Forensics Flashcards
a. Rigor Mortis
b. Algor mortis
c. livor mortis
a. body becomes stiff over time; max b/t 24-48 hrs, and then goes away
b. body cools after death; varies dependent on outside temperature
c. no systemic circulation, so blood pools at dependent portions of the body; become fixed (fixed libor) after a few hours (you can’t determine a specific time)
a. putrefactive
b. adipocere formation
c. mummification
a. most common type; lipid latent fluids accumulate in body cavities, skin changes colors and slips; biggest load of bacteria is over the cecum as they can get through the bowel wall, and infect skin over cecum
b. body found in water; epidermis is dissolved; lipid layer encases the body (fresh>salt water)
c. rarer; bodies that die in the dessert/places with little moisture, they can dry up
what questions does a ME answer?
- How did they die? (ex. hemorrhage)
- Manner of their death? (ex. homicide)
- Why did they die? (ex. gun shot)
Long list of types of injuries
Mechanical Force – Abrasions – Lacerations – Contusions – Incise wounds – Gunshot wounds – Blast injury Thermal injuries – Burns – Hyperthermia • Heat cramps • Heat exhaustion • Heat stroke – Hypothermia Ionizing Radiation Electrical injuries – Variables – Low intensity – High intensity Atmospheric pressure – Decompression (p 128R)
When do we get for sure death from radiation?
10-20SV or >50 SV
small bowel; brain
What are the three blunt force injuries?
a. lacerations
b. abrasion
c. contusion
What is the wounding formula?
W = E x 1/T x 1/A x K
K = modifying factors (elasticity of the striking object or the tissue being injured etc) E = Energy transferred = 1⁄2 MV2 T = Period of energy transfer (time) A = Area of application of force
contusion
- Definition: “A contusion is a bruise and results from hemorrhage into soft tissue due to rupture of subcutaneous blood vessels by blunt force injury.”
- Note: The epidermis in a contusion is intact and hence a contusion does not bleed externally. A contusion may be seen upon the skin or within deep viscera (internal organs, such as heart, lungs, brain, etc.)
What does the extent/severity of a contusion depend on?
a. Amount of force applied
b. Vascularity of tissue injured
c. Type of tissue injured: areolar (loose or thin) tissue such as the eyelids - tends to bleed more
d. Location of the tissue: tissue overlying hard bony structures is more easily bruised
e. Easy bruisability: advanced age, cirrhosis of the liver, coagulopathies, etc.
Yellow means
18 hours or older bruise
Abrasion
- Definition: “An abrasion is a wound in which (primarily) the epidermis is injured. It is produced by friction scraping away epidermis or crushing of the epidermis by direct pressure or a blow tangential to the surface”.
- Note: An abrasion oozes serum or blood (but does not tend to bleed profusely) and generally heals by formation of a scab
type of abrasions
a. Brush (or scrape or gliding) abrasion
b. Impact abrasion:
c. Patterned abrasion: Occurs when the abrasion recapitulates the surface appearance of the instrument
Stab wound
Definition: “A stab wound is a sharp force injury in which the depth of the wound track is greater than the length of the wound on the skin (deeper than longer). It is produced when an instrument with a pointed edge is thrust into the body or the body falls on the pointed edge”.
What is most important in gun wound damage?
velocity > mass
low velocity: small entry, no exit
high velocity: reality small entry, big exit
Ranges of gunshot wounds
- Contact range: marginal abrasion; soot/powder in depths of wound
- Intermediate range: marginal abrasion, powder tattooing/stippling around wound
- Distant range: marginal abrasion, no powder tattooing/stippling, no soot/powder in the depths of a wound
