chapter 4 Flashcards
what’s the most important piece of evidence in a case involving death?
victim
what 3 jobs are involved in performing an autopsy/determining death situations
pathologist
anthropologist
entomologist
forensic pathologist duties
investigate the cause, manner, and time of death
conduct autopsies
who does most of the cutting/weighing of organs in an autopsy?
assistant
2 types of forensic pathologists
coroner
medical examiner
what’s the difference between a coroner and a medical examiner?
coroner: elected
medical examiner: have medical degrees, appointed to their position
critical phase of scene investigation
preliminary reconstruction of events that preceded the onset of death
autopsy definition
medical dissection and examination of a body post-mortem
when are autopsies performed
unexpected/unnatural deaths or by request of the family
forensic autopsy is performed by a
medical examiner
forensic autopsy purpose
to aid in criminal investigation
do forensic autopsies require family consent?
no
when are forensic autopsies performed
sudden, violent, unexplained deaths
who are medical autopsies performed by
medical examiners
medical autopsies purpose
determines extent of disease or effects of therapy (if applicable)
looks for undiagnosed disease
do medical autopsies require family consent
yes
what percentage of deaths get a medical autopsy?
less than 12%
external autopsy
overview of body condition
classifies injuries (blunt force trauma, ligature marks)
internal autopsy
y-shaped incision starting at shoulders to pubic bone
takes samples to send to tox
manner of death
relates to circumstances that led to death
culmination of complete investigation
determines cause of death
5 categories of manner of death
natural causes
homicide
suicide
accidental
undetermined
is the manner or cause of death reported on the death certificate?
manner
cause of death
reason a person died (blunt force trauma, sharp force injuries, asphyxia)
blunt force trauma
caused by non-sharp injuries
sharp force injuries
injuries from weapons with sharp edges
asphyxia
anything that interferes with Oxygen intake
rigor mortis
stiffening of muscles after death
what muscles does rigor mortis affect first?
small muscles
rigor mortis max stiffness
12-24 hrs post mortem
how long are joints stiff? what happens after
1-3 days post mortem
releases ions
what is rigor mortis affected by?
temp, weight, activity level
autolysis
breaking down of cells
how do muscles contract?
myosin and actin lock in the help of calcium
muscles remain contracted until ATP (which requires oxygen to be made) attaches to myosin
ATP pumps calcium out of cell
how do muscles start to break down after death?
when enzymes leak out
why do muscles stay contracted after death?
when there is no ATP at death
livor mortis
settling of blood in areas of the body closest to the ground
what force allows livor mortis to happen
gravity
when does livor mortis start
20-30 min post mortem
when does the color from livor mortis fully develop
12 hrs after death
when does the color from livor mortis go away
never
what does livor mortis determine
position of victim when they died
algor mortis
cooling of body after death
when will the body stop cooling after death?
when it reaches room temp
when does algor mortis begin
about 1 hour after death
formula for determining time of death
1st 12 hours: (98.6 - (body temp))/1.4
after 12 hours: (98.6 - (body temp) -16.8)/.7
add 12 to the answer to get total number of hours
where is body temperature obtained from after death?
rectum or liver
outside factors that can influence algor mortis
weather/temp
location
size of body
clothing
vitreous humor
fluid behind eye
do potassium levels increase or decrease after death?
increase
what is the purpose of using fluid from the vitreous humor to determine time of death?
fluid is less susceptible to contamination because it is secluded from other parts of the body
why are stomach contents analyzed in an autopsy?
food breaks down at a predictable rate
how long can human remains last?
decades
how is gender determined in an autopsy?
size and shape of skull and pelvis
what can bone remains determine?
gender
age
race
height
physical injuries (sometimes)
forensic anthropologist
identifies and examines human skeletal remains
what happens when bones are found?
treated as a crime scene
secured and thoroughly searched
locate all scattered bones
identify footwear impressions or discarded items
all evidence is documented and collected
bone characteristics
cartilage before bone
osteoblasts deposit materials or minerals into center of cartilage and harden it
bones constantly produced and broken down
how many bones to babies have
450
how many bones do adults have? how
206, they fuse
bones get _ and _ with age and use
longer, thicker
when do you stop growing?
when cartilage growth plate fuses
male pelvic characteristics
narrow pelvic opening
small pelvic outlet
long, narrow, forward sacrum
close ilia
V-shaped
subpubic angle: less than 90
female pelvic characteristics
wide, circular pelvic opening
large pelvic outlet
short, wide, backward sacrum
spread ilia
U-shaped
subpubic angle: greater than 90
male skull characteristics
large
mandible at right angle
large mastoid process
pronounced brow bone
square chin
vertical forehead
female skull characteristics
medium
obtuse mandible
smaller mastoid process
diminished brow bone
rounded chin
receding forehead
why is it difficult to determine race of bones?
mixed races
European eye orbits shape
oval
European nasal arpeture shape
long, narrow
European incisors shape
smooth
european cranium frontal plane shape
flat
Asian eye orbits shape
circular
Asian nasal arpeture shape
small, rounded
Asian incisors shape
shoveled interior
Asian cranium frontal plane shape
flat or projected outward
African eye orbits shape
square
African nasal arpeture shape
wide
African incisors shape
smooth
African cranium plane shape
projected outward
where does the most accurate determinations of age come from?
teeth
epiphyses (growth plates) fusion
cranial sutures
what age range is the most difficult to determine from bones?
25-40
what happens to bones after age 40
significant wear and tear on bones
when do elbow bones fuse
ages 9-13
when do pelvic bones fuse
ages 20-25
when does the lambdoid suture fuse
starts at 21, ends at 30
when does the sagittal suture fuse
age 35
when does the coronal suture fuse
starts at 48
ends at 50
entomology
study of insects and their relation to criminal investigation
helps determine time of death through insects reproduction cycles
post mortem interval (PMI)
determined by the oldest stage of the fly
what is the most common insect investigated in entomology? when does it arrive
blowfly
24 hrs after death
factors that affect body decomposition
temp
depth of burial
access by insects (develops in predictable stages), arrives to corpse like clockwork
stage 1 of decomposition
fresh/initial decay
- 0-3 days after death
- inside body: autolysis by bacteria and digestive enzymes
- outside body: flies attracted, lays eggs near wounds and natural body openings
stage 2 of decomposition
bloat/putrefaction
- 4-10 days after death
- inside: swelling from gas buildup from bacteria
- outside: flies and maggots feed in large quantities
stage 3 of decomposition
decay/black putrefaction:
- 10-20 days after death
- inside: skin breaks, gases and fluids leak out, anything exposed turns black
- outside: very large maggots, horrible odor, skin slippage, hair loss
stage 4 of decomposition
post-decay
- 20-50 days after death
- inside: mostly hair, skin, and bones
- outside: beetles eat skin and ligaments
stage 5 of decomposition
dry and skeletal:
- 50-365 days after death
- inside: only bones
- outside: moths eat hair
anterior
in front of
posterior
in the back of
superior
toward the upper portion of the body
inferior
toward the lower portion of the body
lateral
away from the middle of the body
medial
toward the middle of the body
proximal
toward/nearest the trunk/point of origin of a body part
distal
away/farthest from the trunk/point of origin of a body part
