FORENSIC PATHOLOGY

what is the general rate of body cooling / algor mortis?

1.5 degrees per hour/first 12 hours 1 degree per hour/next 12-18 hours

how long after death would it take for Tardieu spots to present?

18-24 hours

how can insects/bug activity help us learn more about evidence of trauma?

breaks in tissue provide high moisture content and protection to insects/encourage them to lay eggs - flies are attracted to areas of trauma and maggots are attracted to semen

this pioneer of autopsy developed method of performing autopsies in which he'd remove all organs individually and dissect them

Rudolph Virchow

what is the difference between Tardieu spots and petichiae

Tardieu spots are larger than petichiae Tardieu spots are post-mortem petichiae are pre-mortem

how does a muscle contract?

calcium unblocks binding sites on actin allowing it to bind to myosin fibers

what would the process of an internal exam/autopsy entail?

Y shaped incision dissect organs look for post-mortem changes

cadaveric spasm

a rare form of muscular stiffening that occurs at the moment of death and can be mistaken for rigor mortis *associated with violent deaths that occur under extremely physical circumstances with intense emotion

autolysis starts to digest these first/these to a lesser degree

carbohydrates and proteins fats

what may cherry red lividity indicate in terms of cause of death?

carbon monoxide poisoning cyanide poisoning cold temperatures

how can insects/bug activity help us learn more about geographic origin of remains?

certain species of insects originate in specific geographic locations

what would one see first in the eyes post-mortem?

clouding of the cornea

what are the three things one would see in the eyes post mortem?

clouding or cornea tache noir sludging/intravascular coagulation of retinal vasculature

this arthropod cause superficial feeding artifacts/eat superficial layers (can look like burn/parchment-like skin)

cockroach (dictyoptera)

what leads to fixation of livor mortis?

cooling solidifies dermal fat which closes capillaries

tache noir

dark band of dried epithelium in the eye from eye not being totally closed

what is an accidental manner of death?

death caused by violent means, not due to the intentional or criminal act by another person

what is a natural manner of death?

death caused exclusively by disease

what are some examples of reportable cases of death?

deaths from violence, trauma gunshot/stab wounds car accidents burns/blunt force injuries asphyxiation sudden/unexpected deaths environmentally related deaths decomposed bodies unknown/unclaimed bodies deaths from controlled substances certain fetal/maternal deaths deaths in prison/public institutions deaths under suspicious/unusual circ.

silphids and dermestid beetles feed off of

decomposing flesh

what do Tardieu spots indicate in terms of decomposition?

decomposition is rapidly approaching

algor mortis

decrease in body temp after death

autolysis is triggered by this

decrease in intercellular PH

what is the purple color of the deoxygenation of hemoglobin called?

deoxyhemoglobin

frass is produced by this type of beetle

dermestid

what is the gross appearance of someone post mortem?

distortion of facial features distention of abdomen and scrotum

how can insects/bug activity help us learn more about presence of drugs?

drugs are deposited in fat bodies and chitin or exoskeleton

what would be some things you would look for in a toxicological exam?

drugs/alcohol gastric/blood contents vitreous humor from eye (clear gel that fills space between lens and retina)

what are the qualifications for a coroner?

elected position may or may not be an MD/DO 18+, registered voter, high school grad

bullae formation occurs when

epidermal junction seperates

which parts of the body would you see mummified?

exposed body parts - fingers, toes, face

an autopsy could include these 4 areas of examination

external internal microscopic toxicological analysis

mummification is seen in what climates?

extremes of hot and cold

what could autolysis in the pancreas be confused for?

fat necrosis

how long does adipocere formation take?

few days (if warm and moist) to weeks or months or longer periods in dry environments

how does rigor resolve?

actin detaches from ends of sarcomere causing the contractile unit to lengthen again

with this type of decomposition, you would have hydrolysis and hydrogenation of fats to fatty acids

adipocere formation

these make up 1-4% of enterococci and proteus

aerobes

when do beetles colonize a body?

