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Chp 24- Trauma Exam Questions With
Correct Answers.
The mechanism of injury (MOI) - answer✔is the way in which traumatic injuries occur; it describes the
forces (or energy transmission) acting on the body that cause injury.
Three concepts of energy are typically associated with injury (not including thermal energy, which
causes burns): - answer✔Potential energy
Kinetic energy
The energy of work
Work - answer✔-is defined as force acting over a distance.
-The energy of a moving object is called kinetic energy.Kinetic energy reflects the relationship between
the mass (weight) of the object and the velocity (speed) at which it is traveling, expressed as:Kinetic
energy = 1⁄2 mass × velocity2orKE = 1⁄2 m × v2
Newton's First Law - answer✔-Objects at rest tend to stay at rest and objects in motion tend to stay in
motion unless acted on by some force.
-Example:
In a car going 30 mph, the passengers and the car are moving at 30 mph. The passengers do not feel as
though they are moving because they are not moving relative to the car. However, when the car strikes
a concrete barrier and comes to a sudden stop, the passengers continue to travel at 30 mph. They stay
in motion until they are acted on by an external force such as the windshield, steering wheel, or
dashboard.
Newton's second law - answer✔Force (F) equals mass (M) times acceleration (A), that is: F = M × Ain
which acceleration is the change in velocity (speed) that occurs over time.The change in velocity with
respect to time generates the forces that cause injury.
-Example:
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In the second scenario, the driver is restrained with a shoulder and lap belt. His or her body stops during
the same period the car stops, which, allowing for the crushing of the front of the car, takes
approximately 0.05 second. The change in the driver's velocity is the same (30 to 0 mph), but the longer
period of deceleration results in a g force of 30 times that of gravity (one g force is the normal
acceleration due to gravity), rather than 300 g. This is still substantial, but it is much less than the force
experienced by the unrestrained driver. It is survivable.
Newton's third law - answer✔-For every action, there is an equal and opposite reaction.
-Example:
In the case of a dented A-pillar, the force of the driver's head was sufficient to dent the strong metal.
The head was essentially hit by an A-pillar traveling at 30 mph.When you notice a collapsed steering
wheel during scene size-up, suspect serious chest injuries even if the driver initially has no visible signs
of chest injury.
Kinetic Energy - answer✔Because KE = m × v2, the energy that is available to cause injury doubles when
an object's weight doubles and quadruples when its speed doubles.
-The speed of a bullet has a greater impact on producing injury than the mass (size) of the bullet.
-The amount of kinetic energy that is converted to do work on the body dictates the severity of the
injury.
-High-energy injuries often produce such severe damage that patients require immediate transport to
an appropriate facility to have any hope of survival.
Potential Energy - answer✔Potential energy is the product of mass (weight), force of gravity, and height
and is mostly associated with the energy of falling objects
Examples of significant MOIs include: - answer✔-Injury to more than one body system (multisystem
trauma)
-Falls from heights
-Motor vehicle and motorcycle crashes
-Car versus pedestrian (or bicycle or motorcycle)
-Gunshot wounds
-Stabbings
Blunt trauma - answer✔is the result of force to the body that causes injury without anything penetrating
the soft tissues or internal organs and cavities.
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is the result of force to the body that causes injury without anything penetrating the soft tissues or
internal organs and cavities. - answer✔-results in injury by objects that pierce and penetrate the surface
of the body and injure the underlying soft tissues, internal organs, and body cavities.
-It is important to consider unseen as well as visible, obvious injuries with either type of trauma.
-Damage to the underlying deeper tissues is often more significant.
The collision of the car against another car, a tree, or some other object - answer✔-Damage to the car is
perhaps the most dramatic part of the collision, but it does not directly affect patient care, except
possibly to make extrication difficult.
-The greater the damage to the car, the greater the energy that was involved and, therefore, the greater
the potential to cause injury to the patient.
-If there is significant damage to a vehicle, your index of suspicion for the presence of life-threatening
injuries should automatically increase.
-Such damage suggests the presence of high-energy trauma.
The collision of the passenger against the interior of the car - answer✔-The kinetic energy produced by
the passenger's mass and velocity is converted into the work of stopping his or her body.
-Like the damage to the exterior of the car, the injuries that result are often dramatic and usually
immediately apparent.
Common passenger injuries include: - answer✔-Lower extremity fractures (knees into the dashboard)
-Rib fractures (rib cage into the steering wheel)
-Head trauma (head into the windshield)
-Such injuries occur more frequently if the passenger is not restrained.
The collision of the passenger's internal organs against the solid structures of the body - answer✔-
Injuries that occur during this type of collision may not be as obvious as external injuries, but they are
often the most life threatening.
-As the passenger's head hits the windshield, the brain continues to move forward until it comes to rest
by striking the inside of the skull.
-This results in a compression injury to the anterior portion of the brain and stretching (or tearing) of the
posterior portion of the brain, known as a coup-contrecoup brain injury.
-In the thoracic cage, the heart may slam into the sternum, which may rupture the aorta and cause fatal
bleeding.
Vehicular Crashes: Significant MOIs are suggested by the following findings: - answer✔-Death of an
occupant in the vehicle