Autopsy/Forensics Flashcards
What are “fouling” and “stippling”?
Fouling and stippling are terms used to describe the types of gunshot residue in close and intermediate range gunshot wounds. Fouling is the dust-like burnt powder grains that can be wiped off the body. Stippling (or tattooing) is from the unburnt powder striking the skin and causing a superficial injury. Stippling usually appears as numerous pinpoint injuries, and it cannot be wiped off.
Which can be wiped off the body, fouling or stippling?
Fouling and stippling are terms used to describe the types of gunshot residue in close and intermediate range gunshot wounds. Fouling can be wiped off, and stippling cannot.
A gunshot wound is classified as close range when there is fouling and stippling. Typically for a handgun, close range is within about (distance). Beyond that distance, the fouling will not reach the body but the stippling will. These wounds are classified as intermediate range.
A gunshot wound is classified as close range when there is fouling and stippling. Typically for a handgun, close range is within about 6” (15 cm). Beyond that distance, the fouling will not reach the body but the stippling will. These wounds are classified as intermediate range. If no fouling or stippling is observed, the term distant gunshot wound is used.
The wounding pattern produced by a shotgun will depend greatly on the range of fire. Under (distance), birdshot will cause a single round entrance wound that is 3/4 to 1” (1.5-2.5 cm) in diameter (regardless of the gauge of the shotgun). By a range of (distance), there will be a cookie-cutter pattern with scalloped margins as the pellets start to spread apart. At (distance), there are satellite wounds.
The wounding pattern produced by a shotgun will depend greatly on the range of fire. Under 2 feet, birdshot will cause a single round entrance wound that is 3/4 to 1” (1.5-2.5 cm) in diameter (regardless of the gauge of the shotgun). By a range of 2-3 feet (60 cm to 1 m), there will be a cookie-cutter pattern with scalloped margins as the pellets start to spread apart. At 4 feet (1.3 m), there are satellite wounds.
How accurate is estimating the range of fire of a shotgun based upon a radiograph of the pellets?
Not accurate; do not attempt. Due to the billard ball effect, shot will spread widely inside the body even though it may have entered the body through a single defect.
What is the classic location for trochar insertion for embalming?
Just superior and lateral to the umbilicus. And remember that diagnostic peritoneal lavage is usually done with a small midline incision.
By definition, a laceration is an injury due to ___.
By definition, a laceration is an injury due to blunt impact. The term is commonly misused in medicine to denote any skin injury that needs to be sutured. Sharp injuries (cuts, stabs) are not lacerations.
What type of wound may have features of both sharp and blunt injuries?
Chop wounds (such as from a hatchet).
What are the 3 types of blunt injuries?
Lacerations, contusions, and abrasions.
When a moving head impacts against a firm surface, the brain contusions are located (beneath/opposite) the point of impact. When a resting head is struck with an object, the contusions are located (beneath/opposite) the point of impact.
When a moving head impacts against a firm surface, the brain contusions are located opposite the point of impact. When a resting head is struck with an object, the contusions are located beneath the point of impact.
The dura is especially adherent to the inner calvaria in what ages?
The elderly and infants. This is why epidural hemorrhages are uncommon in these groups.
Why can blood from an epidural hemorrhage provide valuable toxicology information?
The epidural blood may contain valuable toxicology information particularly if the person survives for some time after the injury. Since it is relatively sequestered, the toxicology findings may best represent the state of intoxication at the time of injury as opposed to blood collected at autopsy which would have undergone normal metabolism during the interval of survival.
In intrauterine fetal death, how soon can maceration be seen?
Maceration may be seen at delivery in as early as 6 hours and almost always by 12 hours.
What are the half-lives of carbon monoxide in room air and in 100% oxygen?
Room air: 4-6 hours. 100% oxygen: ~1 hour.
Does heat cause epidural or subdural hematoma?
Heat can cause artifactual epidural hemorrhage but not subdural hemorrhage. A subdural hematoma found in a burned body occured before death.
What is the voltage threshold for low-voltage electrocution vs. high-voltage electrocution?
1000 V.
Do low-voltage and high-voltage electrocutions leave burns on the body?
Most high-voltage electrocutions will leave burns, but fewer than half of low-voltage electrocutions will leave burns.
Although the rate of rigor mortis is affected by various intrinsic and extrinsic factors, what is the general rule for the rate of progression?
Rigor mortis occurs gradually over several hours and usually reaches a peak (“full rigor”) in about 12 hours. Several hours later it will start gradually to disappear over the following 12 hours.
Although the rate of algor mortis is affected by various intrinsic and extrinsic factors, what is the general rule for the rate of progression?
Body temperature usually cools at a rate of 1-2 F per hour.
What percent of drownings will have “dry” lungs?
10-20%.
Hypothermia is defined as a core temperature of less than ___.
Hypothermia is defined as a core temperature of less than 95 F (35 C).
True or false: Most people with alcoholic cardiomyopathy have cirrhosis.
False.
How is serum ethanol level converted to BAC?
To convert serum ethanol level to BAC, move the decimal point 3 places to the left. Example, a 100 mg/dL serum ethanol level is equivalent to a 0.10 (g/dL) BAC, or 0.10% (weight/volume). This means that one tenth of a percent of a person’s blood volume is alcohol or that a person has 1 part alcohol per 1000 parts blood.