forensic pathology - lecture notes - julia Flashcards
1
Q
what are the five possible manners of death?
A
- natural
- accidental
- suicide
- homicide
- undetermined
2
Q
what proportion of people who die are investigated by the ME’s office? how many recieve an autopsy?
A
- about 12,000 people die in NH in a calendar year
- 1500 to 1800 of these deaths will be reported to the ME’s office
- only 500 will require an autopsy - the others will have enough information in their patient records and external examination to deterimine cause and manner of death
3
Q
what are the 25 things that are reportable to the ME’s office in NH? (i don’t think we have to memorize this - i’m bolding the ones he talked about)
A
- Death resulting from a criminal act, regardless of time interval between incident and death
- Suicide, regardless of time interval between incident and death
- Death resulting from accidental injury, regardless of time interval between incident and death
- Deaths associated with fire or explosion
- Deaths associated with firearms or other mortal weapons
- Death in associated with any public or private conveyance
- Illegal abortion or complications thereof
- Death due to poison, illicit drug use or overdose
- Exposure to toxic agent during course of employment
- Deaths resulting from agents which constitute a public health or environmental hazard
- Sudden, unexpected death of a person under 60 in apparent good health
- Death unattended by a practicing physician
- Death in legal custody – dying while incarcerated, in police car, under arrest, handcuffs, when police were on the scene
- Deaths associated (not caused by!) with diagnostic or therapeutic procedures, including intra- and perioperative deaths – even if died during some benign appearing imaging study, must be reported to ME
- Death in which a body is to be cremated – about 5000 people per year – more or less a clerical check than anything else
- Deaths occurring less than 24 hours after admission to health care facility, save for those known to be terminally ill from natural disease and death is imminent and expected – unless clinician comfortable with certifying death (ie in a case where, even though he’s come into the ER and only been there for a bit, it’s clear why he died)
- Death of a child under 18 save for criteria above
- Death of a child from any cause when death occurs in day care, foster care or child is in custody of or being investigated by DCYF
- Fetal death resulting from trauma after 20 weeks or 350 gm - not every spontaneous fetal loss presumably due to natural causes is reportable – only if its traumatic such as a traffic accident, drug use, assault
- Death known to have been improperly certified
- Death of any unidentified person regardless of cause or manner
- Discovered buried remains, known or thought to be human
- Decomposed and skeletonized remains
- Suspicious or unusual circumstances surrounding a presumed natural death
- Death of a prominent or controversial person
4
Q
what is rigor mortis? why does it occur (mechanism)? how can it be used to establish time of death?
A
- stiffening of muscles
- because ATP spontaneously breaks down to ADP and the actin and myosin filaments lock together
- involves the smallest muscles first, so within 45 minutes of death will be detectable in the neck and jaw
- body is completely stiff by 18-24 hours after death
- body will remain stiff for another 24-36 hours depending on environmental conditions
- as body decomposes and muscles break down, body will become flaccid again
5
Q
what is livor? how can it be used to establish time of death?
A
- color
- blood will settle to the most dependent (bottom/closest to gravity) region of body
- solid elements will settle out and coagulate, fluid will become less and less fluid
- the early stages will blanche
- after 8-10 hours, no longer blanches
- can also tell you whether the body was moved
6
Q
what is algor mortis? what can it tell you about time of death?
A
- temperature change in the body
- declines at steady rate (depending on environment) so can calculate how long the body’s been dead
7
Q
what ocular changes occur after death? how can they help you establish time of death?
A
- filming, drying, clouding
- he said the only one he finds helpful is clouding:
- if the cornea is completely opacified and that wasn’t known to be due to some sort of disease process, than the body’s been dead for at least 72 hours
8
Q
what is the difference between putrefaction and mummification?
A
- putrefaction requires bacteria and a high humidity environment, will smell
- mummification occurs in a low humidity environment and doesn’t involve bacteria, won’t smell as much, like tanning leather
9
Q
what late post-mortem changes can be used to establish time of death? (6)
A
- putrefaction
- mummification
- infestation (different insects have developmental rates and these are consistent)
- skeletonization
- adipocere (development of wax-like substance by bacterial hydrolysis of fat)
- anthropophagy (eating of the body by animals)
10
Q
what happens during the initial decay stage? what bugs would you expect to see and what is the timing of their development
A
- enzymatic release and autolysis
- blowflies and house flies will lay eggs around wounds and mucosal surfaces
- eggs hatch and move into the body within 24 hours
- takes 2-3 weeks for the egg to develop into a maggot and then into a fly - considerably longer at low temperatures (rate depends on species - consult entymologist)
11
Q
what is the process of putrefaction (what’s happening during this process?) where will this process first be observable?
A
- bacteria break down the tissues, releasing fluids into body cavities
- anaerobic species produce gases including hydrogen sulfide, methane, cadaverine, and putrescine (he said he didn’t care about the specific gases, so i’m assuming we don’t need to know them…)
- gas “infiltrates” teh body and forces fluids into body cavities and out of the orifices
- since there’s lots of bacteria in the GI tract, particuarly the cecum, will see greening of the belly over the cecum first - apparently the skin is thinner here at least
12
Q
what occurs during infestation of the body?
A
- maggots move throughout the body, spreading bacteria, secreting digestive enzymes adn tearing tissues with their mouth hooks
- move as a mass benefiting from communal heat and shared digestive secretions
13
Q
what does skeletonization depend on? how long can it take in summer?
A
- time taken for a body to decompose depends on temperature and moisture and accessibility to insects
- in summer, in an exposed location, human body can be reduced to bones in just 9 days
14
Q
what is the chain of custody? why is it important?
A
- chain of people through which evidence is transfered
- must be proper paperwork and such filled out at every step of the chain
- evidence won’t be admissible in court if the chain is not properly followed
- properly packaged and labled evidence is securely maintained
15
Q
what are the three layers of the external autopsy?
A
- inspected first as it arrives at the morgue - should be exactly as it was found at the scene
- body is disrobed and examined again
- if there’s any external findings, these are cleaned and detailed images and sketches are taken of them
- only after these three external autopsy steps are taken is the body cut open
19
Q
how would you determine if someone was hanged or strangled?
A
- someone strangled will likely have a ligature mark directly across the throat (where it is on this patient)
- someone hanged or how hanged themselves would have a more diagonal ligature mark from mandibular bone to mandibular bone (more along the black line)
20
Q
what do human bite marks look like?
A
- area of central clearing and then a circular bruise around it
- often tears in the skin (lower central incisors in this image)
