Forensic Medicine Flashcards
what is the major focus of a forensic investigation
why did someone die? cause of death how did they die? mechanism what is the manner of death (NASHU) Natural Accident Suicide Homicide Undetermined
who can legally certify and sign a death certificate?
physician can only sign if the death was natural
all others are medical examiners -accident suicide homicide undetermined
major misconceptions
time of death
- not something that can be established in a limited time frame
- rigor mortis- reaches peak at room temp at 24 hours
rapidity of testing
-diagnostic tests take longer times
The focus of a forensic examination/inquiry is not natural death (other than to rule out/discern evidence for, or consider circumstances which may be indicative of foul play)
medical examiners have no duty to the family but to the state
if a family is exceptionally against an autopsy, then be suspicious b/c family members are more likely to be involved in the crime
family can be a problem
why are there so few autopsies done at hospitals
b/c of lawsuits
so they are performed at ME offices –> but the focus is never on natural death
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 = ½ MV^2
T = Period of energy transfer (time)
A = Area of application of force
inversely related to time and area
the more young men b/w 15-34, the more violent the crime
testosterone makes you crazy
physical environment injuries
mechanical force
- laceration is ALWAYs due to blunt force injury, split of tissue
- abrasion
- contusions
- incise wounds
- gunshot wounds
thermal injuries
- burns
- hypothermia
- hyperthermia
ionizing radiation
-leukemia and lymphomas initated
electrical injuries
atmospheric pressure
- blast injury
- decompression
cause of death versus mechanism of death
mechanism:
shock
cardiac arrhythmia/arrest
septic shock
cause of death:
AIDS
manner of death examples
natural accident suicide homicide undetermined
three typical wounds produced by blunt force trauma
abrasion
contusion
laceration
laceration
soft tissue bridging
depths
contusion
extent and severity depends on
amount of force
vascularity of tissue injuried
type of tissue (areolar tissue such as eyelids, bleeds more)
location of the tissue–>
tissue over bones is more easily bruised
easily bruisability - advanced age, cirrhosis, coagulopathies
contusions and color?
yellow
blue, purple
brown
yellow- most significant color and its presence indicates that the bruise is at 18 hours or older
blue, purple and red do NOT assist in dating bruises
brown is a mixture of colors and therefore is not useful
abrasion
epidermis is injured by friction/scraping or crushing
oozes serum or blood, but does not bleed profusely
torsional marks
rolled edges of skin tell directionality
3 types of abrasions
brush- grazing or sliding motion.
impact
patterned- recapitulates the surface appearance of the instrument
passenger windows cause dicing injuries
wheres windshield glass causes other marks
stab wound
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)
single blade edge
sort of triangle with one edge that isn’t “sliced” like the other edges
gun shot wound against skin
close range 1-2 inches
marginal abrasion
stippling deposited (debris) = intermediate gunshot wound
medical examiners can measure what the range/distance from skin was
wad inside a shotgun shell - shows up as a small round circle
pellets
shotgun wound on the head
the adult skull has an inner outer table separated by the diploe
in entry wound the outer table of the skull is typically sharply circumscribed and the inner table is beveled
fracture emanating from blunt force or in some cases gunshot wounds, do not ramify across previous fracture lines (don’t cross)
mass disasters approach
macro level: the scene
- safeguarding- live people first
- surveying
- documenting
- proper approach to specimen retrieval
Micro level:
biologic materials retrieval and transmittal vs. inorganic specimens/substances
37 year old male uresponsive no singinficant PMH diuretic for high blood pressure 50 lb overweight smoker hasn't seen physician in 3 years trauma to his face
looks like shit - looks like there are bumps/bruises and abrasions on the body that are consistent with a fall/trauma
what is the plan of action…
he does have an elevated serum glucose
what is the most likely cause, mechanism and manner of death?
send the body to the ME b/c it looks like there is trauma to the body
he is not being followed by a physician and doesn’t really have a diagnosis
he does have risk factors for sudden cardiac arrest:
high blood pressure
obese
smoker
he has lacerations/abrasions over the bony prominences and no other types of trauma
atherosclerotic cardiovascular disease natural death
patient drinking bac of .2 black out and head hurts laceration on the back of his head being annoying
laceration on the back of his head
based on the appearance of the wound (scalp lac) you conclude…
the lesion is NOT a sharp force injury. He likely fell due to inebriation
the injury is due to blunt force (could be the ground)
soft tissue bridges*** true laceration due to blunt force trauma, may bleed significantly
marginal abrasion
unless it is a very severe injury, the patient doesn’t necessarily need MRI/CT
patient with gunshot wounds of his chest two entries on the left and single exit on the right
bilateral hemothorax
the exit is much larger than the entry, what does this imply…
he also shows powder stippling of the shoulder what does this imply…
the feature imply a homicide attempt
exit wound–> this implies high velocity–> much more related to the speed of the projectile than the mass
stippling means it was an intermediate gunshot wound and most likely NOT self inflicted
