Forensics Flashcards
What happens when the heart stops beating?
Blood collects in the most dependent parts of the body, the body stiffens, and begins to cool
Define livor mortis, rigor mortis, and algor mortis
Livor mortis: blood collects in the most dependent parts of the body and becomes fixed
Rigor mortis: body stiffens
Algor mortis: body begins to cool
What is time since death if the body is warm and not stiff?
No longer than 3 hours
What is time since death if body is warm and stiff?
3-8 hours
What is time since death if body is cold and stiff?
8-36 hours
What is time since death if body is cold and not stiff?
More than 36 hours
Define putrefactive decomposition
Large accumulations of lipid fluids in body cavities, skin begins to slip. More common in warm climates. Mostly due to gut microbes, and the first thing seen is green discoloration in the RLQ of the abdomen.
What is adipocere formation?
Epidermis gets dissolved from being immersed in water. Lipid layer encases body.
What happens in mummification?
Happens in very hot and dry places or if the body falls into a peat bog.
What is the major focus of a forensic investigation?
Why did someone die- suddenly?
How did they die? Cause of death.
What is the manner of death? Opinion of medical examiner, accident, homocide, natural, suicide, undetermined. (NASHU)
Who can sign a death certificate of a natural death?
Licensed physician or coronor, or local jurisdiction
Who can sign a death certificate in unnatural causes of death?
A forensic pathologist/medical examiner
How do you determine cause of death?
Comes from the autopsy. The underlying cause of death refers to the disease or injury that initiated the train of morbid events leading directly to death or the circumstances of the accident or violence that produced the injury.
Ex: cardiorespiratory arrest is never a cause of death, is a description of death
What is the focus of forensic examination?
Is it a natural death or consider circumstances in terms of the probability of foul play/unnatural death, or contributions thereof
Why are there so few hospital autopsies?
Most hospitals have 5% or less autopsy rate. Used to be much higher. Fewer now because we don’t want an unknown undiagnosed disease to be discovered and get sued. Everyone can be sued except the medical examiner.
Also time consuming and expensive.
The ME has no duty to families, so who does he/she work for?
“Works for society”. Family plays very little role in decision-making. MEs have sovereign immunity, can’t be sued in their office.
If a case appears “obvious”, why do a forensic autopsy?
If no autopsy is done then you can’t refute other claims. It’s good to know if there was an underlying cause.
What are the types of mechanical force injuries?
Blunt force
Incise wounds
Gunshot wounds
What are the types of blunt force trauma?
Abrasions
Lacerations
Contusions
What is an abrasion?
A wound in which (primarily) the epidermis is injured. It is produced by friction scraping away epidermis or crushing of the epidermis by direct pressure or a blow tangential to the surface.
An abrasion oozes serum or blood (but does not tend to bleed profusely) and generally heals by formation of a scab.
What are the types of abrasions?
Brush abrasion
Impact abrasion
Patterned abrasion
What is a brush abrasion?
Produced by grazing or sliding motions (the applied force is tangential to the body surface).
Close inspection reveals “rolls” or “heaps” of tissue at the margin of the wound opposite the direction of force. Large confluent scrapes are known as “brush burn” or gliding abrasions.
What is a patterned abrasion?
Occurs when the abrasion looks like the surface appearance of the object.
What is most susceptible to ionizing radiation injury?
Lymphocytes, bone marrow. Formed elements of the blood.
Define lacerations
Always blunt force trauma. Irregular tear in the skin or other organ.
Why should you care about forensic information/evaluation and some level of training?
Understand concept of certification of death.
What is a contusion?
A bruise and it results from hemorrhage into soft tissue due to rupture of subcutaneous blood vessels by blunt force injury.
The epidermis is intact and the wound does not bleed externally. Can be seen on the skin or in deep viscera.
What does the severity of contusions depend on?
Amount of force applied
Vascularity of the tissue
Type of tissue injured, with loose tissue injured more
Location of the tissue with tissue over bone more easily bruised
What do the colors of the contusion mean, including yellow, blue, purple, and brown?
Yellow- most significant color and its presence indicates that the bruise is at 18 hours or older.
Blue, purple and red do not assist in dating bruises.
Brown is a mixture of colors and therefore is not useful.
What are incise wounds? How is it different from a puncture wound.
Happens when there is a puncture injury that goes deeper than it is longer. Can be from scalpels (during surgery).
Made by a sharp object and is longer than a puncture, which has a rounded outline and is deeper than it is wide.
Is it conceivable and possible to legitimately have a death certificate state COD unknown and MOD undetermined?
Yes
Can you put cardiorespiratory arrest as COD?
NO
Define stabbing instruments. What re the most common? Single edged blade vs double edged blade?
Any sharp instrument capable of overcoming the tensile strength of the skin. Although knives are the most commonly used weapon in sharp force injury, other implements such as scissors, screwdrivers, bbq forks, and kitchen forks.
Single edged blade will make a triangle shaped incision. Double edged blade will make more of a rounded diamond injury.
Is SCIDS Accident, suicide, homocide, or undetermined?
Considered natural manner of death
Compare GSWs from long guns vs bigger bullets
Long guns fire with more velocity and velocity causes more damage than a bigger bullet. Bigger bullets often go faster.
Low velocity= small entry, no exit (or small exit)
High velocity= relatively small entry, big exit
Describe GSWs to the head/skull, compare to other entry wounds.
The adult skull has an inner and outer table separated by the diploe. In GSW the outer table of the skull is typically sharply circumscribed and the inner table beveled.
If the round exits, the opposite is seen. Beveling of external wound.
What kind of death is lethal injection?
Homicide
Is forensic definition of laceration include incise wounds?
No, from blunt force
What is the wounding formula for blunt force?
W=E x 1/T x 1/A x K
Inversely related to time and area.
Shorter period of time, more wounding.
What happens in the skull with fractures from blunt force and previous fracture lines?
Fractures emanating from blunt force or sometimes GSWs do not ramify across previous fracture lines (stop rather than cross them). You can thus ascribe a number to wounds and determine their timing with some accuracy.
This is different from other areas of the body where it can be very difficult to assess the timing of wounds.
Define contact wounds for GSWs
Dirt, powder grains, and soot in the depths of the wound. Marginal abrasion.
Define intermediate wounds for GSWs
Stippling and powder tattooing pattern, powder that burns into the skin. Marginal abrasion.
Define distant wounds for GSWs
No tattooing pattern, no soot or powder in the depths of the wound. Marginal abrasian.
Compare cause of death vs. mechanism of death for GSW
Mechanism of death is hemorrhage (immediate), cause of death (proximate) is the gunshot
What can be seen in driver of vehicle in MVA?
Dicing injuries on left side of face
How might an ice pick wound appear?
As a small caliber firearm or shotgun pellet wound.
Salient wounding formula for GSWs?
KE=1/2m x V^2
Most important is velocity
Why are hollow point bullets preferred for police?
Less likely to go through the body and hit someone else
Are contact GSWs often seen in homicides?
No, think suicide
What is the approach to mass disasters at the macro level?
The scene: Safeguarding Surveying Documenting Proper approach to specimen retrieval
What is the approach to mass disasters at the micro level
Biologic materials retrieval and transmittal vs. inorganic specimens/substances
