Forensic Pathology Flashcards
Rigor mortis
Usually occurs approx 24-48 hrs uniformly.
After rigor mortis, a period of secondary flaccidity occurs.
Algor mortis
Change in body temperature to reach room temperature.
Livor mortis
Pooling of blood post mortem. Can be either fixed or unfixed.
Putrefactive decomposition
Occurs when exposed to air and moisture. Bacteria decompose the body. Bacteria at the cecum are usually first to invade.
Adipocere decomposition
Occurs in bodies submerged in water. Hydrolysis of lipids allows for a wax-like covering of the body.
Mummification
Occurs in deserts where there is no moisture of microbes, beetles, etc.
Who can legally certify a death certificate for natural death?
MEs, coroners, justice of the peace, etc.
MEs are required to sign death certificate for which manners of death? (4)
Accident
Suicide
Homicide
Undetermined
Cause of death vs. manner of death
COD is what killed the person, while manner of death is the MEs opinion (homicide, suicide, etc.)
2 major roles of the ME
Assign a COD
Render an opinion as to manner of death
ME has no duty to families, they work for society at large.
Mechanical forces causing injury (6)
Abrasions Lacerations Contusions Incise wounds Gunshot wounds Blast injury
Thermal injuries (3)
Burns
Hyperthermia (heat cramps, heat exhaustion, heat stroke)
Hypothermia
What are the 5 major categories of injury caused by physical environment?
Mechanical force Thermal injuries Ionizing radiation Electrical injuries Atmospheric pressure
What 2 systems are mostly affected by radiation?
Hematopoietic and lymphoid systems
What is the first problem that occurs when radiation is given more than 0.15 sv?
Temporary sterility
Main sites of injury and main signs and symptoms for:
0-1 sv
1-2 sv
2-10 sv
10-20 sv
> 50 sv
0-1 sv: none, none.
1-2 sv: lymphocytes, moderate granulocytopenia and lymphopenia.
2-10 sv: bone marrow, leukopenia, hemorrhage, hair loss, vomiting.
10-20 sv: small bowel, diarhea, vomiting, fever.
> 50 sv: brain, ataxia, coma, convulsions.
Accurate death certification schema:
Immediate COD (mechanism) (pneumonia)
Due to:
(Proximate) COD (COPD)
Manner of death (natural)
3 types of wounds from blunt force trauma
Abrasion
Contusion
Laceration
Wounding formula
W = E x 1/T x 1/A x K
K is modifying factors (elasticity, etc)
E is energy transferred = 1/2 MV^2
T is period of energy transfer (time)
A is area of application of force
Contusion
A bruise that results from hemorrhage into soft tissues due to rupture of subcutaneous BVs by blunt injury.
What is the epidermis like in a contusion?
It is intact and therefore a contusion does not bleed externally, but may be seen from skin or internal organs.
What do yellow, blue/purple/red and brown bruises suggest in dating a contusion?
Yellow is most significant and its presence indicated the bruise is 18 hrs or older.
None of the others are helpful.
Abrasion
3 types of abrasions
A wound where the epidermis is injured. It bleeds externally, but not profusely.
Brush (sliding/gliding)
Impact
Patterned (when abrasion reflects the surface of appearance of the instrument)
Stab wound
Sharp force creates a wound track that is greater thab the length (deeper than wide).
3 major categories of guns and their subtypes
Long guns
- bolt/lever action
- semiautomatic
- fully automatic
Smooth bores
Hand guns
- revolvers
- semiautomatics
What is the wounding formula for guns/projectiles?
KE = 1/2m x V^2
Velocity is much more important than mass
What is seen on entry wounds in:
Contact range
Intermediate range
Distant range
Contact range - marginal abrasion; soot/powder in depths of wound.
Intermediate range - marginal abrasion, powder/tattooing/stipping around wound
Distant range - marginal abrasion, no powder/tattooing/stipping, no soot/powder in depths of wound.
What is the inner and outer table separated by in the adult skull?
A diploe
How are entry and exit wounds described in the skull?
Entry wounds of outer table is sharply circumscribed, while the inner table is beveled.
If the buller has an exit wound, it is the opposite setup.
Low velocity leads to:
High velocity leads to:
Low - small entry, no exit (or small exit)
High - relatively small entry, big exit.
