Projectile / Stab Flashcards
What is the Equation of Kenetic energy of a projectile?
- KE = ½ x MASS x VELOCITY x VELOCITY
What influence does the size and shape of a projectile have?
- How the object behaves in contact with tissue and in turn how much kinetic energy is given up.
What factor of tissue can influence the amount of energy it can absorb?
- How elastic the tissue is.
What else may influence the amount of energy absorbed?
- Ballistic protection/body armour
What are the two types of gunshot wound GSW?
- Penetrating
o Where the bullet penetrates and becomes lodged in the body - Perforating
o Where the bullet penetrates all the way through the body and exits out at some point
What type of wound will be seen in a Handgun?
- Small entry wound
- Lethal range – 200m
What type of wound will be seen in a shotgun?
- Multiple entry wounds
- Leathal range 50-100m
What type of wound will be seen in a Rifle?
- Small entry wound with either large cavernous exit wound or multiple exit wounds from fragmentation
- Lethal range 1-4km
What types of bullets are in use for Rifles/Handguns?
- Full metal jacket – metal casing around a soft core
- Soft point – bullet has exposed tip and rapidly expands
- Hollow point – expanding bullet that can break up within the body
What types of shotgun shells are there?
- Birdshot – small pellets
- Buckshot
- Slugs
What type of shotgun gauges are there?
- Gauge refers to the diameter of the barrel
- 12 gauge has a diameter of 18.5 mm
- 20 gauge has a diameter of 15.6 mm
What is the energy within a projectile dependent upon?
- Velocity
- Weight
- Distance
- Deformation
- Fragmentation
- Type of tissue struck
What feet/sec is considered low velocity?
- <2000 feet/sec (600m/s)
What feet/sec is considered high velocity?
- > 2000 feet/sec
What pathology considerations need to be made in regards to ballistics?
- Can injure hard and soft tissue
- One projectile can cause multi-system trauma
- Be aware of entry and exit wounds, but remember that projectile doesn’t always have to travel in a straight line.
- Foreign material in the wound
- Thermal injuries
What are severities of ballistic injuries dependent on?
- Penetration
- Cavitation
- Fragmentation
What is entrance wound contact range?
- Is seen when a gun is held up against the skin surface
- Results in searing edges of wound, secondary to flame/hot gasses emanating from the gun
- Will be a hard contact wound
- Gas may enter into the tissue
What will entrance wound of intermediate range present as?
- Tattooing on skin
o Fragments of burning and non-burned gun powder penetrating the skin - Stippling
o Fragments abrade the skin but do not penetrate
What will an entrance wound look like with intermediate range?
- NO gunpowder burns only bullet wound site.
List some knowledge about exit wounds.
- Size does not usually correlate with calibre used
o Speed is the most important factor - Irregular wound would suggest – small highly deformed bullet at high speed
- Large, formed bullet would create a regular wound
What is the primary damaged caused in GSW?
- Crushing and laceration of the tissue as the bullet impacts and pushes its way through.
- Orangs may become perforated
- Permanent cavity or tunnel is created
What is secondary damaged caused in GSW?
- Temporary cavities created due to the shockwaves that exerted outwards from the bullet trajectory.
- Causes a radical stretch injury
- Creates a vacuum that sucks in hot gases and debris causing internal burns and sepsis.
- The cavity can be 40x > diameter than the bullet depending on velocity
- Shockwaves can be as much as 200mmhg.
What occurs in tertiary damage in a GSW?
- Multiple fragments created by impacting and shattering bone
What does the THREAT acronym stand for?
- T – Threat suppression
- H – Haemorrhage control
- R – Rapid extrication to safety
- A – Assessment by medical providers
- T – Transport to definitive care
What Hx taking should be taken at shootings?
- How many gun shots?
- How many times do you think you were shot?
- What position were you shot in?
- How far were you from the barrel end?
- Type of bullet
- Calibre/gauge of bullet/shell
- Last tetanus?
What should be the focus on a stab wound when undertaking assessments?
- Situation
- Size
- Appearance
- Orientation
- Direction of infliction
- VSS
