Forensic Pathology

1. Forensic Pathology - postmortem investigation of sudden or unexpected death or trauma to the living

2. Role of the Forensic Pathologist • 4 broad determinations to be made: • Cause of Death – medical diagnosis (the injury) • Mechanism of Death –how the injury produced death (arrhythmia, exsanguination) • Manner of Death • 1. Homicide 2. Suicide 3. Accidental4. Natural Causes • D. Time of Death

3. Time of Death • Can estimate time of death from • body changes • estimate: [98.6 oF – rectal temp]/1.5 • insect action (forensic entomology) • stomach contents (stage of digestion) • last known activity (last sighting, newspaper/mail)

4. The Body Farm 1 acre of land owned by the University of Tennessee

5. Normal Postmortem Changes • Algor mortis: body cooling • Rigor mortis: body stiffening • Livor mortis: (lividity) blood settling • Putrefaction: destruction of body tissue by bacteria

6. Algor mortis • Cooling of the body after death. • Best indicator of TOD in 1st 24 hrs • Taken: • Rectal • Liver

7. Algor mortis • Body cools approx 1.5 degrees C/hr • Skinny cools faster • No clothes cools faster • In water cools much faster • normal temp–measured temp/ 1.5 = # hrs

8. Rigor Mortis • Rigor: stiffening of muscles due to build up of salts. • Begins: 12 hours post mortem • face, arms, abdomen, legs • Takes: 12 hours to get fully stiffened • Then starts to go away in same order • Face, arms, abdomen, legs

9. Rigor • Begins: 12 hours post mortem • face, arms, abdomen, legs • Takes: 12 hours to get fully stiffened • Then starts to go away in same order • Face, arms, abdomen, legs

10. Rigor Mortis Body warm not stiff less than 3 hours Body warm stiff 3-8 hours Body cool stiff 8-36 hours Body cool not stiff more than 36 hours

11. Livor Mortis • Lividity: red/purple coloration of skin. • Due to settling of blood after death • Skin will appear white in areas that were compressed.

12. Lividity will appear in about 2 hours. • Areas will turn white if you press • Lividity will be “set” after 5 hours

13. Normal Postmortem Changes • Algor Mortis • Rigor mortis • Livor mortis • Putrefaction

14. Decomposition • 2 days post mortem • Marbling neck and shoulders • 1st red then green • From bacteria getting into subQ tissue • bloating from gases created by bact. • Organs decompose in order: • Stomach and intestines, heart and liver • Musculature

15. Trauma to the Human Body Role of the Pathologist • 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

16. Types of Wounds (Trauma) • Lacerations • Incised Wound • Puncture • Abrasion • Contusion • Gunshot

17. Lacerations

18. Incised Wounds Slash Stab

19. Abrasions

20. 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.

21. Stab Wounds • Laceration is a tearing injury due to friction or impact with a blunt object. • Puncture is a penetrating injury due to pointed object without a blade, such as an ice pick • Serrated blades produce the same smooth edges as nonserrated blades. • Abrasion is a friction injury removing superficial layers of skin, • Contusion is a bruise due to rupture of small blood vessels. • Slash wounds tend to look like bullet wounds that only graze the surface of the skin. Other types of slash wounds are called "hesitation marks" commonly found in suicide cases. They are typically rectangular in shape; i.e., their cuts are as wide and they are long. • Incision wounds: cutting with a blade, always have lengths greater than their depth

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

23. 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

24. Gunshot wounds • Contact Wound: Muzzle applied to skin at shooting. • Impression of muzzle burned around entrance wound • Close Range (6-8 inches): Stippling • Intermediate Range (1- 3 ft.): hot fragments of burning gunpowder; “ball” • Distant (greater than 3 ft.): No soot or burning of wound margins • Entrance wound: surrounding skin dragged in • Exit wound: skin pushed out

25. Close range • Close Range • (6-8 inches): Entrance surrounded by stippling- HOT soot traveling for short distance; BURNS

26. Intermediate range • Intermediate range • 1-3 feet • Gunpowder “ball”

28. POISONING • Determined by discolorations on body • Cherry- red lividity is sign of carbon monoxide poisoning • Toxins give off unusual odors • Certainty of diagnosis requires toxicological confirmation • Samples taken of stomach, vomit, kidney, lungs, liver

29. BURN • Scorching or burning of skin leads to sepsis and is immediate cause of death • Wounds caused by heat, chemicals, or electricity • Fire victims found in “pugilistic” position: clenched fists, resembling pose of boxer • Heat causes protein in body to contract • Blood and lung samples taken

30. Blunt force trauma • Blunt Force trauma results from clubbing, kicking, or hitting the victims. • The blow produces a crushing effect on the human body, resulting in contusions, abrasions, lacerations, fractures, or rupture of vital organs. • Red-blue contusions are always present, but this varies by the weight of the individual (obese people bruise easier than lean people)