Fatal Facts About Helmets
A Neurosurgeon Speaks the Truth
During World War II, an English neurosurgeon named Cairns compared the
head injuries of crashed motorcyclists wearing helmets. Cairns, a Professor
of Neurosurgery at Oxford
University, noted that helmeted
motorcyclists who had broken their facial bones had less serious brain
Clearly, some impact energy had been absorbed by the face or
the helmet. From those early studies, the suggestion came that all
motorcyclists should wear a helmet.
The only types available then were "inverted pudding bowl" styles that
barely covered the short hair style of the day.
These had an inner
lining of cork or pulp that was used
to absorb energy. During the
1960s, the fighter pilot style
became popular because it covered the
came in colorful fiberglass shells, and had better energy
absorption material inside. Gradually helmet standards arose to ensure
that helmets were constructed to a standard level
that assured adequate
impact performance in controlled
helmet impact tests.
During the 1970s, full-face helmets (fighter pilot style plus facial
protection) gained popularity. Manufacturers argued that if that
fighter pilot style helmet had a chin bar, then the
whole head and face
could be protected. But this presented
the helmet standards committees
with a dilemma:
How to test the performance of the chin bar component
when no one was sure about how far it should deflect upon impact? Some
said the chin bar should be soft and pliable. Others said it should be hard
The rigid school won, and efforts were made to
stiffen the chin bar by incorporating strong materials to increase its
Early medical reports of facial injury patterns in motorcyclists
supported the use of full-face helmets because hospital accident and
emergency departments were treating far fewer facial cuts and abrasions
among bikers wearing full facial
protection. Indeed, it became rare to see an injured motorcyclist
with a facial bone fracture if he wore a full-face
helmet. All was well for motorcyclists who came to hospitals
for treatment after a crash that involved a head impact.
But what about that ever-growing band of motorcyclists who didn't make
it to the hospital? Many died in helmets that
fitted well, were well
adjusted, and were firmly in place
at the time of the crash. Of course,
some of these had fatal chest and abdominal injuries, but too many seemed
dying from impacts they should have survived.
During the 1980s, reports from road accident research units worldwide
showed an increasing incidence of a particular
fatal skull injury among
motorcyclists wearing full-face helmets. This common fatal injury was a skull
- a severe crack across the bones on which the
To try to explain how these devastating injuries were
happening, some associates and I looked in depth at a small number of
motorcyclists who had been fatally injured
while wearing full-face
helmets. At this time, the latest
X-ray equipment available for
patients with head injuries
was computerized CT scanning (CAT scanning).
CAT scans could be converted into three-dimensional images to help plan
the surgery that crash victims often required.
Using CAT scanning
techniques, we compared the patterns
of injury among 50 motorcyclists
admitted to hospitals with
24 motorcyclists killed from similar impacts
during the same period. We retrieved the helmets worn and also studied
them with the CAT scanner.
Each motorcyclist's head was considered as a four-layered unit: 1) the
helmet, 2) the scalp and facial skin, 3) the skull and facial bones, and
4) the brain. Detailed scientific information was gleaned from each of
That information was then fed into a computer-based
coding system for analysis. In addition to the CAT scan information, a
detailed autopsy was performed on the
fatally injured group. An
review was also performed on the brain of
When analyzed, our results showed that motorcyclists with broken facial
bones usually had been wearing helmets
that gave little or no facial
protection. Furthermore, they had
little on the way of brain injury.
In contrast, those motorcyclists killed outright often had no facial injury, even if they suffered an impact to the front of the helmet. They did, however, have skull
base fractures and fatal brain injuries. Apparently, the blow to the chin bar had been transmitted to the chin strap, increasing its tightness sufficiently to drive the lower
jaw upward into the base of the skull. The upward force into the skull
base, then, may have caused the fracturing and subsequent brain damage.
The brain damage was concentrated at the critical brain stem region
where the spinal cord effectively "plugs into" the base of the brain. Damage in that region is usually instantly fatal.
How Helmets Can Kill:
1. Impact to the lower face bar is transmitted via the jaw to the skull.
2. The chin strap forces the jawbone upward. The brain stem is
3. The Helmet Rotates. This pattern of death emerged after four years
Were our findings only present by chance in the sample of motorcyclists
we studied? To find out, we performed a second study of 988 brains from
autopsies performed on road accident victims. These 988 included 36
cases of unequivocal brain stem injury. The proportion of motorcyclists
in that series was double the expected figure, and of the 15
motorcyclists, 13 were known
to have been wearing helmets at impact and 11
wearing full-face helmets. Furthermore, the principal
impact point was the chin bar in one of the bikers.
These findings strengthened the possibility that a blow to a rigid chin
bar could be transferred via the chin strap to the lower jaw and then to
the skull base, with fatal consequences to the fragile brain stem. If this were so, then how could it be prevented? In collaboration with
engineering scientists and computer-aided-design (CAD) experts, we
series of solutions. Essentially, they involved the
incorporation of an energy absorber into the chin bar of a full-face
helmet. This would reduce the impact energy transmitted to the brain stem and, hopefully, transfer a potentially fatal impact victim into the
survivable range. The wheels of change in altering safety designs move
excruciatingly slow, the the full-face helmet with a soft, pliable chin
bar extension ma8y be a suitable alternative.
Let's face it: A motorcyclist's helmet should be worthy of the head upon
which it rests.
Rodney D. Cooter, M.D.
( Dr. Rodney Cooter is currently the Staff Grader in Plastic Surgery at
St. James University Hospital, Leeds, United Kingdom. He trained for
five years at the Weapon's Research Establishment in South Australia
before completing a four-year training in engineering draftsmanship with Telecom Australia. He studied medicine at the University of Adelaide
for six years before commencing surgical training. During his surgical
training with the Australian Craniofacial Unit, developed an interest in the engineering aspects of injury to the head and face. In his doctoral
thesis-Craniofacial Fracture Patterns-he examined the effects of helmets on injury patterns. This article follows that intensive study. )