AbstractA study of the tolerance of the facial bones to blunt impact has been conducted for the purpose of determining the mechanics and important parameters affecting fracture. Such information is urgently needed for the safe design of vehicles and protective equipment, and would serve a useful purpose as an aid in the diagnosis and treatment of facial injuries. Work to date has been concentrated around the zygomatic bone because of its amenability to mathematical analysis and susceptibility to damage due to its relative fragility and prominence. The force to fracture the bone has been found to be time dependent. For example, high forces up to 1,000 pounds can be tolerated for extremely short time durations of 3 milliseconds or less. Impacts lasting beyond 4 milliseconds produce fracture near 200 pounds. These figures are for a 1 inch square area, and it has been found that for impulses lasting longer than 4 milliseconds the tolerance of the zygomatic bone can be raised by a factor of 150 to 250% if the load is distributed over the entire bone. A linear fracture around one zygomatic bone has been found not to affect the structural integrity of the opposite side of the face, which fact has been very useful in comparing parameters on the same cadaver. In comparing the impact strength of three facial bones on each of four cadavers, the frontal bone has been found to tolerate a force three or four times higher than the mandible and zygomatic bone which are about equal.