Path Summer 1
What types of damage to bone occur as a result of canines?
"V" shaped injury Punctures Pits Scoring Furrows
Tardieu spots
A type of lividity that occurs when the PMI increases (18-24hrs) and BVs rupture as a result of the pressure from the blood accumulating in lividity
What other bacteria are responsible for Putrefaction in the colon/bowel?
Aerobes (enterococci, proteus) 1-4% of bacteria in colon/bowel
Why does fixed LM occur?
After being in one position for long enough, the fat surrounds and closes off the capillaries of blood vessels so that the blood can't escape
When do beetles typically begin to colonize bodies?
After flies and maggots since they like to feed on fly eggs and larvae
Three basic things we can look at to help determine time of death
Algor Mortis Livor Mortis Rigor Mortis
Medical Examiner
Appointed position, almost always a physician and usually a board certified forensic pathologist
Where does one of the earliest signs of decomposition occur?
Around the appendix
Coroner
Elected position (you only need to be 18y/o, a registered voter, and have a high school diploma)
Are Tardieu spots larger or smaller than petechiae?
Larger! And they're only found in areas of lividity
What finding might be confused w/ drag marks?
Linear marks from 3instar maggots crawling away to pupate
What pm change may falsely lead you to think that the patient had pneumonia?
Livor Mortis in the lungs! It can mimic pneumonia
Adipocere formation
Malodorous, cheesy compound that results when a body is placed in a moist environment
Accident death
Manner of death caused by violent means not due to intentional or criminal act by another person
Natural death
Manner of death caused exclusively by disease (MI, stroke, sepsis, etc.)
Undetermined death
Manner of death which, after a complete autopsy/investigation of circumstances, doesn't have a determined cause
Homicide death
Manner of violent death at the hand of another person due to a hostile or illegal act of that person (i.e. gunshot wound)
Suicide death
Manner of violent death caused by an act of the decedent w/ the intent to kill himself
Which gas mostly causes distention of the abdomen and scrotum?
Methane
What are the products of decomposition produced by bacteria?
Methane (bloating) Hydrogen Hydrogen sulfide Carbon dioxide Alcohol Ammonia (amino acids break down --> release nitrogen, form ammonia)
Viracow method of autopsy
Method of autopsy that looks internally and then takes organs out separately
Rokitansky method of autopsy
Method of autopsy that takes all of the organs (from the tongue to the rectum) out in one big block
Will someone who is very muscular have more significant or less significant Rigor?
More significant
What type of decomposition tends to be seen in dry areas, extremes of hot and cold, and indoor deaths?
Mummification
What color is urobilin?
brown
Livor Mortis
Purple/red discoloration in the dependent areas of the body due to accumulation of blood after cardiac activity has ceased
What form of decomposition results in the gut as bacteria proliferate unchecked?
Putrefaction
What are the products of Putrefaction?
Putrescine Cadaverine Biliverdin Bilirubin Urobilin Hydrogen Sulfide
What is the difference b/w a rat indentation and a canine indentation?
Rats produce parallel striae with their incisors rather than V-shaped indentations
What color is bilirubin?
Red
Why does pm ejaculation occur?
Rigor Mortis occurs in the muscles of the seminal vesicles
What is "gooseflesh?"
Rigor mortis in the erector pillae muscles of the skin/hair follicles
Typically, beetles like to feed on remains in what location?
Sheltered, dried, and mummified**
What changes occur during advanced decomposition?
Significant color changes, bloating, and some tissue loss
Which types of beetles feed on decomposing flesh?
Silphids and dermestids
What changes occur during early decomposition?
Skin slippage and color changes
Rigor Mortis
Stiffening of the muscles after death due to lack of ATP
Where to cockroaches tend to feed?
Superficial keratinized portions of the epidermis
True or False: Rigor Mortis involves all muscles at the same time and at the same rate
TRUE
True or False: Rigor resolves more quickly in a warm environment
TRUE
True or False: larval masses can move remains
TRUE
True or False: lividity becomes darker the longer that a person is dead
TRUE
What changes occur during fresh decomposition?
