Kinematics
of Trauma
Kimberly Ann Holmes Kenney
RN, CNS-Rx, MS(N), MS
CCRN, CEN, CFRN, NREMT-P
Objectives

Discuss the laws of energy and motion.

Discuss trauma associated with blunt
impact and penetrating injury.

Overview of the effects of energy
distribution in MVCs.

Review the kinematics of blast and violent
injuries.

Use kinematics to predict injury patterns.
Kinetic Energy
mass (weight) x velocity (speed)2
KE =
2
or
mv2
KE =
2
Kinetic energy is the energy of motion.
Example of Kinetic Energy
The KE of a 150-lb. person traveling
at 30 mph would be:
150 x 30 x 30
2
= 67,500 KE units
Velocity vs. Mass
 150 lb. person traveling at 30 mph = 67,500 KE units
 180 lb. person traveling at 30 mph = 81,000 KE units
 150 lb. person traveling at 40 mph = 120,000 KE units
What is more important:
velocity or mass?
Velocity
Newton’s First Law of Motion
 A body at rest will stay at rest.
 A body in motion will remain
in motion.
 Unless what?
Newton’s First Law and Blunt Trauma
 Car strikes pole.
 Driver continues moving forward.
 Anterior surface of body strikes steering
wheel.
 Posterior body continues moving forward.
 Organs compressed within body.
Law of Conservation of Energy
 Energy cannot be created.
 Energy cannot be destroyed.
But, energy can
0
change forms
and
can be transferred.
Can you give
an example?
How does the
Law of Conservation of Energy
pertain to trauma?
Can you give some examples?
Deceleration and Acceleration
Compression Injury
Deceleration and Acceleration
Shear Injury
Organ Injury
In a 50 mph MVC, what types injuries would
occur if the patient were to strike the windshield?
Head Injury
 Fractures.
 Ligamentous injuries.
 Soft tissue injury.
 Brain injury.
 Cord damage.
Torso Injury
 Rib fractures.
 Heart & lung
damage.
 Abdominal organ
damage.
 Major vessel
damage.
Extremity Injury
 Fractures.
 Ligamentous injury.
 Soft tissue injury.
Types of Motor Vehicle Collisions
 Frontal impact.
 Lateral impact.
 Rotational impact.
 Rear impact.
 Rollover.
What type of injury patterns might
you see in a frontal impact?
Frontal Impact - Occupant Pathways
What injuries would you expect with an
up and over pathway?
Injuries with Up & Over Pathway
continued...
 Head injuries.
 Spine injuries.
 Chest injuries.





Fractures.
Pneumothorax.
Hemothorax.
Contusions.
Great vessel injury.
Injuries with Up & Over Pathway
continued...
 Abdominal injuries.



Solid organs.
Hollow organs.
Diaphragm.
 Fractured pelvis.
Frontal Impact - Occupant Pathways
What injuries would you expect with
a down and under pathway?
Injuries with Down & Under Pathway
 Posterior knee/hip dislocations.
 Femur fractures.
 Lower extremity fractures.
 Pelvic/acetabular fractures.
Rear Impact
What types of injuries would you expect?
Lateral Impact
What types of injuries would you expect?
Body Motion during Lateral Impacts
 Neck
 Chest
 Pelvis
Rotational Impact
What types of injuries would you expect?
Rollover
What injury patterns might you see
following this collision?
Lap Restraint Device
 Properly positioned lap restraint.
 Improperly positioned lap restraint.
What types of injuries
should you anticipate?
Lap & Shoulder Restraint System
 Shoulder harness only; lap belt not used.
(Victim moves down and under).
 Lap restraint only; shoulder harness not
used. (Victim moves up and over)
What types of injuries
should you anticipate?
Airbag Deployment
 What types of injuries would
you expect to see?
 What injuries would occur in a
second collision?
Airbag Deployment
 What concerns would you have
about a:

Small patient?

