Pathology Exam
Damage to bone from rodents - what does it look like?
Continuously growing incisors Upper incisors pressed into the bone while the lower incisors move up and down ==> parallel striae May transport bone back for nesting purposes
Algor mortis - rate at which the body cools
1.5 degrees F per hour for the first 12 hours Then 1 degree F per hour for the next 12 to 18 hours
Tardieu spots - how long does it take to form?
18 - 24 hours
What happens if a body is buried four feet or more below? How long does skeletonization take place?
2 - 3 years
Dipteran life cycle
Adult female lay eggs on or near food Need moisture Need protection from solar radiation Will go into nasal passages, corners of mouth or folds of clothing and eyes
Drug induced deaths - difference between overdose
Adverse effects of drugs. May not have large amounts of drugs in the system but at a given time their body acted adversely and then they die.
3 things used to determine time of death
Algor Mortis Rigor Mortis Livor Mortis
Medical examiner qualifications
Appointed position Almost always a physician Usually a forensic pathologist
What does scavenging of remains by canines result in?
Disarticulation and scattering of remains produces artifacts alters antemortem injuries
What happens to the facial features postmortem?
Distortion
Coroner qualifications
Elected position May or may not be a physician (18, registered voter, high school diploma)
What is the pedestal phenomenon?
Epiphyseal cartilage and adjacent areas of long bones
PM chemical changes - vitreous potassium
Increases as time since death increases highly variable controlled by rate of decomposition
What happens if a body is in a shallow grave?
Less than 1 foot: odors easily penetrate the soil, attracting insects and carnivores. Bloating decomposition cracks the soil
Adipocere formation - what does it require?
Lipids, longer periods in a dry environment
What are products of decomposition?
Methane Hydrogen Hydrogen sulfide Carbon dioxide ETOH Ammonia
What is livor mortis?
Purple/red discoloration in the dependent areas of the body d/t accumulation of blood after cardiac activity has ceased.
Products of putrefaction
Putrescine Cadaverine Biliverdin (green) Bilirubin (red) Urobilin (brown) Hydrogen Sulfide (black)
What is skin slippage? What will you see?
Release of hydrolytic enzymes at dermal/epidermal junction Bullae formation Hair and nails do not grow postmortem Marbling: Intravascular hemolysis
Scavenging of remains by canines - what happens?
Removal of soft tissue of face and neck Destruction of ventral thorax and upper limbs, clavicles Lower limbs detached Disarticulation of long bones DIsarticulation, gnawing and scattering of all or most bones
Manner of death - Russian roulette, what is the manner of death?
SUICIDE - if you get a loaded gun and place it to your head and pull the trigger, there's the intent that they want to kill themself.
Rigor mortis - where is it most evident?
Smaller muscles and gradually becomes evident in larger muscle groups -Jaw, upper ext, lower ext
Rigor Mortis - definition, why?
Stiffening of the muscles after death Due to a lack of ATP
Say the same guy with seizures was controlled on medication and then decides to stop taking it, has a seizure and dies. What's the manner of death?
Still homicide, because wouldn't be in that situation.
What does it mean if RM is inconsistent w/ gravitational forces?
The body was moved after death
Tardieu spots - larger than petechiae?
YES
Will livor mortis shift before being fixed?
Yes
Livor mortis - does it darken as time goes on?
Yes "darkens as PMI increases"
Burned remains - what does it do to insects?
can be a deterant, or can give better access to internal structures
why do bodies decompose slower in water than in air?
cooler temperatures and decreased insect activity
Livor mortis - what does it mean when it's fixed?
cooling solidifies dermal fat and closes capillaries When shifting or drainage of blood no longer develops d/t breakdown and hemolysis of BVs
What is purge fluid?
decomposed gastric lining and contents
Rigor mortis - How is it lost?
decomposition
Does clean water increase or decrease decomposition?
decrease
Does salt water increase or decrease decomposition?
decrease
What happens to the abdomen and scrotum postmortem?
distention - methane gas
Mummification - when does it occur?
extremes of hot and cold
What are the types of decomposition?
bloating mummification adipocere formation
What is the secondary grave depression?
