Forensics Flashcards
Three types of modes of death
- natural
- unnatural (accidental, suicidal, homicidal)
- unknown
What deaths are reportable to the coroner or ME
- unexpected
- suicide
- accidental
- while in custody
- self-abortion
- etoh intoxication
- Not: dies under provider’s care, knew sick, know likely to die
Rigor Mortis and body temps
- occurs at 3 hours
- 4 hours: extremities still warm
- 6 hours: trunks still warm
- Lose about 1.5 degree body temp F per hour dead
Dependent lividity
- Occurs where blood pools after heart stops beating
- Red where blood pools, white where body was bearing weight
- Allows understanding of body position after death
- Also, if see during resuscitation, sign person will not recover…
What animal eats in a linear, buffet fashion?
rats
What to think when see abrasion, damage to neck on dead person?
- could be pre-death injury
- Could also be a post-mortem finding, skin becomes very fragile and tears easily, could be due to rough handling by EMS, funeral home, etc.
How does tension pneumo kill?
Pushes mediastinum away from injured side, can squish vena cava, kinks it like a hose = no blood to heart. Tx will quickly resolve!
What to consider if pt has road rash
If not removed in 24 hours becomes a perm tattoo
Signs of basilar skull fx
- battle sign (behind ear)
- raccoon eyes
- CSF otorrhea and CSF rhinorrhea
- TM perf
- Hemotympanum
What is a pattern contusion
bruise that shows what was used to cause injury: pool stick injury
How to differentiate injury dt fall vs. fight?
- Fall injuries will occur on the “parts that stick out” on the face
- Fight can occur in recessed areas like eye socket.
Laceration definition and how to differentiate from cut
- blunt trauma
- skin stretches until it rips in a jagged fashion
- will contain bridging tissue (area that survived trauma)
- will contain abrasion around the wound
- Cuts will be straight, no surrounding abrasion
Child abuse
- bruising on face, abdomen, thighs, hips
- Lacerations on lips (scalloped edge if not repaired)
- Flagellation marks from whipping
- Cigarette burns: round
- Cephalohematoma: grab by hair and pull
excuse me while I vomit
MVA
- Extent of accident does not always equal extent of bodily injury
- Ask: where in car, seat belt worn? Will help determine MOI
- Chevron marks: tire ran them over
Auto-Pedestrian accidents
- can sometimes tell how person was standing when hit:
- bilateral injury at same level indicates standing still
- bilateral injuries at different levels indicates moving
- Check wounds for paint fragments
- Look at the car
IV drug use tid-bits
- Smoke, soot, etc. on needle is cause of peri-venous fibrosis (hypo pigmentation)
- Bent needle = easier access
- Bulb syringe: use to get all drug by washing out
- Skin popping: SQ injection vs. IV. Lesion called “rosette”. Can get infected and ulcerate
- Frothy edema
- Tattoos: Charlie Chaplin/King Herald = heroin, can be used to hide tracks, roadmap to veins
Hangings
- leave a looped mark, not a straight line
- If hang long enough will get petechia in leg called tardieu sign, turn into purpura
- Don’t forget about autoerotica… Family might try to cover it up
Signs of smothered with a pillow
White around lips, nose, chin
Knife injuries
- Dull: black collar abrasions (dt friction)
- Single edged: sharp on one side of the cut, dull on the other
- Figure 8 and dull: scissors
- Hands: usually sign of defense
- Prod marks: poke marks near injury
- Vital erythema (cut when alive, red and blood) vs. no blood (cut when dead and not bleeding)
What should you try to do when cutting off clothing and treating patient
- try to not damage evidence (cut through GSW hole)
- look for evidence like paint, keep if you can
GSW
- how to tell if from distance or close
- close will have soot, gunpowder, etc. on skin
- Far will just be damage from bullet
GSW
- enter vs. exit
Entrance hole - will be smaller than bullet (stretches skin as enters) - Collar abrasion - Bone spicules travel same direction as bullet Exit - bigger hole bc now bullet tumbling - no soot, etc. - stellate dt tumble
*** NEVER name entrance or exit, just number wounds 1, 2, etc.
What finding can be found if a revolver is used?
cylinder gap
- if cheap gun, some material will come out gap and cause secondary injury next to bullet hole
Higher power guns
- more injury
- exit wound bigger than with handgun
