subarachnoid haematoma from Auer et al [21], and skull fracture tolerance limits from Yoganandan et al [16] and Allsop et al [17], results for the simulations using the default head contact characteristics tend to fall above the upper tolerance curves, or between the lower and upper tolerance curves. Results for almost all of the simulations using the alternative head contact characteristics tend to fall between the two.…”

“…Failure loads ranged between 8.8 kN and 14.1 kN, with an average of 11.9 kN. Allsop et al [17], carried out temporo-parietal impacts on 31 unembalmed cadaver heads with two types of flat rigid impactors -one circular and 2.54 cm in diameter, the other a rectangular plate 5 x 10 cm. Fracture force for the small circular plate ranged between 2.5 and 10.0 kN with an average of 5.2 kN.…”