bloating causes movement of soil followed by a collapse
Which areas decompose first?
blood rich areas
What do maggot artifacts look like?
larval bore holes Movement of remains by larval mass Maggot migration trails mimic drag marks
Adipocere formation - definition
malodorous cheesy compound
Gastric emptying and digestion - what can it tell you?
time interval between eating and death - time varies depending on the content of the meal (fat takes longer)
Do plants grow toward or away from a corpse?
toward seeks organic nutrients may degrade clothing, tissue, and cause grooving of the outer bone cortex
Do bodies resurface as decomposition ensues?
yes
Rigor mortis - does it involve all the muscles at the same time and rate?
yes
Do skeletal remains degrade quicker in wet environments? What if too acid or alkaline?
yes, it will degrade quicker
Order of tissue decomposition
1. Intestines, stomach, heart, blood, digestive organs. 2. Air passages and lungs 3. Kidneys and bladder 4. Brain and nervous tissue 5. Skeletal tissue 6. Connective tissue - ligaments, bones, etc.
What happens if a body is buried one foot below? How long does skeletonization take place?
6 months
Elderly in nursing home has osteoporosis and other medical problems, falls and fractures the femoral neck and dies w/in 3 weeks of the hip fracture. What is the manner of death?
Accident
Guy tries to shoot another person but ends up shooting himself on accident. What is the manner of death?
Accident
You are at a pool and you see an 85 y/o male swimming. Tells you he's having chest pain thats radiating to the left shoulder and then sinks. You jump in to do CPR and he doesn't make it. Autopsy reveals 95% occlusion of LAD and pulmonary edema. What is the manner of death?
Accident. Because he died drowning.
Putrefaction - m/c type of bacteria
Anaerobes 96 - 99% of bacteria in colon, bacteroids, clostridia Aerobes 1 - 4% enterococci, protus
What are postmortem factors?
Animal artifacts Insect activity Buried bodies Submerged bodies
Cause of death - definition
Any injury or disease that produces a physiological derangement in the body that results in the individual dying
What drives decomposition?
Bacteria
What can be one of the last insects to colonize a body?
Beetles
Rigor mortis - how long does it take to set in, when does it resolve?
Begins 2 - 4 hours after death Resolved by 36 hours
Livor mortis - how long does it take to set in, when does it resolve?
Begins 30 min to 2 hours after death. Usually "fixed" by 8 - 12 hours after death
Where in the body do beetles hide in?
Bone marrow or sinuses
Forensic Pathology - Definition
Branch of medicine that applies the principles and knowledge of the medical sciences to problems in the field of law.
What will produce "cherry red lividity?"
Carbon monoxide poisoning, cyanide poisoning, and cold temperatures
Autolysis - what does it digest?
Carbs and proteins Fats to a lesser degree
Postmortem eye changes
Clouding of cornea Tache noir Sludging and intravascular coagulation of retinal vasculature
What can lividity be confused with?
Contusion
What is tache noir?
Dark band of dried epithelium on the eye
Manner of deaths - accident definition
Death caused by VIOLENT means, not d/t the intentional or criminal act by another person
Manner of deaths - natural definition
Death caused exclusively by disease. m/c and makes up a large percentage.
Reportable cases to the medical examiner
Deaths resulting from violence (GSW, stab, MVA, burns, blunt force injury, asphyxiation) Sudden unexplained deaths Environmentally related deaths (hyper/hypothermia) Decomposed bodies Unknown or unclaimed individuals Deaths from controlled substances (drugs, ETOH) Deaths in prison or public institutions Certain fetal and maternal deaths Deaths under suspicious or unusual circumstances
Tardieu spots - what does it mean?
Decomposition is rapidly approaching
What is algor mortis?
Decrease in body temperature after death
Autolysis - what is it triggered by?
Decrease in intracellular pH Hydrolytic enzymes released by lysosomes
Rigor mortis - influences
Determined by ambient temperature, metabolic state at time of death Cold and freezing delay onset and prolongs it's presence.
Parts of an autopsy
External exam Internal exam Microscopic exam Toxicological exam
Mummification - defintion.
