5. Introduction to
Penetrating Trauma
There are 30,000 deaths in the U.S. annually due to
shootings.
Other mechanisms of penetrating trauma include:
Knives, arrows, nails, etc.
Understanding the principles of energy exchange
increases the index of suspicion associated with the
MOI.
7. Kinetics of Penetrating Trauma
When a projectile strikes a target, it exchanges its
kinetic energy with the object struck.
An object’s kinetic energy is equal to its mass times
the square of its velocity, all divided by 2.
8. Kinetics of Penetrating
Trauma
The greater the mass of an object, the greater its
energy.
If you double the mass of an object, it will have twice
the kinetic energy.
The speed (or velocity) of an object has a squared
relationship to its kinetic energy.
If you double the speed of an object, its kinetic energy
increases by fourfold.
9. Ballistics
Study of the characteristics of projectiles in motion
and effects upon objects impacted
Factors affecting energy exchange between a
projectile and body tissue:
Velocity
Profile
Stability
Expansion and fragmentation
Secondary Impacts
Shape
11. Ballistics
Profile
Portion of bullet you
see as it travels toward
you
Larger profile = greater
energy exchange
Caliber
Diameter of a bullet (ID
of gun)
0.22 caliber = 0.22 inches
Bullets become
unstable as they pass
from one medium to
another.
Collection of Robert Porter
12. Ballistics
Stability
Bullet length increases bullet tumbling
Can reduce the accuracy of the shot
Reduced by rifling in barrel (spinning)
Yaw
Gyroscopic effect on the center axis of the bullet
that reduces tumbling
Tumbling of bullet once it strikes object
Increases rate of energy exchange
Greater tissue damage
14. Ballistics
Secondary Impacts
Bullet striking other objects can cause yaw and tumble
Body armor (Kevlar)
Transmits energy throughout entire vest resulting in blunt
trauma
Myocardial contusion
Pulmonary contusion
Rib fractures
15. Ballistics
Shape
Handgun ammunition is rather blunt
More resistant to travel through human tissue
Releases kinetic energy more quickly
Rifle bullets are more pointed and cut through the
tissue more efficiently
May tumble or fragment
16.
17. Specific Weapon
Characteristics
Handguns
Often a small-caliber,
short-barreled,
medium-velocity
weapon
Severity of injury is
related to the organs
directly damaged by
the bullet’s passage
Collection of Robert Porter
22. Specific Weapon
Characteristics
Shotgun
May fire a single
projectile (a slug) or
numerous spheres
(pellets or shot) at
medium velocity
The larger the shot,
the smaller the
number of projectiles
25. Specific Weapon
Characteristics
Knives and Arrows
Slow-moving, penetrating objects cause low-velocity,
low-energy wounds
Usually limited to physical injury caused by direct contact
between the blade or object and the victim’s tissue
Hunting tips designed for arrows can be especially
damaging
26. Biomechanics of
Penetrating Trauma
Direct Injury
Occurs as the projectile strikes tissue, contuses and
tears that tissue, and displaces the tissue
Limited to the profile of the bullet as it moves through
the body
Handgun bullet damage is usually limited to direct
injury
27. Biomechanics of
Penetrating Trauma
Pressure Shock Wave
When a high-velocity high-
energy projectile strikes
human tissue, it creates a
pressure shock wave.
The faster and more blunt
the bullet, the greater the
effect.
28. Biomechanics of
Penetrating Trauma
Temporary Cavity
Space created behind the high-energy bullet as tissue
moves rapidly away from the bullet’s path
After the bullet’s passage, tissue elasticity causes the
temporary cavity to close
Cavitation
29. Biomechanics of
Penetrating Trauma
Permanent Cavity
Tissue may not return to its normal orientation,
resulting in a permanent cavity
Cavity fills with debris
Zone of Injury
Zone of injury extends beyond the permanent cavity
May be slow to heal
33. Specific Tissue/Organ
Injuries
Connective Tissue
Absorbs energy and limits tissue damage
Organs
Solid organs
Dense and low resilience
Hemorrhage associated with solid organ projectile
damage is often severe
Hollow organs
Fluid filled: transmit energy = increased damage
Air filled: absorb energy = less damage
34. Connective Tissue
Including muscles and skin
Dense, elastic, hold together well
‘Absorb energy while limiting tissue damage’
Damage is limited to projectile’s pathway
35. Solid Organs
Liver, spleen, kidneys, pancreas, brain
Have density but not resiliency
Hemorrhage is often severe
Damage outside of the profile
36. Hollow Organs
Bowel, stomach, heart, bladder
Muscular and hold fluid
If filled with fluid, organ may tear explosively
If filled with air (not distended), injury tolerated
Pericardial tamponade
37. Specific Tissue/Organ
Injuries
Lungs
Air in lung absorbs energy
Parenchyma is compressed and rebounds
Pneumothorax or hemothorax can result
Bone
Resists displacement until it shatters
Alters projectile path
38. General Body Regions
Extremities
Injury limited to resiliency of tissue
60–80% of injuries with <10% mortality
Do not immediately threaten life
Injuries above the elbow or knee are more likely to
cause significant vascular injury
Abdomen (includes pelvis)
Highly susceptible to injury and hemorrhage
Bowel perforation: 12–24 hrs. peritoneal irritation
39. General Body Regions
Thorax
Rib impact results in
explosive energy.
Heart and great
vessels have
extensive damage
due to lack of fluid
compression.
Any large chest
wound compromises
breathing.
40. General Body Regions
Neck
Damages trachea and blood vessels
Neurological problems
Sucking neck wound
Head
Cavitational energy trapped inside skull
Serious bleeding, lethal
45. Special Concerns With
Penetrating Trauma
Penetrating Wound Assessment
Try to determine the pathway of the penetrating
object
Internal organ injury potential
Entrance and exit wounds
46. Special Concerns With
Penetrating Trauma
Penetrating Wound
Care
Facial wounds
Facial gunshot
wounds destroy
many airway
landmarks
Cricothyrotomy may
provide temporary
airway care
Collection of Robert Porter
47. Special Concerns With
Penetrating Trauma
Penetrating Wound Care
Chest wounds
Requires a large wound to be present for air to
move into the chest cavity
Open pnuemothorax
Tension pnuemothorax
Consider the possibility of heart and great vessel
damage
Pericardial tamponade
48. Special Concerns With
Penetrating Trauma
Impaled Objects
Low energy
Dangerous to remove
Do not remove unless:
In cheek, neck, or trachea
Interferes with CPR
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55.
56. Summary
Introduction to Penetrating Trauma
Kinetics of Penetrating Trauma
Specific Tissue/Organ Injuries
Special Concerns with Penetrating Trauma
