INJURY BIOMECHANICS
Peter L. Lane, MD, FRCPC
INJURY BIOMECHANICS
INTRODUCTION
Why bother ? The science of stopping Some examples of different mechanics and the injuries they produce How we can learn more
WHY BOTHER ?
Accidents will happen People will get hurt We'll try to fix them
"ACCIDENT"
Sudden event Unpredictable Unavoidable
INJURY AS A DISEASE
AIDS/TB analogy Relative importance as a public health issue
Framework of analysis
CLINICAL RELEVANCE
Patterns of injury Predictive of severity and outcome Prevention/injury control
THE SCIENCE OF STOPPING
Speed doesn't kill stopping does dv/dt =
V
dV/dT
v e l o c i t y
time (msec)
dV/dT
v e l o c i t y
V = 15 g
time (msec)
dV/dT
v e l o c i t y
V = 100 g
time (msec)
THE 3 COLLISIONS
Vehicle with barrier bony structures with vehicle interior viscera with bony structures
SLOWING THE STOP
Environmental factors n median barriers n roadside obstacles n traffic flow
Vehicle factors n windshields n "friendly" interior n steering column Restraint systems n 3 point belts n air bags
CRASH TYPE - FRONTAL
CONTACTS
windshield
INJURIES
face brain neck bony thorax lungs, heart, great vessels abdominal viscera knee, femur, hip, pelvis foot, ankle
steering wheel
dash board
pedals, firewall
CRASH TYPE - SIDE
CONTACTS
window/pillar
INJURIES
face brain neck bony thorax lungs hip pelvis
door panel/intrusion
CRASH TYPE - REAR
CONTACTS
head rest up head rest down seat back shoulder belt on
INJURIES
scalp contusions usually soft tissue strain to neck
none
chest contusion flexion/rotation inj to C- spine
CRASH TYPE - FRONTAL
CONTACTS BELTS ON INJURIES
shoulder component clavicle bony thorax neck - flexion/rotation abdominal wall solid and hollow viscera - compressive above plus distraction L - spine
lap component
lap belt alone
OTHER CRASH TYPES
Rollover Ejection Motor cycle Bicycle Pedestrian
INJURY BIOMECHANICS
SUMMARY
Why bother ? The science of stopping Some examples of different mechanics and the injuries they produce How we can learn more
MORE TO BE LEARNED
Crash investigation
Correlation with trauma registry data
Collision data project
Vehicle changes
Road design
Clinical data
Mechanics of other causes