Forearm and Humerus Fracture Tolerance
The dynamic injury tolerances for the female humerus and forearm were derived from dynamic three-point bending tests using 22 female cadaver upper extremities. The strain rates were chosen to be representative of those observed during upper extremity interaction with frontal and side airbags. The average moment to failure when mass scaled for the 5th% female was 128 ± 19 Nm. Using three matched forearm pairs, it was determined that the forearm is 21% stronger in the supinated position, 92 ± 5 Nm, versus the pronated position, 75 ± 7. Two distinct fracture patterns were seen for the pronated and supinated groups. To produce a conservative injury criterion, a total of 7 female forearms were tested in the pronated position, which resulted in the forearm injury criterion of 58 ± 12 Nm when scaled for the 5th% female. It is anticipated that this data will provide injury reference values for the female forearm during driver air bag loading, and the female humerus during side air bag loading.
REFERENCES:
Duma, S.M., Schreiber, P.H., McMaster, J.D., Crandall, J.R., Bass, C.R., Pilkey, W.D., "Dynamic Injury Tolerance for Long Bones in the Female Upper Extremity," Journal of Anatomy, Vol. 194, Part 3, pp. 463-71, 1999.Virginia Tech / Wake Forest University Center for Injury Biomechanics