Penetrating Trauma

Question 1

Ballistics

Answer 1

•  Study of the characteristics of projectiles in motion and effects upon objects impacted
•  Aspects of projectile motion
– Trajectory
– Energy dissipation

Question 2

Path of a Bullet

Answer 2

•  Bullet spins as it travels down barrel
– Rifling in barrel
– Allows bullet to travel straight with slight yaw
– Bullet departs barrel, spinning with a slight wobble or yaw
•  Weapon forced backward and absorbs energy
– Recoil

Question 3

Path of a Bullet

Answer 3

•  Remainder of energy propels bullet forward at a high rate of speed.
•  As bullet strikes object, it slows and energy is transferred to object.
–  Law of Conservation of Energy

Question 4

Trajectory

Answer 4

•  The path a projectile follows
•  Bullets are pulled down by gravity as the travel through the air
– Causes a curved path
– The faster the bullet the straighter the path

Question 5

Factors in Energy Dissipation

Answer 5

•   Drag
•   Cavitation
•   Profile
•   Stability
•   Expansion
•   Shape

Question 6

Energy Dissipation Drag

Answer 6

– Wind resistance

– The faster the bullet travels, the more drag it experiences

Question 7

Energy Dissipation Cavitation

Answer 7

– The outward motion of tissue due to a projectile’s passage
– Results in temporary cavity and vacuum
– Related to velocity and how quickly it gives up energy

Question 8

Stability

Answer 8

Location of bullet’s centre of mass affects it stability

Question 9

Bullet length increases bullet tumbling

Answer 9

–  Can reduce the accuracy of the shot

–  Reduced by rifling in barrel (spinning)

Question 10

Yaw

Answer 10

Gyroscopic effect on the center axis of the bullet that reduces tumbling

Question 11

Tumbling of bullet once it strikes object

Answer 11

–  Reduces kinetic energy

–  Greater tissue damage

Question 12

Expansion and Fragmentation

Answer 12

•   Results in increased profile
•   Mushrooming
•   Initial impact forces may result in fragmenting
•   Greater tissue damage

Question 13

Secondary Impacts

Answer 13

Energy exchange also affected by secondary impacts
– Bullet striking other objects can cause yaw and
tumble

Question 14

Body Armor (Kevlar)

Answer 14

– Transmits energy throughout entire vest resulting in blunt trauma 
–  Increased risk for  
•  Myocardial Contusion 
•  Pulmonary Contusion 
•  Rib Fractures

Question 15

Handgun ammunition

Answer 15

–  Blunt, more resistant to travel through human tissue

–  Releases kinetic energy more quickly

Question 16

Rifle Bullets

Answer 16

– More pointed, cut through tissue more easily

–  If the bullet tumbles, may exchange energy more rapidly

Question 17

Fragmented bullet

Answer 17

– Will give up energy more quickly through erratic pathways

Question 18

Handgun characteristics

Answer 18

– Small caliber, short barrel, medium­‐velocity
– Effective at close range
– Severity of injury based upon organs damaged

Question 19

Rifle characteristics

Answer 19

– High-­velocity, longer barrel, large caliber

–  Increased accuracy at far distances

Question 20

Assault Rifle Characteristics

Answer 20

–  Large magazine, semi­‐ or full­‐automatic
– Similar injury to hunting rifles
– Multiple wounds

Question 21

Shotgun Characteristics

Answer 21

– Slug or pellets at medium velocity
– 00 (1/3”) to #9 (pin head sized)
–  Larger the load, the smaller the number of projectiles
– Deadly at close range

Question 22

Knives & Arrows Characteristics

Answer 22

–  Low-­energy & low-­velocity
– Damage related to depth and angle of attack
– Movement of the victim can increase damage
– The extent of the damage is ojen difficult to assess

Question 23

Projectile Injury Process

Answer 23

•  Tip impacts tissue
•  Tissue pushed forward and to the side
– Tissue collides with adjacent tissue
•  Shock wave of pressure forward and lateral
– Moves perpendicular to bullet path
– Rapid compression, crushes and tears tissue
•  Cavity forms behind bullet pulling in debris with suction.

Question 24

Damage Pathway

Answer 24

•  Direct Injury
– Damage done as the projectile strikes tissue
•  Pressure Shock Wave
– Human tissue is semi­‐fluid
– Solid and dense organs are damaged greatly

