Lateral head impacts and protection of the temporal area by bicycle safety helmets.
BACKGROUND
The protective effectiveness of bicycle helmets has been demonstrated in several epidemiologic studies. However, the temple region is only minimally covered by most helmet models. Impact tests were performed on human cadavers to investigate whether current bicycle helmets are capable of preventing direct contact on the temporal area in side impacts.


METHODS
Lateral head impacts, corresponding to a force load of 15,000 N on an nonhelmeted head, were applied on 11 helmeted cadavers by a steel pendulum with a flat impact surface, and the contact between the impactor plate and the temporal and zygomatic area was investigated by means of paint transfer. In eight tests, a common design bicycle helmet was used, whereas in three tests the helmets provided larger temporal coverage (temporal helmet edge <10 mm above Frankfort plane). The skulls were inspected for fractures.


RESULTS
In seven of the eight tests with common design bicycle helmets, contact had occurred and in one of these a skull fracture was seen. The helmets with a larger temporal coverage consistently prevented such contact loading.


CONCLUSIONS
The common designs of commercially available bicycle helmets do not prevent direct contact loading on the temporal and zygomatic arch region and this contact loading is potentially harmful. The present preliminary study strongly questions the effectiveness of these helmets in providing accurate protection of the temporal and zygomatic area.
Depreitere
Bart
B
Division of Neuroanatomy and Experimental Neurosurgery, Katholieke Universiteit Leuven, Belgium. bart.depreitere@uz.kuleuven.ac.be
Van Lierde
Carl
C
Vander Sloten
Jos
J
Van der Perre
Georges
G
Van Audekercke
Remy
R
Plets
Christiaan
C
Goffin
Jan
J
D001265:Athletic Injuries / Q000517:prevention & control; D001642:Bicycling; D001696:Biomechanical Phenomena; D002102:Cadaver; D016489:Head Injuries, Closed / Q000517:prevention & control*; D006260:Head Protective Devices; D006801:Humans; D012887:Skull Fractures; D013701:Temporal Bone / Q000293:injuries*