after flies - could be some of the last insects to colonize body

what are 2 things that help determine when rigor sets in?

ambient temperature metabolic state at time of death

these make up 96-99% of bacteria in colon, bacterioides (normal gut bacteria), clostridia

anaerobes

what are some possible factors with decomposition?

animal artifacts insect activity buried bodies submersed bodies

what are the six areas of forensic science?

anthropology odontology entomology ballistics botany toxicology

these two arthropods can feed on skin

ants/cockroaches

cause of death means:

any injury or disease that produces a physiological derangement in the body that results in the individual dying

qualifications for medical examiner

appointed position almost always MD/DO usually forensic pathologist

Tardieu spots are only seen in what areas?

areas of lividity

frass

beetle poop (very dry, fragmented easily)

what is the course of skin color change post mortem?

biliverdin (green) bilirubin (red) urobilin (brown) hydrogen sulfide (black)

what are the three types of decomposition?

bloating mummification adipocere formation

areas with lots of this decompose the quickest and why?

blood - blood is good conduit for bacteria

what initially causes clotting of blood post mortem?

blood becomes acidic due to tissue breakdown which causes an activation of the intrinsic coagulation pathway

beetles may infiltrate these parts of the body

bone marrow sinuses

larval maggots do this to skin

bore holes

livor mortis is fixed when shifting/drainage of blood no longer develops due to ...

breakdown and hemolysis of blood vessels

as decomposition progresses, PH decreases which activates these which eventually re-liquifies blood

fibrinolysins

what are the 4 stages of maggots?

fly eggs maggots pupae adult fly

beetles mostly feed on

fly eggs and larvae

how can insects/bug activity help us learn more about time of death?

insects go through different stages of life/sizes throughout PMI

how can insects/bug activity help us learn more about movement of body and storage of remains?

if you see successive or intermittent broods of insects it could indicate the body has been moved or stored a certain way (inside/outside, etc)

how does rigor mortis affect all muscles of the body?

involves all muscles at the same time/same rate

where are three places one would commonly see rigor?

jaw, upper and lower extremities

what is the chemical cause of rigor mortis?

lack of ATP in muscle

adipocere formation requires...

lipids

where would one see gas bubbles post mortem?

liver and other solid organs

autolysis begins sooner in organs with abundant...

lysosomes

these can mimic body drag marks

maggot migration trails

adipocere forms this type of compound

malodorous cheesy compound

intravascular hemolysis (decomposition of blood vessels) results in what appearance of the skin?

marbling

what are some chemical productions of decomposition (8)?

methane hydrogen hydrogen sulfide carbon dioxide alcohol ammonia putrescine cadaverine

how long does it take for a body to become mummified?

months to years

if you see frass on a body, what is the approximate PMI?

months to years

what are the 5 manners of death:

natural accidental suicide homicide undetermined

what is an undetermined manner of death?

no determination re: manner of death can be made after an autopsy and investigation

would something like sepsis be a cause of death?

no- you would need to find out what caused the sepsis - the cause of that would be the cause of death

what happens to the sarcoplasmic reticulum allowing for rigor mortis to set in after death?

sarcoplasmic reticulum loses integrity and allows for calcium ions to enter into the sarcomere

the presence of beetles usually means the body has been in this type of environment

sheltered

where is rigor mortis most evident?

smaller muscles / gradually evident in larger muscle groups

what are some examples of a cause of death?

stab wounds pneumonia carcinoma (something that starts a chain reaction resulting in death)

rigor mortis

stiffening of muscles after death

what do gastric contents tell you about time of death?

tells time interval btwn eating and death

if rigor mortis is inconsistent with gravitational forces, what may this indicate?

the body was moved

what are some things forensic entomology can help us learn re: death/crime?

time of death season of death geographic origin of remains movement/storage of remains evidence of trauma presence of drugs

Tardieu Spots

type of lividity -when pressure of lividity ruptures blood vessels causing skin hemorrhages

what is a homicide/manner of death?