Question 25

Damage Pathway

Answer 25

``` •  Temporary Cavity – Due to cavitation •  Permanent Cavity – Due to seriously damaged tissue •  Zone of Injury – Area that extends beyond the area of permanent injury ```

Question 26

Low-­Velocity Wounds (Objects)

Answer 26

– Knives, Ice-­picks, Arrows – Flying objects or debris – Slow speed limits kinetic energy exchange as the object enters the body

Question 27

Low velocity wounds (Injury limited to tissue impacted)

Answer 27

– Object pathway – Object may be twisted or moved – May be inserted at an oblique angle

Question 28

Human Characteristics (Male Attacker)

Answer 28

– Most ojen strike with forward, outward or crosswise stroke

Question 29

Human characteristics (Female Attacker)

Answer 29

Strike with an overhand, downward stroke

Question 30

Human Characteristics (Victim)

Answer 30

–  Initially aiempt to sheild themselves with their arms | – Often receive upper extremity lacerations (defensive wounds)

Question 31

Injuries to Tissue and Organs

Answer 31

•  Extent of damage varies by the particular type of tissue that a projectile encounters •  Density of tissue affects the efficiency of energy transmission •  Resiliency: – Strength and elasticity of an object

Question 32

Connective tissue

Answer 32

•  Dense, elastic and held together very well •  Limited tissue damage – Characteristically absorbs energy – Wound track closes quickly due to resilience, limiting prijectile’s pathway

Question 33

Solid Organs

Answer 33

–  Have density but not resiliency –  Tissues compress and stretch in relation to cavittional wave –  Hemorrhage tends to be severe

Question 34

Hollow Organs

Answer 34

–  Filled with noncompressable fluid that rapidly transmits energy –  Energy can tear organ apart explosively –  Slower, smaller projectiles may produce small holes and create slow leaks

Question 35

Lungs

Answer 35

*   Air in lung absorbs energy *   Parenchyma is compressed and rebounds *   Injury less extensive than with other tissue *   Significant disruption of chest wall integrity may result in pneumothorax or hemothorax

Question 36

Bone

Answer 36

*   Densest, most rigid and nonelastic body tissue *   Resists displacement until it fractures often into numerous pieces *   Significantly alter projectile’s path through the body

Question 37

General Body Regions (Extremities)

Answer 37

–  Injury limited to resiliency of tissue | – 60-­80% of injuries with

Question 38

General Body Regions Abdomen (Includes Pelvis)

Answer 38

– Highly susceptible to injury and life-­threatening hemorrhage – May perforate bowel resulting in irritation and infection

Question 39

General Body Region Thorax

Answer 39

– Rib impact results in explosive energy – Heart & great vessels have extensive damage due to lack of fluid compression – Any large chest wound compromises breathing

Question 40

General Body Region Neck

Answer 40

– Traversed by several critical structures – Penetrating trauma likely to damage vital structures: •  Airway compromise •  Heomrrhage •  Neurological deficits – Associated swelling and hematoma may lead to similar complications

Question 41

General Body Region Head

Answer 41

– Skull is a hollow strong and rigid container – Brain is a delicate semisolid organ very susceptible to injury –  If bullet penetrates the skull, cavitational energy trapped, damage extensive – Suicide attempt often result in facial trauma as a result of weapon recoil

Question 42

Entrance wound

Answer 42

•  Size of bullet profile for non-­deforming bullets •  Deforming projectiles may cause large wounds •  Close Range – Powder Burns (tattoing of powder) – 1-­2 mm circle of discoloration –  Localized subcutaneous emphysema

Question 43

Exit Wounds

Answer 43

``` •  Caused by the physical damage – Passage of bullet – Cavitational wave •  Blown outward appearance •  May more accurately reflect damage caused by bullet ```

Question 44

Scene Assessment

Answer 44

•  Ensure that police have secured the scene before you enter it – Potential for violence •  Consider the possibility – Additional assailants – Victim may be armed •  Preserve crime scenes as much as possible – Cut around bullet or knife holes and preserve clothing as evidence

Question 45

Penetrating Wound Assessment

Answer 45

•  Determine pathway of object – Projectiles do not always travel in straight lines –  Look for entrance and exit wounds •  Anticipate potential organ injury •  Bullet wounds to head, chest or abdomen – Rapid transport – Treat aggressively for shock

Question 46

Facial Wounds

Answer 46

•  Gunshot wounds may destroy airway landmarks •  May have to consider more invasive procedures – Cricothyrotomy – Cricothyrostomy

Question 47

Chest Wounds

Answer 47

•  Chest wall is thick and resilient •  Requires a large wound to create opening for air movement – Smaller wounds usually result in no air movement •  May have to utilize: – Three sided dressing or chest seal – Needle decompression •  Consider the possibility of trauma to the heart and great vessels

Question 48

Impaled Objects

Answer 48

•  Mainly a low velocity wound, dangerous to remove – May cause more damage on exit – May be restricting blood loss •  Immobilize as the object is found •  Objects to be removed –  Lodged in cheek or trachea that interfere with airway –  Interfering with CPR

Question 49

Different projectiles of different weights traveling at different speeds cause:

Answer 49

``` –  Low Energy/Low Velocity •  Knives and arrows – Medium Energy/Medium Velocity Weapons •  Handguns, shotguns, low-­powered rifles •  250-­400 mps – High Energy/High Velocity •  Assault Rifles •  600-­1,000 mps ```