Forensics - Physical Injury Flashcards
Abrasions
Damage to epidermis - “scrapes”
- Greater or lesser hemorrhage beneath
Abrasions are caused by?
Tangential blunt force
Contusions
Intact skin with hemorrhage in dermis below - “bruise”
Contusions are caused by?
Blunt force
Contusions tend to change colors as healing progresses. What is signified if the contusion is yellow?
Older than 18 hours
Are all bruises considered contusions?
NO - contusions are solely from blunt force trauma
Lacerations
Splitting of skin with hemorrhagic bridges in depths
- Wider than they are deep!
Lacerations are caused by?
Blunt force that overcomes tensile properties of skin
Incise wounds
Splitting of skin WITHOUT bridges in depths
- Deeper than they are wide!
Incise wounds are caused by?
Sharp objects - knives, razors, etc.
What are examples of chronic disorders than can cause more severe bleeding at wound sites?
- Renal disease (due to HTN and diabetes)
- Liver disease (due to alcohol abuse)
- Autoimmune, coagulation or neoplastic disorders
With blunt force trauma, the risk for what increases?
Intracranial hemorrhage and bleeding into organs and body cavities
With blunt force trauma, the risk for intracranial hemorrhage and bleeding organs increases for what population?
Elderly
When drug abuse is added to a case, why is that viewed as problematic in court?
Adds ambiguity
GSW
Gunshot Wound
What are GSWs characterized by?
Marginal Abrasion
Types of Handguns?
Revolver
Semiautomatic
Handguns are ____ velocity weapons
LOW
What type of bullets do handguns use?
Small caliber bullets such as hollow point round
Describe what happens when small caliber bullets used by handguns meet tissue
Slow with tumbling
= Deformed bullet remains in the individual causes more tissue damage!
Why do handguns cause lots of tissue damage?
Due to the deformed bullets remaining inside the individual
Many handguns and long guns have rifling. What is that?
Grooves cut into barrel of gun that add accuracy and impart grooves on bullets
What does rifling allow for?
To match the bullet to the gun
What is a type of gun that shoots handgun ammunition?
Machine pistols (uzi-type)
Civilian versions of machine pistols are?
Semiautomatic
Police versions of machine pistols are?
Automatic
Types of Long guns?
Rifles
- Magazines
- Bolt action
Long guns (rifles) are ____ velocity weapons
HIGH
Long guns shoot what type of bullets?
Fully jacketed
With long guns, the exit site is what compared to handguns?
Larger and more stellate
Types of Shotguns?
Smoothbore
What are shotguns loaded with?
Shells that contain pellets of varying size (gauge)
What controls the spray of pellets from a shotgun?
Choke structure
Lesser choke on a shotgun results in?
GREATER dispersion of shot mass
Too short of a choke on a shotgun is?
Illegal riot gun
- due to wide dispersion at a short range
What else can be loaded into shotguns that cause devastating short range injuries?
Slugs
Range refers to?
Distance from end of gun barrel to entry wound on individual
What is seen with a contact or close range GSW?
- Soot and gunpowder in depths of wound
- Muzzle or sight burn stigmata
What is seen with an intermediate range GSW?
Dirt, soot, gunpowder embed in the skin
“powder tattooing or stippling”
Dirt, soot, gunpowder embedded in the skin with intermediate range GSWs
What is seen with a distant range GSW?
NO soot, dirt or particles at wound site!!
Describe the layers of the adult skull affected by a GSW
Outer table
Diploe (spongy bone/cancellous bone)
Inner table
Entry site for a bullet to the head is characterized by?
Outer table circumscribed
Inner table beveled
Exit site for a bullet to the head is characterized by?
Inner table circumscribed
Outer table beveled
As a projectile encounters tissue is slows down. What does this cause?
Mass transfers energy to substrate
If the tissue is beveled, it received?
More energy transfer
What allows medical examiners to discern between the entry and exits GSWs to the head?
Circumscription and beveling