Child in a car seat?
Motorcycle Collisions
Mandatory helmet laws
have been associated
with up to 300% fewer
head injuries and
deaths.
Types of Impact: Frontal/Ejection
How many impacts did this collision involve?
What types of injuries would you expect to see?
Types of Impact: Lateral
How many impacts did this collision involve?
What types of injuries would you expect to see?
Pedestrian vs. Motor Vehicle
How would the injury patterns differ
between the adult and the child?
Falls
 Impact surface.
(Harder surface = greater injury.)
 Height.
(Greater height = greater injury.)
 Falls from a distance of more than
three times the patient’s height
produce critical injuries.
Falls
 Deceleration injuries.
 Liver.
 Aorta.
 Spleen.
 Kidney.
Landing Feet First
(Don Juan Syndrome)
 Injuries seen in patients landing
feet first:
Bilateral heel fractures.
 Ankle fractures.
 Distal tibia/fibula fractures.
 Knee dislocations.
 Femur fractures.
 Hip injuries.
 Spine compression fractures.

Landing Arms/Hands First
 Physical findings:
 Colles’
fractures of wrists.
 Shoulder
dislocations.
 Fractures
of the clavicles.
Landing Head-First
 Physical
findings:

C-spine
injuries.

Facial injuries.

CNS damage.
Sports & Recreational
Activity Mechanisms
 Acceleration
 Deceleration
 Hyperextension
 Hyperflexion
 Twisting
What types of sporting or
recreational injuries are
 Falling
common to your area?
Predicting Sports-Related Injuries
 Kinematics & forces involved.
 Equipment contributing to injury.
 Involvement of protective equipment.
 Nature of the sport.
Blast Injuries
 Warfare.
 Civilian areas.








Mines.
Shipyards.
Chemical plants.
Tank trucks.
Refineries.
Fireworks firms.
Silos.
LP gas tanks.
Do you have any of
these in your area?
Blast-Related Injuries
 Three mechanisms of injury:

Primary.

Secondary.

Tertiary.
Primary Phase Injuries
 Cause: pressure wave from blast.
 Affected area: gas-containing organs.
 Injuries:





Pulmonary bleeding.
Pneumothorax.
Air emboli.
Perforation of the GI tract.
Burns.
 Death may occur in absence of outward signs.
Secondary Phase Injuries
 Cause: flying debris.
 Affected area:
Body surface.
 Skeletal system.

 Injuries:
Lacerations.
 Fractures.
 Burns.

Tertiary Phase Injuries
 Cause: victim thrown against an
object.
 Affected area: area of impact or
referred energy.
 Injuries: similar to those sustained
in a vehicle ejection.
Penetrating Trauma
 Physics.
 Weapon velocity.
 Bullet design.
Penetrating Trauma
 Newton’s First Law and ballistics:


Bullet in brass cartridge is at rest.
Bullet propelled by rapid
combustion of powder.

Bullet leaves barrel of gun.

Bullet strikes a body.

Bullet transfers energy to victim.
Low-Energy Injuries
 Low velocity.
 Usually hand-driven
weapons.
 Less secondary trauma.
 Multiple wounds from a
single weapon.
Low-Energy Penetrating Wounds
How does the length
of the weapon relate
to the cone of
damage?
Assessment of Low-Energy Injuries
 Type of weapon involved.
 Path of weapon.
 Depth of penetration.
 Number of wounds.
 Underlying anatomy.
Medium-Energy Penetrating Injuries
High-Energy Penetrating Injuries
How do these weapons differ
from handguns and shotguns?
How do the wounds
differ internally and
externally?
Projectile - Frontal Area
 The larger the frontal area of the
projectile, the greater the damage.
 The larger the cavitation and the
greater the damage, the greater the
exit wound.
Gunshot Wounds - Cavitation
Reformation by
elastic tissue
Direction of travel
Permanent
cavity
Temporary
cavity
Bullet
Compression
and crush
Gunshot Wounds
Describe the difference between
entrance and exit wounds.
Tumbling Projectiles
 Some projectiles are designed to tumble.
 Tumbling creates greater tissue damage
and more tissue destruction.
Fragmentation
The shotgun round is the ultimate
in fragmentation.
Considerations for Penetrating Trauma
 Scene safety.
 Patient care is the priority!
 Weapon type.
 Range at which weapon was fired.
 Number of entrance and exit wounds.
 Underlying anatomy and track.
 Crime scene preservation.
Kinematics Summary
The cornerstone of assessment
is early consideration of
kinematics to predict hidden
injury.