Forensic Death Investigation Flashcards
(26 cards)
What are the purposes of forensic death investigation?
- To identify the deceased
- To establish the cause of death
- To determine the manner of death
- To investigate the circumstances surrounding the death
What are the common disciplines in forensic death investigation?
Forensic pathology
* Observation and autopsy to determine cause and manner of death
Forensic toxicology
* Analyzes biological samples for drugs, alcohol, and toxins that may have contributed to COD
Forensic anthropology
* Studies human skeletal remails to identify individuals and determine COD
Forensic entomology
* Uses insects found on decomposing bodies to estimate TOD
Forensic odontology
* Uses dental growth or records to indentify individuals or estimate TOD
What are the differences between a coroner and medical examiner?
Coroner:
* Official, often elected positon
* Investigates death
* Does not need medical training
* Determines COD, oversees legal inquiries into death, and issues death certificates
Medical examiner:
* Medically qualified -> usually a physician
* Investigates death
* Has specialized training in forensic pathology
* Determines COD, conducts autopsies, issues death certificates, collects medical evidence
What are cause of death (COD), mechanism of death, and manner of death?
Cause of death
* Anything that produces a physiological derangement in the body that results in death
* Gunshot wound to the head
* Stab wound to the chest
* Cardiovascular disease
Mechanism of death
* The physiological derangement produced by the cause of death that results in death
* Hemorrhage
* Septicemia
* Cardiac arrhythmia
Manner of death
* How the cause of death came about
* Natural
* Homicide
* Suicide
* Accident
* Undetermined
What is the autopsy procedure?
External examination (1st)
* fingerprinting
* height/weight
* photopgraphy
* UV exam
* collect evidence
Internal examination (2nd)
* head (circular saw)
* chest (y incision)
* abdomen
* collect evidence
What is the postmortem clock?
Following death, numerous changes occur provide a sequence of
events that may allow the forensic pathology to estimate time since
death
What are the classfications of postmortem intervals (PMI)?
Immediate PMI (0-2 hours)
* Rapid biochemical and physiological changes
* Caused by the absence of circulation of blood and loss of regulatory mechanisms
Early PMI (0-72 hours)
* Most important time period for PMI investigation
* Classical triad of post-mortem changes—rigor mortis, livor mortis, and algor mortis
Late PMI (1-years)
* Primarily describable as decomposition or putrefaction
What is rigor mortis?
- The stiffening of the muscles after death
- No more oxygen = no more ATP = no ability for muscles to relax
- Can start right after death (usually appears 2-4 hours postmortem)
- Disappears anywhere from 24 to 48 hours after appearance
What is livor mortis?
- Settling of blood after death
- Blood pooling in the lowest part of the body (due to gravity)
- Develops immediately after death
- Fixed 6-12 hours (red spots on body will stop moving)
*
What is algor mortis?
- Decline in body temperature due to heat loss from the body
- Loss of homeostatic regulation by the hypothalamus
- Most accurate method of estimating time since death in early post-mortem phase
- Body cools 1.5F every hour
What are the stages of human decomposition?
- Fresh stage
- Bloat state
- active decay stage
- advanced decay stage
- skeletal stage
What happens during the fresh stage?
Livor, algor, and rigor mortis
What is the bloat stage
- Bloating of the body cavity
- Color change of tissue
- Plie position (leg positon)
- skin slippage
- Marbling
- Maggots
Mechanism:
* Bloating happens from the rapid growth and spread of bacteria
* Gases and liquids increase and build up pressure
What are the active and advanced decay stages?
- Cadaver decomposition island (liquid around body)
- Collapse of body cavity
- Desiccation of body tissye
Mechanism:
* Fluids are released from the body, and the body loses fluid via evaloration in dry or moist environments
What is the skeletonization stage?
- 50% of the skeleton is exposed
- Soft tissue can still be present
- This stage is usually present 2-9 months post-mortem
What are the bones we are required to know?
Adults have 206 bones, Kids have 270-300 bones
- Skull
- Humerus
- Coccyx (middle of pelvis)
- Pubis (Edge of side of pelvis)
- Femur
- Tibia (thick inside bone)
- Fibula (thinner outside bone)
What are appositional and longitudinal growth?
Appositional = growth in width of bone
Longitudinal = growth in length of bone
What are the questions of forensic anthropologists?
- Are the remains human or animal
- What is the race of the individual?
- What is the sex of the individual?
- What is the age of the individual?
- What is the stature of the individual?
What is the best bone to indicate sex?
Pelvis (90-05% accuracy)
What is the best area for examining ancestry?
The nose:
* Black: Root and opening in skull face is wider, aperture is rough, equilateral triangle
* White: Narrow, isosceles triangle
* Asian: In the middle
What are the best ways to estimate age in children and adults?
Children: Dental development
Adults: Long bones
What are the two ways to use bugs to estimate PMI?
Growth stage and insect succession
What are the orders of important insects in forensic science?
Order Diptera
* Flies and mosquitos
* First to arrive
* Larvae: maggots
Order Coleoptera
* Beetles
* Largest order
* Usually come after flies
What are the two key species of blowflies?
Chrysomya rufifacies (hairy maggot blowfly):
* Common in the Southern US
* Larvae and predatory and cannibalistic
Calliphora vicina (European bluebottle fly):
* More abundant in cooler climates
* Adults have metallic blue abdomen and bristly body
