Exam 2 decomposition Flashcards
Discussing the concepts mentioned in the decomposition section of exam 2
what is the definition of death?
Total irreversible stop of the bodily functions of the major organs.
Antemortem
Before death
Perimortem
Around the time of death
Postmortem
After death
How do you estimate postmortem interval or PMI?
PMI is the time between death and the discovery of the body.
Only an estimate
can be influenced by these things: temperature, the health of the person before death, or the environment
what are some methods to determine the PMI of a body?
Witnesses - When last seen alive
Scene - mail, food decay, answering machine, phone calls
changes in the body - forensics
What is the postmortem clock?
the natural biological changes in the body that follow death.
chemical changes in the bodily fluids’ decomposition
survival injuries
psychological changes with progression rates of the decomposition
Rigor mortis
Stiffness of the body after death
- Affects the smaller muscles before the bigger ones.
- This happens after the body is out of ATP in the muscle fibers
- Full rigor sets in 4 hours after death
- Generally disappears after 24 - 48 hours
Livor mortis (lividity)
- Is the pooling of uncirculated blood, causing discoloration to the parts of the body touching a surface. it settles in the body due to gravity.
-results in a purplish discoloration on the affected areas.
-Sets in 1 hour after death and peaks in 3-4 hours
-Can indicate if the body was moved, is affected by clothing, hard/soft surfaces
- Lividity becomes set around 12 hours after death, slowly disappears with decomp after 36 hours
Algor mortis
the cooling of the body after death, assuming the temp of the room stays consistent.
the general rule of thumb for measuring the body cooling rate
The poor rule of thumb: body cools about 1.5F per hour after the first 8 hours
If the body is cold, it has been dead for a while; if it is around 98.6F it has not been dead for long
Initial Decay (autolysis Period)
- 0 - 3 days PM
- Rigor mortis sets in and fades
-Livor mortis sets in
-Body cools for first 12 hours; Algor mortis - Flies are attracted, lay eggs in natural body openings and wounds
-Cells in the body break down, bacteria in gut start to digest organs
This stage can also be known as autolysis
Putrefaction (Gaseous period)
- 4 - 10 days PM
-Rigor has faded, issues in body are now soft - bacteria in gut have broken down the abdominal tissues, releasing fluids and gas into the body cavities
- gas may cause bloating in the abdomen
internal pressures cause gas and fluids to leak out of the body, with foul smelling odors - maggots hatch, forming mass that consumes the body
- more insects attracted to the body
Black Putrefaction (Liquidification period)
10 - 20 days PM
- Bloated body collapses onto itself, strong smell of decay
- Remaining flesh turned into creamy consistency
- Exposed body parts are black in color
- Large volumes of liquid drain from the body, seeping into the soil below
Butyric Fermentation (skeletonization period)
20 - 50 days PM
- All remaining flesh has disappeared, body becomes dry
- Has a slight cheesy smell from Butyric acid
- Surface of body touching the ground starts to mold
