Lecture 12 and 13 - Forensic Pathology Flashcards
Definition of pathology?
A medical specialty focused on how disease and injuries impact the body
What are the 2 categories of pathology?
- Anatomical
- Clinical
What are the 5 specialties in anatomical pathology?
- Surgical
- Cytology
- Neuro
- Pediatric
- Autopsy/Forensics
What are the 3 specialties in clinical pathology?
- Haematopathology
- Microbiology
- Biochemistry
Definition of forensic pathology?
A medical specialty in which the study of how diseases and injuries impact the body is applied to the law
What do forensic pathologists do?
- Go to scenes
- Perform autopsies
- Testify in court
Autopsy facts: unexpected/violent deaths, 150/year, 10-20% suspicous
How do you become a forensic pathlogist in NZ?
- Medical school (6 years)
- Anatomical pathology + forensics
or - Forensic pathology (6 years)
Total of 12 years
What is the difference between homicide and murder?
- Homicide = death at the hands of someone else (medical term)
- Murder = can legally charge someone with murder
What is the death investigation system for a medical examiner (M.E)?
- Investigation done by specially trained investigators
- M.E = forensic pathologist
- M.E makes autopsy decisions and performs autopsies
- Death certificate signed by M.E
- Inquiries initiated by Chief
- Patnership with other agencies
What is the death investigation system for a coroner?
- Investigations done by police or investigators
- Coroners = depends on jurisdiction
- Coroner makes autopsy decisions
- Pathologist does the autopsy
- COD/MOD determined by coroner regardless of autopsy results
- Death certificates signed by coroner
- Hold coroner’s inquest
What is the death investigation process in NZ?
- Coroner system (coroner are lawyers, no medical training required)
- Deaths investigated by police (no special training, Criminal Investigation Branch (CIB) involved with suspicious deaths)
- Autopsies doen by anatomical and forensic pathologists (suspicious deaths and homicides require a forensic pathologist)
What is the New Zealand coroner system?
- Police investigates death, preliminary report supplied to coroner
- Coroner decides whether an autopsy is required, direction is sent to pathologist
- Pathologist performs autopsy, preliminary cause of death sent to coroner
- Pathologist orders and interperates ancillary tests, final autopsy report sent to coroner
- Coroner reviews all information and determines cause and manner of death
- If necessary, a coroner’s inquest is conducted into the death
What kinds of deaths become coroner cases?
- Unnatural or violent deaths
- Unexpected deaths
- Unattended deaths
- Death in custody (any time police are present)
- Deaths in institutions
- Deaths during or immediately following surgery/anasthesia
Who gets an autopsy?
All homicides and suspicious deaths
Who gets an autopsy from a pathologists perspective?
- Unexpected childs deaths
- Bodies found in water
- Most apparent suicides
- Motor vehicle accidents
- Apparent drug related deaths
- Workplace related deaths
- Deaths in custody
What is an autopsy?
- Review of history
- External exam
- Internal exam
What other tests do pathologists use to determine what happend to a body?
- Radiology
- Microscopy
- Toxicology
- Microbiology
- Neuropathology
- Genetics
During an autopsy, what is looked at during an external exam of the body?
- Hair and eye colour
- Teeth
- Tattoos
- Scars
- Post-mortem changes (lividity, rigor, decomposition)
- Injuries
- Clues to cause of death
What is lividity?
- Setting of blood due to gravity
- Becomes fixed over a variable amount of time (typically 21 hours)
What information does lividity provide?
- Time of death
- Position at death
- Whether the body was moved
- Possible cause of death (e.g. cherry red lividity = CO, Cyanide, Hypothermia)
What is rigor?
- Stiffening of muscles (mucsles need energy to relax, max at 12 hours, gone between 24-48 hours)
What information does rigor provide?
- Time since death
- Whether the body was moved
What is the decomposition process (in terms of a pathologist)
- Autolysis (intracellular enzymes)
- Putrefaction (bacteria)
- Skeletonization
- Mummification (dry, warm environment)
- Saponification (adipocere, cold, wet environment)
What is seen during the process of decompositon?
- Green discolouration of abdomen (most bacteria here)
- Marbling (breaking down of blood cells)
- Skin blebbing and marbling (blisters and bloating)
- Insect activity (maggots etc)
- Skeletonization
- Mummification
- Adipocere
What is adipocere?
- Tissues turn into fatty acids
- Grey/white wax substance (“grave wax”)
How are post mortem changes speed up?
Environmental factors
- Increased temperature of the body at death
- Thick clothing
- Intense activity just prior to death (e.g. seizure, exercise)
- Obesity
- Higher ambient temperatures
How are post mortem changes slowed down?
- Hypothermia
- Emaciation
- Cold environment
During an autopsy, what happens during an internal examination?
- All organs removed and examined
- Samples collected (toxicology, microscopy)
- Special dissections as needed (neck, spinal cord, injuries)
Why is the incision made during an internal autopsy a Y shape?
So can be hidden with clothes on for families and funerals
What are pathologists looking for during an internal examination?
- Haemorrhage
- Tumour
- Infarcts
- Other signs of natural diseases
Examine all organs
What can an autopsy tell us?
- Cause and manner of death
- ID of victim
- Types of injuries/weapons used
- Perpetrator
- Timeline
- Time since death
- Mens rea (intentional)
- Genetic diseases that may affect familiy members
- Disease and injury prevalence and patterns
- New public health concerns
- Quality assurance and feedback on medical procedures
What are some injuries that pathologists look at?
- Blunt force
- Sharp force
- Firearms
- Thermal
- Environmental
- Electrocution
- Asphyxia
What are considered as blunt trauma?
- Abrasions
- Contusions
- Lacerations
- Fractures
What is an abrasion?
Scraping of the skin surface (scratches and scrapes)
What is contusions?
Breaking of blood vessles with leakage of blood into surrounding tissue (bruising)
What is laceration?
Tearing of the skin or an organ from a blunt impact
What are the properties of a cut/stab?
Sharp force
- Straight edges
- Clean edges
- Abrasions less common
What are the properties of a laceration?
Blunt force
- Irregular edges
- Tissue bridging
- Abrasion common
What can gunshot wounds tell pathologists?
- Entrance vs exit (direction of fire)
- Range of fire
- Type of firearm
What are the properties of an entrance of a gunshot wound?
- Usually round/oval
- Abrasion margin
- May have a muzzle imprint (contact)
- May have soot (close)
- May have stippling (intermediate)
- Internal beveling of skull
What are the properties of an exit of a gunshot wound?
- Usually star shaped or linear
- Fully re-opposable
- No soot
- No stippling
- No muzzle imprint
- External beveling of skull
What is stippling?
- Caused by unburnt gunpowder striking the skin
- “tattooing”
- Intermediate range
What is asphyxia?
- Neck compression
- Airway obstructed
- Mechanical asphyxiation
- Exclusion of oxygen
What is mechanical asphyxia?
Physical force preventing breathing e.g. car crushing lungs
What is Mens Rea?
Guilty mind = intention
