mechanism of injury (MOI)
the factors and forces that cause traumatic injury.
kinetics of trauma
the science of analyzing mechanism of injury.
kinetics
the branch of mechanics dealing with the motions of material bodies.
kinetic energy
the energy contained by an object in motion.
With a thorough understanding of mechanism of injury,
you can look at a damaged vehicle and determine what types of injuries the patient is likely to have experienced.
trajectory
the path of a projectile during its travel; a trajectory may be flat or curved.
dissipation of energy
how energy is transferred to the human body by the forces acting on it.
drag
the factors that slow a projectile.
profile
the size and shape of a bullet's point of impact.
cavitation
a cavity formed by a pressure wave resulting front he kinetic energy of a bullet traveling through body tissue; also called pathway expansion.
fragmentation
the breaking up of a bullet into small pieces on impact.
The energy contained in a moving body is called
Kinetic energy.
If you were hit by a rock thrown at a velocity of 1 foot per second, then hit by the same rock thrown at 2 feet per second, the rock thrown at 2 feet per second would be:
Four times as harmful as the rock thrown at 1 foot per second because velocity is squared.
A bullet fired from a gun does more damage than a knife propelled by a human hand because:
The bullet impacts the body at a higher velocity.
Which of the following is correct regarding acceleration and deceleration?
A faster change in speed results in more force exerted.
In the typical motor vehicle crash, there are actually three impacts. When responding to a motor vehicle crash, remember the:
Organ collision occurs when the occupant's internal organs move forward and strike the inside of the skull, chest, or abdomen.
Vehicle collisions are a common mechanism of injury. Important points to remember include:
Maintain a high index of suspicion if any passenger appears "dazed.
When caring for patients at a motor vehicle crash involving a frontal impact, remember:
The driver will continue to move forward at the same speed the vehicle was traveling.
Types of injuries you should suspect in frontal impact collisions include:
A separation of the cartilage connecting the ribs and the sternum, which can result in a torn intercostal artery.
Which of the following is correct regarding motor vehicle crashes involving rotational impact or a rollover?
Multiple systems injuries are common in rollover crashes.
After being hit by a vehicle, why will a child have a different pattern of injuries than an adult who was struck in an identical situation?
Adults tend to turn away from the impact, causing more injuries to the side of the body, whereas children will face the oncoming vehicle and sustain frontal injuries.
During an accident, the vehicle's airbag can cause eye, face, and
Head injuries.
A pedestrian hit by a car, or someone who has fallen onto a concrete pavement, are examples of the law of:
Inertia.
What are the most common types of impact seen in motorcycle accidents?
Head-on, angular, and ejection.
Properly secured car seats restrain a child during a collision. Which of the following is true regarding car seats?
Having the car seat facing backward, and in the reclining position, will reduce spinal cord injury during a collision.
Your patient was thrown from an ATV while traveling at approximately 20 mph. During your initial assessment, the patient tells you, "I landed flat on my feet with both knees straight." Other than the ankles and heels, where would you suspect that the pati
Lumbar spine.
Why is the exit wound of a bullet always larger than the entry wound?
As the bullet's energy dissipates into flesh, its kinetic energy is transferred to the tissues. This causes tremendous damage, called cavitation, in which blown-out tissue proceeds along the same trajectory as the bullet, only on a large scale. This cause
Penetrating injuries are caused by an object that can penetrate the surface of the body. When caring for a patient with a penetrating injury, it is important to remember:
The severity of injury caused by penetrating trauma is related to the velocity of the penetrating object.
Of fatal wounds that occur due to firearms, the majority occur to the torso and head. Which of the following is true regarding gunshot wounds?
Lung tissue is relatively tolerant of the cavitation caused by projectiles, as the spongy mass formed by the alveoli is easily movable.
Regardless of the cause, every explosion has three phases. These phases include:
The secondary phase, in which injuries are due to flying debris propelled by the force of the blast.
When we speak of the "golden hour," we mean that there should be no more than 1 hour's time from the time:
Of the injury until delivery of the patient into surgery.
The mechanism of injury refers to how:
A person was injured.
The rate at which a body in motion increases its speed is known as:
Acceleration.
The amount of kinetic energy a moving body contains is based on its mass and:
Velocity.
When caring for the victim of a motor vehicle collision, the EMT should suspect severe injuries if there was:
Another occupant killed.
Based on the mechanism of injury, a(n) ________ of suspicion can lead you to suspect severe injuries even if the patient's initial signs and symptoms do not indicate there are any.
High index
In the frontal impact motor vehicle collision, the driver will continue to move forward at _____ the vehicle is traveling.
The same speed as
A child who is about to be hit by a vehicle generally turns ________ the oncoming vehicle.
