Projectile Trauma - Lecture 20 Flashcards
What is Projectile Trauma?
- bullets
- anything projected by an explosion
- high velocity trauma
What are the 3 basic types of firearms?
- handgun
- rifle
- shotgun
What are the 3 characteristics that determine the projectile’s effect on bone?
- Size
- projectile diameter or barrel size (for shotgun) - Construction
- profile, internal composition, and covering (jacketing) - Velocity
- projectile speed
- can indicate what kind of gun was used
What is caliber? How is it measured?
- size of the single bullet
- reported in 1/100 of an inch or in mm
What is the gauge? How is it measured?
- size of shotgun pellets
- measured in a fraction of a pound
What are the three different sizes of bullets?
- target shot
- small - Bird shot
- small shot size
- more pellets in cartridge - Buck shot
- large shot size
- lets pellets in cartridge
What are the 3 different types of bullet construction?
- sharp
- designed for rifles and to enter and exit the body - blunt
- meant to deform in body and stay imbedded - hollow-point
- maximize damage
- point will split into quarters
What are the two types of internal composition?
- lead
- for blunt bullets
- typical bullet construction - exploding
What are the 3 types of jacketing?
- full-metal jacket
- fully encased in copper and allows bullet to pass through body - semijacket
- base encased in copper so tip deforms
- possibly stays in body - nonjacketed
- significantly deform and will stay in body
The increase in projectile velocity means the size of the ____ needs to be increased.
barrel
What is rifling and why is it important?
- a series of raised and receding edges (lands and grooves) in the barrel of a gun
- these send the bullet spinning which allows the bullet to maintain its trajectory over long distances
- leaves a unique pattern on the casing that can be traced back to the gun
What is tumbling?
- after 1000 yards the rifle bullet will lose its velocity and trajectory and go off course
- will leave a specific mark on the bone
Why is the exit wound larger than the entry wound?
- because the bullet is likely deforming in the skull
- because the bullet is slowing down and could make the bullet tumble
Should the entrance wound match closely to the caliber of the bullet?
yes
What do radiating fracture lines from the entry wound indicate?
bullet was travelling at a high velocity
What does a round wound shape indicate?
the bullet is entering the skull at a 90 degree angle and are perpendicular to the surface
How can an entry wound on a suture effect the estimation of the caliber of the bullet?
- small pieces of the sutures will fall out
What does an oval shape exit wound indicate?
- normal exit wound
- bullet tumbled within skull and is no longer perpendicular
What is a keyhole fracture/wound?
- both inward and outward bevelling
- bullet travelling at a severe angle to the skull
- an entrance and exit wound
What does an irregular shaped bullet wound indicate?
- a possible exploding component to the bullet
- ## or a hollow point bullet
If a bullet caliber is larger does that mean the bullet wound will be larger?
yes
How can radiating fractures from multiple bullet wounds indicate the sequence of events?
same way as BFT
How are concentric fractures caused by bullets?
- high velocity
- bullet is creating waves in the brain which create the fracture lines
What kinds of fractures can bullets cause in long bones?
- butterfly fractures
- irregular fractures (comminuted fracture that is caused by shotgun)
