PHTLS CHAPTER 4: THE PHYSICS OF TRAUMA EXAM

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PHTLS CHAPTER 4: THE PHYSICS OF TRAUMA EXAM

QUESTIONS

Actual Qs and Ans - Expert-Verified Explanation -Guaranteed passing score -52 Questions and Answers

-Format: Multiple-choice / Flashcard

Question 1: Law of Conservation of Energy

Answer:

Energy cannot be created or destroyed

• energy is simply transferred
• example: vehicle stopping turns into friction energy with brakes, heat, collision

Question 2: stellate wound

Answer:

A star-shaped wound.-exit wound

• no abrasion on exit side

entry wound usually is a round or oval wound -abrasion on entry side

Question 3: motor vehicle crashes

Answer:

-most common form of blunt trauma

5 types:

• frontal impact

-rear impact -lateral impact -rotational impact -rollover

Question 4: kinetic energy

Answer:

energy of motion

• function of an object's mass and velocity

KE= 1/2(mv^2) increasing velocity since it is squared does way more to increase KE than mass mass

Question 5: blast waves

Answer:

energy associated with explosion in the form off kinetic energy -static and dynamic components static: blast overpressure: surrounds objects in field of explosion, loading them on all sides with shock front or shock wave that goes to a peak overpressure value

dynamic pressure: directional and experienced as a blast wind

-propels debris

Question 6: density

Answer:

fist colliding with more dense object (more particles per volume) like brick absorbs more energy than less dense material

3 types in tissues: air density (lungs and portions of intestine)

-water density (water and solid organs) -solid density (bones)

Question 7: Cavitation

Answer:

The formation of cavities in an organ or tissue

• occurs when force is applied that knocks tissues out of their normal place

temporary cavity: caused by stretching of tissues that occurs at time of impact

• returns once force has been exerted, depends on elasticity of tissue
• some turns into permanent

permanent cavity: left after temporary cavity collapses,

-visible destruction part of tissue

• amount of permanent cavity formation depends on elasticity of the tissue

Question 8: size of permanent cavity depends on:

Answer:

elasticity in the tissue struck

• liver is ridged and fractures, but muscle can form back to normal shape

Question 9: rear impact

Answer:

slower moving or stationary vehicle is struck from behind

• fast vehicle is called the bullet vehicle
• slow vehicle is called the target vehicle

energy of bullet vehicle transferred into the acceleration of the target vehicle -greater the difference in momentum of the two vehicles, the greater the force of initial impact hyperextension of the neck, shearing and stretching of ligaments in anterior neck

Question 10: blunt trauma

Answer:

energy is dispersed over wider area, no penetration occurs

two forces are involved:

-shear: organ changes speed faster than organ structure, causes parts to separate and tear

• compression: result of an organ or structure being directly squeezed between other organs or

structures: bowel being compression due to abdominal wall being crushed with seatbelt

Question 11: front impact

Answer:

up and over movement over steering wheel, can strike windshield or wheel -kidneys, spleen, liver are subject to shear injury as abdomen strikes the steering wheel

• aorta can tear

down and under path: knees strike the dashboard, face smashes into the steering wheel

-dislocation knee: can injure popliteal artery

• treatment can prevent distal leg ischemia

Question 12: Newton's Third Law

Answer:

For every action there is an equal and opposite reaction

- example: walking on ground, recoil of a shotgun

Question 13: Newton's First Law

Answer:

An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an outside force.

Question 14: Stopping distance

Answer:

distance before object stops -shorter and quicker stopping distance means more energy is transferred into occupants and more damage is done to pt -also applies to falls -aka softer material landing on with slower stopping time and longer distance=less damage (duh)

Question 15: pelvic fractures

Answer:

result of damage to external abdomen -may cause injury to bladder, lacerations of blood vessels in pelvic cavity Question 16: sports injury: assessing mechanism of injury questions

Answer:

-what forces acted on the victim and how

• what are the apparent injuries
• to what object or part of the body was the energy transmitted
• what other injuries are likely to have been produced by this energy transfer
• was protective gear worn
• was there sudden compression, deceleration, or acceleration
• what injury producing movements occurred

Question 17: three phases of traumatic event

Answer:

pre event: prevention

• pre existing conditions, patient's state of mind
• why did accident occur, what might make it more severe

event: mechanics that cause harm

post event: patient care phase

• phase begins as soon as impact from crash is absorbed by body
• complications related to the incident