Autopsy: forensics I

coup

brain injury at the site of impact

countercoup

• brain injury opposite the site of impact

• larger

  • common in MVA

1. number

2. location

3. distribution

4. presence of satellite injuries

5. characteristics: length, shape, orientation, appearance of margins, marginal or adjacent abrasion, depth and structures injured, direction of wound track

6. clothing defects

List the important factors to document for stab wound injuries (6)

• circular defect with marginal abrasion

• inverted margins

• soot and stippling

entrance wounds

• irregular defect whose edges can be re-approximated

• stellate, beveled, slit, crescent

• everted margins

• no marginal abrasion, but can be shored (collar of abrasion)

exit wound

entry wound

exit wound

• congestive and heavy lungs

• little food in GI tract

• distended and full bladder

• sedation

• foam cone

• drug users: track marks, skin popping

• cocaine = MI with no other risk factors

list potential autopsy findings in overdoses cases as discussed in lecture. ​

scratch

• abrasion caused by sharp object passed across the skin

• heaping of surface layers in front of the object leaves clean area at the start and tags at the end

• e.g. fingernails, thorn, pin

graze

abrasion that occurs when there is movement between the skin and some rough surface (e.g. road rage)

impact abrasion

abrasion with more force and less duration

pressure abrasion

abrasion caused by crushing of superficial layers of skin; associated with bruise of surrounding area; force less, duration more

patterned abrasion

post mortem insect bites can mimic

contusion

bruises due to rupture of vessels, usually capillaries; no loss of continuity of skin

pulmonary contusion

caused by extreme chest trauma; excess fluid interferes with gas exchange leading to hypoxia (e.g. explosions, traffic accidents, falls, sport injuries, falls)

basilar skull fracture

battle’s sign behind ear and raccoon/panda eyes indicate?

laceration

irregular edges, hair bulbs crushed, less hemorrhage, wound bridging, varying depth

split laceration

occurs by crushing of the skin between two hard objects

stretch laceration

common in high velocity intraoral GSW

avulsion

degloving accidents

tearing laceration

ripping of skin and tissue from impact by or against object

compound

fracture in which bone protrudes through skin

incised wound

• clean, cut edges, well-defined, free from contusions

• spindle-shaped

• lots of hemorrhage from clean cut vessels

• deeper at the beginning and more shallow at the end (“tailing”)

defensive wound

• grasping surfaces of hands - flap wound created

• ulnar border of forearm

• dorsum or plantar surface of hand

• lower limbs - sexual assault

stab wound

• depth > length

• width of wound < width of weapon - stretching of skin

• clean cut edges

• punctures around concealed parts of the body (axilla, vagina, rectum, nostrils)

1. abrasion

2. contusion

3. laceration

4. fracture

4 types of blunt force trauma

1. removing the tension caused by the elastic fibers in the skin is necessary to evaluate the true shape

2. isolating the area by cutting it from the surrounding skin and subcutis or with transparent tape

describe the procedure necessary to evaluate the true shape of a stab wound

contact gunshot wound

• circular and smaller

• stellate over scalp

• burning /blackening of immediate wound edges

• soot within tissues

• muzzle mark

• inverted wound margins

• back spatter = blood sucked up into the barrel of the weapon

close range gunshot wound

• almost always circular

• inverted edges

• collar of abrasion

• burning effects

• tattooing/stippling

medium/distant range gunshot wound

• from less than 0.5 meters to several kilometers away

• abrasion collar around entry wound

• wound is inverted

• ring of dirt or grease ring

• bullet striking sideways – may produce rectangular lacerated wound 

tangential gunshot wound

tears with skin tag formation

short range shotgun wound

• 6 inches – 6 feet

• soot soiling vanishes after 1 foot

• tattooing

• single wound

• rat hole injury

• separate wad injury as an abrasion or bruise

distant range shotgun wound

• >6 feet

• no soot

• number of separate pellet holes increase progressively around main wound

• wad often takes lower trajectory

• 6-10 meters, central hole may shrink to nothing

1. suffocation

2. strangulation

3. chemical asphyxia

three types of asphyxial deaths

smothering

suffocation due to mechanical obstruction of the nose and mouth

choking

suffocation due to obstruction of airway; no petechiae

mechanical suffocation

• pressure on chest and abdomen making it impossible to breath; most accidents

• face and neck are deep purple from congestion; petechiae of conjunctiva and sclera, confluent scleral hemorrhage

strangulation

1. occlusion of BV in neck secondary to external pressure

2. mechanism of death = cerebral hypoxia secondary to obstruction of vessels bringing oxygenated blood to the brain

3. NOT due to compression of the trachea

4. cyanosis, petechial hemorrhages of conjunctiva, sclera and periorbital skin

hanging

1. type of strangulation

2. usually pale face, protruding tongue and dried out mucus drips from nose with no petechiae depending on the degree 

3. tardieu spots on heart and pooling of blood in the LE and forearms

4. furrow in neck

5. may see sclera or conjunctival hemorrhage/strap muscle hemorrhage/hyoid bone or thyroid cartilage fracture but not always

ligature strangulation

• pressure on neck applied by object tightened by force other than body weight

• most commonly associated with rape

• death due to occlusion of carotid arteries with cerebral hypoxia

• blood gets to head but can’t drain = congested face, numerous petechiae of sclera and conjunctiva, periorbital and face skin too

manual strangulation

1. strangulation from hand, forearm or another limb; occludes vessels on neck

2. congestion of face, petechial hemorrhages, fingernail marks, hemorrhage in the strap muscles, hyoid fracture, abrasions/contusions on neck

3. can’t say antemortem if no significant hemorrhage around hyoid/thyroid

chemical asphyxia

• gases that prevent utilization of oxygen at the cellular level

• carbon monoxide most common

• helium, hydrogen cyanide, hydrogen sulfide

cyanide poisoning

• bitter almond scent

• tox - 200 mg lethal

• internal organs = bright pink

• damage, blood-stainined stomach lining

hydrogen sulfide

• green discoloration of brain

• exposure by proximity to waste water treatment facilities, landfills and farms with manure storage

• supine, naked, spread, legs

• bite marks and bruising - breasts, inner thighs

  • double swab method for bites! (wet then dry swab)

• trauma to vagina/anus

  • contusions in posterior 5-7 o’clock

• semen deposits - UV light (don’t need sperm to prove)

• common COD - strangulation, BFT, stabbing

• swabs of mouth, rectum, and vagina

• fingernails

describe potential autopsy findings in a sexual assault/rape case as presented in lecture.

objectivity - based on facts and not personal opinions or other influences

internalize the importance of upholding professional ethical standards when arriving at a manner of death, as discussed in class

contact

what distance?

contact

what distance?

contact

what distance?

close range

what distance?

close range

what distance?

medium range

what distance?

medium range

what distance?

tangential

what distance?

contact

what distance?

near contact

short range

what distance?