Forensic Pathology and Autopsy

1. Forensic Pathology and Autopsy

2. Pathology • Field of Medicine concerned with identifying disease • Forensic Pathology – subspecialty of pathology concerned with identification of human remains and determination of the cause and manner of death • The Field that performs an after death investigation of sudden or unexpected death or injury

3. What Do They See • Deaths with violence – accidents, suicides, homicides • Suspicious Deaths • Sudden, unexpected deaths, • Deaths without a physician in attendance • Deaths in a prison or jail

4. Goals • Identify: • Cause – The event/ injury that starts the process towards death • Manner - • Mechanism – the normal body function that results in death • Whether Time of death is consistent with proposed time

5. Definition of Death • Formerly not a problem • End of heart and/or lung function • No oxygen or blood = no life • Brain death • Individuals may be kept alive by artificial means through machines that breathe as lungs would or that pump as a heart would

6. Cause of Death • The process that starts the chain of events leading to death • Atherosclerosis  Heart Attack • GSW to Chest  infection of lungs • Car Accident  death during surgery 10 years later • Blunt Force injury to head  not swallowing correctly  Choke

7. Manner of Death • Natural • Accident • Suicide • Homicide • Undetermined

8. Natural Deaths • Atherosclerosis • Pneumonia • Cancer • Long term Alcohol/Drug abuse

9. Accident • Car Accident • Alcohol/ Drug overdose • Drowning • Suffocation

10. Homicide/Suicide • GSW • Stab Wound • Drug Overdose • Drowning • Car Accident • Asphyxia

11. Undetermined • Not enough information about circumstances surrounding death • Drug overdose – accidental overmedication or suicide • Cause of death unknown • Skeletonized remains • No anatomical or toxicological explanation

12. Scene investigation Medical and legal conclusions rely on thorough scene investigation • Identity • Approximate time of death • Evidence and clues to circumstances around death • Was the house locked? • Were there signs of struggle • Position of body • Suicide notes

13. Identification of remains • Visual by family/friends • Location of body – in their home? • ID – driver’s license, distinctive feature – tattoo • Comparing x-rays • Dental Records • DNA • Fingerprints

14. Mechanism of Death • The immediate activity that results in death. • Hemorrhage • Widespread infection • Heart Attack

15. Time of Death • Important for time of the murder, eliminate or suggest suspects, confirm or disprove alibi • Most methods are to a degree unreliable and inaccurate. • The longer the time between death and the attempt to estimate the time of death, the less precise the estimate of the interval

16. Estimation methods • Body temperature – 98.6 – rectal temp /1.5 • Insect action • Stomach contents – stage of digestion • Last known activity – newspaper/ mail, phone conversation/ text

17. Livor and Rigor • Livor Mortis is a reddish/ purple coloration due to accumulation of blood in the small vessels of the gravity dependent areas. • Occurs 30 min to 2 h after death • Fixed at 8-12 h • Important to determine position of body • Rigor – stiffening of the body due to disappearance of muscle energy • Usually appears 2-4h after death, fully develops 6-12 h after death • Classically • Jaw arms -> legs

19. Time of Death • Body Temperature • Time since death = (98.6°F – Rectal Temp) / 1.5 • Based on assumption body temp is normal at death • Decomposition (Decomp) • Breakdown of Cells and Organs by chemical process • Breakdown by bacteria and fermentation • Green discoloration of abdomen (24-36h) • Green spreads to head, neck and shoulders • Swelling of the face and abdomen due to gas formation • Marbling – breakdown of blood gives green/black color of blood vessels • Generalized bloating (60-72 h) • Skin slippage • Dry/ skeleton phase – 2 weeks in hot humid temps, months in snow

20. Entomology • Different insects are attracted at different stages after death • Flies are the most common form of insect associated with dead bodies • Lay eggs in orifices and open wounds • Eggs generally are deposited immediately after death in the day time • Only eggs on the body = 1-2 days • Maggots grow excessively larger in different stages each about 1 day • Adult flies emerge at 12 -18 days

22. External Exam • General Size and Appearance • Clothing /personal belongings • Major Injuries – cause of death signs • Medical Intervention • Signs of struggle – Frenulum, broken bones, scratches around the hands • Bruises, cuts, petechiae • Scars, tattoos • Livor, Rigor • Teeth, eyes, hair • Blood, eye fluid, urine

23. Trauma to the Human Body • Determine type of wound • Measure the dimensions (length, width, depth) • Position relative to anatomical landmarks • Determine initial location if wound involves cutting, slashing, etc. • Determine height fromheel

24. Types of Wounds • Lacerations • Incised Wound • Puncture • Abrasion • Contusion • Gunshot

25. Abrasions

26. Contusions • Color changes a bruise goes through can give rough estimate of time of injury • Dark blue/purple (1-18 hours) • Blue/brown (~1 to 2days) • Green (~ 2 to 3 days) • Yellow (~3 to 7 days) • Assumes person is healthy.

27. Gunshot Wounds • Things for pathologist to learn: • type of firearm • distance of gun to victim • entrance vs exit wounds • track of projectile

28. Gunshot Wounds Stippling – powder burns on the skin when the gun is inches to a few feet from the victim Starring of a contact wound – barrel touching the skin

29. Autopsy Y incision

30. Internal Exam • Y Shaped insicision • Remove Sternum • Exam any signs of injury internally (gunshot hole, stab wound) • Exam for signs of blood inside

32. Organs • Exam each organ, weigh them, cut them open, take pieces for microscope exam • Heart • Lungs • Kidneys • Liver • Spleen • Bladder • Brain

33. Natural Deaths • Heart Attack

43. Gunshot Wounds • Contact • Muzzle imprint, star-like cuts if close to bone, gunpowder and soot enter wound • Close Range • Increased diameter of soot of tattooing around wound • Particles of gunpowder around wound, soot on skin, tattooing of skin • Intermediate • Up to 3 feet • Increase in diameter again of particles and stippling, no soot • Long Range • No gunpowder, soot, tattoing • Difficult to determine distance –6 feet not different from 16 feet

44. GSW • Entrance Wounds • Usually smaller than exit wounds • May have star-like appearance • Inward beveling of skull • Ring of gunpowder and stippling • Exit wounds • Usually larger than entrance due to deflection by tissue • Outward beveling • No gunpowder, soot or skin injury

46. Asphyxia • Anything that interferes with oxygen uptake or utilization • Suffocation • Failure of oxygen to reach blood • Choking, drowning, carbon monoxide poisoing • Compression of chest – heavy objects • Strangulation • Usually cuts off blood supply to brain, not cutting off air.

47. Burns • Death due to smoke inhalation, incineration or infection • Establish – ID, whether the victim was alive at the time of fire • Cause of death • Manner of death • 75% of fire related deaths due to inhalation of toxic smoke – carbon monoxide, cyanide

48. Electrocution • Low voltage • Burns present at entry and exit sites • Death due to heart attack • High Voltage • Electrical burns • Charring • Death due to hearth attack or paralysis of breathing muscles

49. Blunt force injury to head • Brain Contusion – coup occurs at site of blow to head • Bleeding under skull and into brain • Tearing of arteries and veins that supply the brain • May kill immediately, or have slow growth of blood in the brain that compresses brain and prevents brain function

50. Car Accident • Patterned abrasions / bruises from steering wheel and seatbelt • Damage to liver and spleen