Fluid loss via evaporation Skin is hard, leathery, forms a shell Exposed parts of the body - fingers, toes, face
Beetles - where do they feed?
Fly eggs and larvae Some feed directly on decomposing flesh - silphids and dermestids
What are the stages of decomposition?
Fresh Early Advanced Skeletonization
Gastric emptying and digestion - how is it variable?
Great variability between different individuals Great variability between the same individual at different times
Guy walks into a bank and he puts a mask on head and pulls out gun and yells, "GIVE ME MONEY." The teller grabs chest and dies. Autopsy reveals 95% occlusion of LAD but no trauma? Manner of death?
HOMICIDE - because the guy pulled the gun on him and he collapsed right there and then.
Guy is walking down the stree in Philly and a gun fight between 2 gangs breakout, he gets hit in C3 w/ bullet and cannot walk anymore. He lives for 10 years and then develops pneumonia and sepsis and then dies. Manner of death?
Homicide - would not be in that position had he not been shot
Guy sustains a GSW, states allergy to penicillin but penicillin is given anyway, has anaphylactic rxn and dies. What is the manner of death?
Homicide, because of the guy that shot him. He wouldn't have been subjected to the penicillin had he not been shot.
65 y/o male starts making sexual advances toward a 19 year old guy (nothing aggressive). 19 year old boy beats up 65 year old. 65 y/o guy survives but then he develops a sz d/o. 3 years later he seizes and dies. Manner of death?
Homicide.
Manner of death - definition
How the cause of death came into being
Adipocere formation - what is the chemical process?
Hydrolysis and hydrogenation of fats to FA
What will produce minimal lividity?
Hypovolemic shock or anemia
Adipocere formation - when will it occur?
In a few days of warm and moist
Tardieu spots - can they occur outside of areas of lividity?
NO
Guy gets bit by a deer tick, 6 months later dies from a heart block. Manner of death?
Natural
Manner of deaths - types
Natural Accident Suicide Homicide Undetermines
Rigor mortis - what can break it?
Passive stretching of muscles Once broken it does not generally return unless it is only partially formed.
What do beetle artifacts look like? what is the PMI at this point? What type of beetles?
Peritrophic membrane: protective covering on beetle fecal matter PMI: at this point months to years remains were sheltered drying and mummification Dermestid beetles
What are tardieu spots?
Pressure of lividity ruptures blood vessels causing skin hemorrhages
Canines - damage to bone - what does it look like?
Produce a "v" shaped injury punctures pits scoring furrows
What can forensic entomology tell us?
Time since death Season of death - pupae and exoskeletons may remain for months or years Geographic origin of the remains: some species range in certain areas Temperature dependent Movement or storage of remains - insects can be trapped Evidence of trauma - moisture content Drugs
Guy is assaulted, doesn't have a sz d/o before he is assaulted, then develops a sz d/o and is given phenytoin. Then he develops an abscessed tooth and was given penicillin. Breaks out in a rash, prior to NKDA. Get's TEN --> dies. Whats the manner of death?
UNDETERMINED If the penicillin caused it, accident. If the phenytoin caused it, homicide.
What happens to the bacterial flora postmortem?
Uncontrolled growth of bacteria and fungi --> production of gases and aromatic organic compounds
Manner of deaths - homicide definition
Violent death at the hand of another person d/t a hostile or illegal act of that person
Manner of deaths - suicide definition
Violent death caused by an act of the decedent with the intent to kill him/herself
What are other arthropods that feed on the decomposing body?
Wasps and ants - predators of fly eggs and larvae Cockaroaches - superficial feeding artifacts Ants produce artifact
What can you see in the liver and other solid organs post mortem?
gas bubbles
Bodies in aquatic environments decompose at a rate of _____ of decomposition in air
half
What is the primary grave depression?
outline of the grave from settling of the soil
Livor mortis - why does it look red to purple?
oxygen dissociates from hemoglobin of hbc's Deoxyhemoglobin = purple
What is post mortem ejaculation?
rigor mortis in muscle of seminal vesicles
What is gooseflesh?
rigor mortis in muscles of hair follicles (Erector pili)
