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55 Cards in this Set
- Front
- Back
Asphyxia
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-Definition: Inadequate oxygenation of tissues
-Impedence to oxygenation is the primary pathological derangement -Leads to cerebral hypoxia, unconsciousness, death within minutes if not remedied |
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Mechanisms of Asphyxia
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-Suffocation
-Strangulation -Chemical -Drowning |
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Suffocation
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-Interference with the entrance of oxygenated air into lungs
- 4 types: smothering, choking, mechanical/traumatic/positional, environmental |
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Smothering
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-Obstruction of external airways (nose and mouth)
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Autopsy findings in a smothering
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-Possibly none
-Homicidal smothering look for teeth marks on inside of lips |
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Manner of death in a smothering
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-Accident: buried in a cave, baby smothered by bedding, overlay while co-sleeping
-Homicide: pillow over face, gagging, covering nose and mouth with duct tape -Suicide: plastic bag over head |
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Choking
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Obstruction/compression of internal airways (larynx & trachea)
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Manner of death in a choking
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-Accident: food or foreign body lodged in posterior pharynx
-Homicide: gag stuffed in mouth |
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Mechanical asphyxia
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Inability to expand chest
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Manner of death in a mechanical asphyxia
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-Accident: Car falls off jack onto chest, pinned by heavy object
-Homicide: burking (when someone sits on someone else's chest) |
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Environmental suffocation
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-Inadequate oxygen in the atmosphere
-Depletion of oxygen (enclosed space) -Naturally low oxygen concentration (cave) |
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Autopsy findings in an environmental suffocation
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Possible none
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Manner of death in an environmental suffocation
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Usually accident, e.g., child locked inside refrigerator
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Strangulation
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-Occlusion of blood vessels in the neck by external pressure
-Interferes with circulation -3 types: hanging, ligature strangulation, manual strangulation |
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Mechanism of death in a strangulation
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-Cerebral hypoxia due lack of oxygenated blood to the brain
-11 lbs of force necessary to occlude carotid arteries -Loss of consciousness in 10-15 seconds |
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Autopsy findings in a strangulation
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-Petechiae (scleral, conjunctival, facial)
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Hanging
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-Neck vessels occluded by weight of body causing constriction of noose around neck
-Does not require complete suspension, weight of head (10-12 lbs) |
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Autopsy findings in a hanging
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-Furrow
-Inverted V-configuration above larynx -Patterned imprint -Strap muscle hemorrhages -Pooling of blood in lower extremities and forearms, Tardieu spots on legs -Pale face |
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Manner of death in a hanging
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-Suicide-vast majority
-Accident-occasional (“choking” game, autoerotic asphyxia) -Homicide-rare |
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Autoerotic asphyxia
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Controlled hanging of short duration to reduce blood flow to brain resulting in transient cerebral hypoxia in order to increase pleasure of masturbation
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Scene of an autoerotic asphyxia
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-Nude
-Padded ligature to prevent abrasion -Escape mechanism -Pornography -Bondage material |
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Manner of death of an autoerotic asphyxia
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Accident
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Ligature strangulation
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Ligature tightened by other than body weight
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Autopsy findings of a ligature strangulation
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-Ligature mark
-Overlies or below larynx -Horizontal, since the body is not suspended and the noose will not be pulled up like in a hanging -Fracture of hyoid bone and/or thyroid cartilage |
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Manner of death in a ligature strangulation
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Most homicide, occasional accident, rare suicide
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Manual strangulation
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Pressure from hand, forearm, or other limb used to compress neck vessels
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Autopsy findings in a manual strangulation
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-Abrasions and contusions of skin of neck and undersurface of jaw
-Semicircular fingernail marks -Hemorrhage in neck muscles -Fracture of hyoid and/or thyroid cartilage with surrounding hemorrhage |
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Manner of death in a manual strangulation
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Most are homicides, suicide not possible (when you apply enough pressure to make you pass out, you release your hands and circulation will resume)
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Choking game
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-Strangulation game played by youth to achieve a “high-like” sensation without taking drugs
-In contrast to autoerotic asphyxia, not done for sexual gratification -Involves cutting off of circulation to carotid artery with a rope, belt, hands -Occurs alone or in groups -Accidental form of manual strangulation or hanging |
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Physical signs of choking game
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-Bloodshot eyes
-Unexplained marks/bruises on the neck -Small red dots around the face, eyelids, or the lining of the eyelids and eyes -Frequent, severe headaches -Disorientation after spending time alone |