violent death at the hand of another person due to a hostile/illegal act of that person

what is a suicide/manner of death?

violent death caused by an act of the decedent with the intent to kill onself

what chemical in the body increases as PMI increases?

vitreous potassium

these two arthropods are the major predators of fly eggs and larva

wasps (hymenoptera) and ants

where does adipocere decomposition typically take place?

wet/damp environments

what are some things to consider when determining whether a death is a suicide?

what was the intent of the decedent? was there a perceived risk involved in the death?

when would one use a microscopic exam/autopsy?

when one needs confirmation of something you can't see grossly

what is the difference between the marks from contusions and lividity?

with contusions, blood is extra-vascular with local accumulation with lividity blood is intravascular

how does ambient temperature affect rigor mortis?

-cold accelerates and prolongs rigor -warm or hot delays rigor or may never form at all

how long do flies pupate before becoming a mature fly?

1 week

what is the order of tissue decomposition?

1) intestines, stomach, heart, blood, digestive organs, appendix 2) air passages and lungs 3) kidneys and bladder 4) brain and nervous tissue 5) skeletal muscle 6) connective tissue 7) bone

at what point to maggots find a dark place to pupate?

1-2 weeks

how long after death does rigor mortis begin?

2-4 hours

fly eggs hatch into first stage maggots after how long?

24 hours

how long post mortem until livor mortis sets in?

30 minutes to 2 hours post death

how long after death does it take for rigor to resolve?

36 hours

at one instar stage do maggots go to find a place to hide/cause maggot migration trail?

3rd instar stage

how long before livor mortis is fixed?

8-12 hours after death

how does a muscle relax?

ATP-drive transport pumps calcium back into the sarcoplasmic reticulum resulting in detachment of actin-myocin complex

this pioneer of the autopsy developed method of performing autopsies in which he'd open all organs in situ

Karl Rokitansky

who signs off on unnatural death certificates?

ONLY ME/coroner

what are the 4 stages of decomposition?

fresh: no ext signs of decomp early: some lividity advanced: skin slippage, etc skeletonization

what would one be sure to note in an external exam/autopsy?

hair/eye color scars, tattoos state of dentition natural disease skin malignancies any trauma *document everything

what is the skin of someone who is mummified?

hard, leathery, forms shell

what type of artifact do maggots produce?

holes in tissue/not bone

manner of death means:

how the cause of death came into being

what may minimal lividity indicate?

hypovolemic shock/anemia

how does one's metabolic state affect onset of rigor mortis?

if one has a fever or is physically active when they die (drowning, etc), rigor may proceed quickly

how can one tell between livor mortis and bruising/contusion?

if you press on that part of the body, the skin will not blanch

autolysis

organs breaking themselves down

with livor mortis, skin turns red to purple as what happens?

oxygen dissociates from hemoglobin of RBC's

where would you see first signs of autolysis?

pancreas

chemically, how does one's physical activity at time of death affect rigor?

physical activity increases lactic acid which promotes release of calcium ions into sarcomere

what happens to the capillaries when livor mortis is not fixed (skin able to be blanched)

pressures force blood from capillaries

peritrophic membrane

protective covering on beetle fecal matter

cathepsins

proteolytic enzymes which can increase release of the actin from the sarcomere allowing for resolution of rigor

how can insects/bug activity help us learn more about season of death?

pupae and exoskeletons may remain for years, giving us indication re: season of colonization

livor mortis

purple/red discoloration due to accumulation of blood after death

this drives bloating decomposition

putrefaction

skin slippage occurs due to

release of hydrolytic enzymes at dermal/epidermal junction

if a person is dead, ATP is no longer present - relaxation cannot occur and contraction persists as this...

rigor

why would one see goosebumps post mortem?

rigor in muscles of hair follicles

why would one see post-mortem ejaculation?

rigor in muscles of seminal vesicles push semen out after death

what are three major changes that occur in the body after death?

rigor mortis algor mortis livor mortis