The body has just died, may have some rigor or algor mortis
What does it mean if rm is inconsistent w/ gravitational forces?
The body was moved!
Cadaveric spasm
The instantaneous type of rigor mortis
What might happen to solid organs during decomposition?
They tend to get spongy from gasses expanding and creating bubbles
What is "unfixed" LM?
When you press on the LM and it blanches
What is "fixed" LM?
When you press on the LM and it doesn't blanch
What color will plant matter be if it is growing towards a body?
Yellow tinged "chlorosis" from the body's amino acids
Which parts of the body will canines tend to feed on first?
face, neck, hands then, thorax, upper extremities, clavicles as the body decomposes- makes it easier to disarticulate long bones, etc.
Skeletal remains degrade more quickly in a wet environment or an ____/_____ environment
acid/alkaline
What color is hydrogen sulfide?
black
What produces cadaverine?
breakdown of amino acids
What produces putrescine?
breakdown of amino acids
In what order to the tissues tend to decompose?
intestines/heart/stomach/blood/digestive organs air passages and lungs kidneys and bladders brain and nervous issue skeletal muscle connective tissue
If beetles are feeding, how long is the PMI?
months to years
Autolysis begins sooner in which organs?
those w/ abundant lysosomes
What happens to the vitrous potassium as the time since death increases?
vitrous potassium increases as well (not in a predictable way, though)!! (vs. vitreous glucose, which decreases)
What groups of people may have minimal lividity?
1) Anemic 2) Those who were stabbed/shot and became hypovolemic They both have dec. circulating volume
What does cherry red lividity indicate?
1) Carbon monoxide poisoning 2) Cyanide poisoning 3) Cold temperatures
How long does it take a body to skeletonize if buried at a depth of 4+ feet?
2-3yrs
When does Rigor Mortis usually begin?
2-4hrs after death OR if they're using a lot of ATP at the time of death, it can begin much more quickly
When does Livor Mortis begin?
30min-2hrs after death
When does Rigor Mortis typically resolve?
36hrs
What stage of development does a fly/maggot need to be in in order to determine the species?
3rd instar
What is a lethal CO2 level?
40%
How long does it take a body to skeletonize if buried at a depth of one foot?
6mo
When does Livor Mortis usually become fixed?
8-12hrs after death
Forensic pathology
A branch of medicine that applies the principles and knowledge of the medical sciences to problems in the field of law
What is biliverdin and what color is it?
A breakdown product of blood- has a green color to it
Algor Mortis
A decrease in body temperature after death
What is a peritrophic membrane?
A protective covering of beetle fecal matter, also known as beetle frass
How long does it take a fly to go from an egg to a mature, adult fly?
About 2wks
What is Rigor Mortis determined by?
Ambient temperature and metabolic state at the time of death
What kind of bacteria in the colon/bowel are most responsible for Putrefaction?
Anerobes (bacteroids, clostridia) Account for 96-99% of bacteria in the colon/bowel
What must purge fluid be differentiated from?
Antemortum trauma (since it can be blood tinged)
Cause of death
Any injury or disease that produces a physiological derangement in the body that results in the individual dying (cancer, pneumonia, etc.)
What are the four breakdown products of hemoglobin?
Biliverdin Bilirubin Urobilin Hydrogen Sulfide
What type of decomposition is typically seen in cities and moist areas?
Bloating
What is a secondary grave depression?
Bloating causes movement of soil, followed by collapse back down when bloating resolves
What areas of the body will begin to decompose first?
Blood rich areas (lividity)
Forensic anthropology
Branch of pathology that deals predominantly w/ skeletal remains (determining height, etc.)
Forensic odontology
Branch of pathology that deals w/ dentistry, can identify remains using teeth, examine bite wounds, etc.
Forensic ballistics
Branch of pathology that deals with bullets and firearms
Forensic botany
Branch of pathology that examines the plant activity growing around the body, can help you determine how long body has been there
Forensic toxicology
Branch of pathology that looks into ETOH use, drugs of abuse, etc.