Toward
A shoulder harness belt worn too high can cause ________ compression and spinal fractures in a head-on collision.
Abdominal
The three types of impacts associated with motorcycle collisions are head-on, ______, and ejection.
Angular
mechanism of injury
a force or forces that may have caused injury
broken bones=falls and vehicle collisions
burns=fires and explosions
penetration of soft tissue=gunshot woulds
spinal injury=forcefull blow
kinetics of trauma
The science of analyzing mechanisms of injury..
Helps u predict the kind and extent of injuries as a basis for your priority decisions regaurding continuing assessment, care, and transport.
Trauma
trauma is nearly always the result of two or more bidies colliding with each other except for blast injuries
kinetics
study of forces producing or changing motion
kinetic energy
the energy an object has due to its motion
Mass and velocity
the amount of kinetic energy a moving body contains depends on two factors:
mass (Weight) and the bodys velocity (speed)
Kinetics engery calculation
Kinetic Energy= Mass(wieght in pounds * velocity ( speed in feet per second) squared divided by 2
formula ilustrates that as the mass of a moving object is doubled the kinetics energy is doubled too
law of inertia
Law stating that objects at rest remain at rest and objects in motion continue in a straight line unless acted upon by a net external force. newtons law
impacts
three types of vehicle collision impacts:
Vehicular collison- vehicle has stopped and gets bent out of shape
body collision- patient comes to quick stop on some parts or parts of the inside car causing injury to chest
organ collision- in which the patient
commmon mechanism of injury
vehicle collision, falls, penetrating gunshots or stabbings, and explosions
the fall is most common mechanism of injury accounting more then half of all trauma incidents
over one third of all deaths are vehicle collisions
high index of suspicion
a keen awareness that there may be injuries
high index of suspicions
-death of another occupant of the vehicle
-an unresponsive patient or a patient with ALOC
-intrusion of greater than 12 inches for the occupant site or greater than 18 inches anywhere else on vehicle
-ejection from motor vehicle
patient's chance of death
motor vehicle collision classification
Frontal impact, rear-end impact,rotational and rollover and lateral
frontal impact
-causes down-and-under(lower body) injuries
injuries to knees femur hips acetabulum and spine
-causes up-and-over(upper body) injuries injuries to chest neck abdomen
rear-end impact
-Neck injuries
-Back injuries
-Head injuries
-Chest injuries
body is propelled forward and the head and neck remain at rest
whiplash injury
lateral impact
vehicle can be tbone and crushed inward
injuries to head neck chest pelvis and abdomen
vehicle pedestrian collision
child -turn toward the vehicle and causing injury to the front of the body (femur chest abdomenand head
adult- turns away from vehicle impact to side of body fracture of tibia and fibia
airbags
deployed within ten inches of the head or neck significstn injruy has occured
motorcylce collisions impacts
head on impact it tips forward travels into handlebars
angular impact rider strikes an object that is protruding out hits is at an angle
ejection
laying the bike down
bike is turned sideways with the drivers leg dragging on the pavement
Falls
most common MOI sevrity depends of distance surface and part of body impacted first
20 feet fall severe for adult
10 feet for child
feet first falls
causes energy to travel through the skeletal sysytem fractures of heels dislocations of ankles are common. if knees are flexed at the time of the impact the majority of energy will be dissipated at the knees and will preserve the rest of the skeletal syst
head first falls
head maybe forcilbly hyperextended which can cause extensive damage to cervicla spine
penetrating injuries
objects that can penetrate : bullets darts nails knives amount of kinetic energy transferred at the time of pentration determines damage it potetnilly can cause
classified as low medium or high velocity
low velocity
knives stabbing an slashing knife size
medium high velocity
pellets or bullets medium shotguns high rifle
trajectory
path taken by a projectile; Ex. trajectory of a bullet usually curved path but faster the bullet more flat path
dissipation of energy
How energy is transferred to the human body by the forces acting on it.
Drag-factors that slow the bulletdown such as wind resistance
profile- impact point of the bullet is its profile greater the size of impact point the more energy transferred
cavitatio
gunshot wounds
suspect both thoracic and abdominal injury if the entrance wound is between the nipple line and the waist
blast injuries
Can occur as a result of explosions. Regaurdless of the cause, every explosion has 3 phases: Primary, secondary, & tertiary.
Primary Phase Injuries: due to the pressure wave of the blast affect the gas containing organs Lungsstomach intestines inner ears
Golden period
The time from injury to definitive care, during which treatment of shock and traumatic injuries should occur because survival potential is best
platinum 10 minutes
optimal time duration on scene
PASG
Pneumatic Anti-Shock Garment; external bleeding control from lower extremities, indirect pressure for internal bleeding in pelvic and abdominal cavities used for decompensated shock with systolic less than 90mmHg