Forensic Pathology

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Forensic Pathology

• - postmortem investigation of sudden or
  unexpected death or trauma to the living

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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. Accidental 4.
  Natural Causes
• D. Time of Death

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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)

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The Body Farm
1 acre of land owned by the University of
Tennessee
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Normal Postmortem Changes

• Algor mortis body cooling
• Rigor mortis body stiffening
• Livor mortis (lividity) blood settling
• Putrefaction destruction of body tissue by
  bacteria

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Algor mortis

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

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Algor mortis

• Body cools approx 1.5 degrees C/hr
• Skinny cools faster
• No clothes cools faster
• In water cools much faster
• normal tempmeasured temp/ 1.5 hrs

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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

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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

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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
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Livor Mortis

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

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

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Normal Postmortem Changes

1. Algor Mortis
2. Rigor mortis
3. Livor mortis
4. Putrefaction

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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

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Trauma to the Human Body
Role of the Pathologist

1. Determine type of wound
2. Measure the dimensions (length, width, depth)
3. Position relative to anatomical landmarks
4. Determine initial location if wound involves
   cutting, slashing, etc.
5. Determine height from heel

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Types of Wounds (Trauma)

1. Lacerations
2. Incised Wound
3. Puncture
4. Abrasion
5. Contusion
6. Gunshot

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Lacerations
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Incised Wounds
Slash
Stab
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Abrasions
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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.

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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

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Gunshot Wounds

• Things for pathologist to learn
• type of firearm
• distance of gun to victim
• entrance vs exit wounds
• track of projectile

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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
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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

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Close range

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

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Intermediate range

• Intermediate range
• 1-3 feet
• Gunpowder ball

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(No Transcript)
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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

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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

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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)