Forensic entomology
Branch of pathology that studies bugs (insects that colonize your body when you die, etc.)
How is scoring typically produced?
By the molars of the dogs, producing grooves in the bone
Vitreous humor glucose level
Can be used during an autopsy toxicological analysis to see how long the person has been dead (glucose decreases as PMI lengthens)
Besides tache noir, what are the other two post-mortem eye changes that take place?
Clouding of the cornea early on Sludging and intravascular coagulation of retinal vasculature
What species can cause superficial feeding artifacts of the skin that look like thermal burns?
Cockroaches
What species may feed on the eyebrows b/c of their big mouths?
Cockroaches/dictyopetera
What is another name for cockroaches?
Dictyoptera
Tache Noir
Dark band of dried epithelium on the sclera when the eyes don't close completely
Why does bullae formation occur?
De-compositional fluid expands between the dermis and the epidermis
Putrefaction
Decay/rotting produced by bacteria that contributes to decomposition
What is purge fluid?
Decomposed gastric lining and contents that expand up and out of the nose and mouth
What do Tardieu spots indicate?
Decomposition that is rapidly approaching
Does clean water increase or decrease decomposition?
Decrease
Does salt water increase or decrease decomposition?
Decreases b/c it acts as a bactericidal
What changes can plant material make to a body?
Degrade clothing Degrade tissue Cause grooving of the outer bone cortex
What beetles produce peritrophic membranes?
Dermestid beetles
True or false: temperature decreases at a readily detectible level in Algor Mortis
FALSE
True or False: maggots/larvae can create bore holes through bone
FALSE- only tissue
Where might drugs be deposited in the exoskeleton of an insect that was feeding off of a dead body?
Fat bodies and chitin of the exoskeleton
Where does adipocere formation typically occur in the body?
Fatty portions like the brain
What are the four stages of decomposition?
Fresh Early Advanced Skeletonization
Where does tissue decompensation occur first?
G tract b/c that's where the bacteria are
What is adipocere formation also known as?
Grave wax
At what rate will a submerged body decomposed compared to a body that decomposes in air?
Half of the decomposition rate of air
What causes adipocere formation?
Hydrolysis and hydrogenation of fats to fatty acids
What is another name for wasps?
Hymenoptera
Where is Rigor Mortis most evident?
In smaller muscle groups!! It gradually becomes more evident in larger muscle groups
What is marbling?
Intravascular hemolysis (as blood vessels decompose, they give the body a marble pattern like a statue, table, etc.)
Should a body with no maggots skew your idea of the PMI?
No, because ants and wasps may have eaten the maggots
Where do female flies usually lay their eggs?
On a food source in a moist environment (eyes, mouth, nose) with protection from solar radiation
In what environments will a body decompose most rapidly?
On the surface of the ground most rapidly, then when the body is in water, and then when the body is buried
What is a primary grave depression?
Outline of the grave from settling of soil
How can you break Rigor Mortis?
Passive stretching of the muscles
External autopsy examination
Portion of autopsy that looks for things like pitting edema, skin lesions, etc.
Internal autopsy examination
Portion of autopsy that uses either the Rokitansky or Viracow method to examine the organs
Why is LM typically red-purple?
The oxygen is dissociating from hemoglobin, and deoxyhemoglobin is typically purple
Pedestal phenomenon
When rodents chew away the epiphyseal cartilage (the softest part), leaving adjacent areas of long bone on a 'pedestal' since the epiphysis and metaphysics are still attached
What two other arthropods colonize the body and like to feed on fly eggs and larvae?
Wasps and ants
What determines when a submerged body will resurface?
Water temperature
What is autolysis?
hydrolytic enzymes released by lysosomes, triggered by a decrease in cellular pH
What is skin slippage?
release of hydrolytic enzymes at the dermal/epidermal junction, allowing the epidermis to slough off of the dermis like a glove/sock