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Indications at a scene that choking game was cause of death
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Unexplained presence of dog leashes, choke collars, bungee cords, ropes, scarves or belts tied to bedroom furniture or doorknobs or found knotted on the floor
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Chemical asphyxia
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-Gasses prevent utilization of oxygen at cellular level
-Carbon monoxide (accident, suicide) -Hydrogen cyanide (suicide) -Hydrogen sulfide (accident) |
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Drowning
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-Death from asphyxia within 24 hours of submersion in water/fluid
-Diagnosis of exclusion -3 types: salt water, fresh water, icy water |
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Near drowning
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-Survival of at least 24 hours after submersion in and aspiration of fluid
-Complications: pulmonary edema, cardiac arrhythmia, pneumonitis, sepsis, cerebral edema (edema occurs when an attempt is made to resuscitate you) |
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Mechanism of death in a drowning
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Airway submerged in water results in aspiration of water/fluid when person attempts to breathe, leads to impaired gas exchange, decreased oxygenation, hypoxic brain injury
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Diagnosis of exclusion
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-Drowning
-Non-specific findings -Need to rule out other causes of death by full autopsy and toxicology studies |
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Manner of death in a drowning
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Accident, suicide, homicide
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Salt water drowning
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-Decreases blood volume
-Salt draws plasma into alveoli by osmosis -Hemoconcentration, hypernatremia, pulmonary edema |
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Fresh water drowning
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-Increases blood volume
-Loss of surfactant causes alveolar collapse, pulmonary edema, hemodilution, hemolysis, circulatory overload, hyponatremia |
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Icy water drowning
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-Survival without neurological deficits possible after prolonged submersion
-Reflex bradycardia and vasoconstriction of all blood vessels except those supplying heart and brain |
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Autopsy findings of a drowning
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-Edema, frothy fluid throughout airway
-Water in stomach -Cerebral edema -Washerwoman hands- skin on hands and feet pale and wrinkled (occurs regardless of whether individual was alive or dead at time of submersion) -Diatoms (unicellular algae) in lungs or other organs, aspiration of fluid containing diatoms -Postmortem artifacts- scrapes on body from rough surfaces, animal/fish feeding activity, barnacles -Body decomposes twice as fast in water as in air -Time to rise to surface depends on temperature of water, body fat composition -Contributory factors: alcohol/drug intoxication |
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Environmental deaths
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Two types: hyperthermia and hypothermia
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Hyperthermia
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-Elevated core body temperature ≥105°F
-Types -Heat cramps -Heat exhaustion -Heat stroke |
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Heat stroke
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-Body’s normal heat-dissipating mechanisms incapable of compensating for increased environmental heat
-Life-threatening -Marked increase in core body temperature causes direct thermal tissue injury |
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Risk factors for heat strokes
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-Alcoholism
-Cardiac disease -TCA’s, MAOI -Obesity -Elderly, poor -Exertional – long distance runners, laborers, military recruits, football players |
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Symptoms of a heat stroke
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-Hyperthermia, hot dry skin, nausea, vomiting, muscle cramps, dyspnea, CNS dysfunction
-Vasodilation, circulatory collapse, cardiac failure -Complications: pneumonia, ATN, DIC, MI -Purkinje cell necrosis |
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Autopsy findings of a heat stroke
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-Non-specific
-Diagnosis based on antemortem history -Core body temperature -Environmental conditions |
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Manner of death in a heat stroke
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Accident
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Hypothermia
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-Core body temperature below 95°F
-Shivering, vasoconstriction, increased metabolism by brown fat (infants) -Causes paradoxical undressing: terminal hallucinations and feelings of warmth, so take off all clothes |
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Risk factors for hypothermia
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-Infant greater ratio of BSA to body mass, underdeveloped reflex centers
-Cold water immersion causes more rapid loss of heat that dry cold air because water dissipates heat from body much faster than air |
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Effects of hypothermia
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-Loss of ability to shiver
-Impaired cerebral function (reflexes) -Cold narcosis -v-fib, bradycardia |
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Autopsy findings in a hypothermia case
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-Cherry red lividity due to accumulation of oxyhemoglobin in tissues from underutilization (also seen carbon monoxide intoxication, cyanide poisoning, and refrigerated bodies)
-Hemorrhagic pancreatitis, focal ulcers of the gastrointestinal mucosa (Wischnevsky spots - picture) -Pneumonia, ATN, myocardial necrosis |
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Sexual assualt scene
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-Female
-Supine -Exposed breasts -Leg apart -Naked below the waist |
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Autopsy findings of a sexual assault
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-Bite marks on breasts
-Bruises on inner thighs -Vaginal/anal trauma (lacerations, contusions) -Semen deposits -Evidence of blunt trauma, strangulation |
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Evidence collection needed in a sexual assault
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-Swabs mouth, vagina, rectum
-Microscopic slides for sperm -DNA analysis -Acid phosphatase test for seminal fluid -Panties/underwear -Bite marks -Double swab for saliva/DNA (wet swab, dry swab) -Photograph |