decomposition

Question 1

what is decomposition?

Answer 1

decaying cause by bacteria or fungal action, reducing the body of a living organism to simpler forms of matter.

Question 2

what is the translation of Taphonomy?

Answer 2

Taphos= burial, Nomos= law

Question 3

what does taphonomy mean?

Answer 3

the study of the processes that affect decomposition, dispersion, erosion, burial and re-exposure of organisms.

Question 4

what are the effects on vegetation?

Answer 4

differential plant growth can be visible for years- from the air can be used to search for clandestine graves

Question 5

what is a species marker for mass graves?

Answer 5

wormwood in the Balkans

Question 6

what is forensic taphonomy?

Answer 6

study of the fate of human remains, can help understand and reconstruct the events surrounding a death

Question 7

what are the 5 stages of decomposition in order?

Answer 7

fresh
bloat
active decay
advanced decay
skeletonization

Question 8

what regulates decomposition

Answer 8

decomposer community
physiochemical environment

Question 9

what is the definition of catalysis as a mechanism of decomposition:

Answer 9

enzymatic and chemical reactions transforming complex compound into simple molecules

Question 10

what are other mechanisms of decomposition?

Answer 10

physical and mechanical breakdown of matter, bacteria

Question 11

why is post mortem interval important?

Answer 11

COD, helps to eliminate suspects and reconstruct sequence of events

Question 12

what is the rate method

Answer 12

measuring the change produced by a process which takes place at a known rate which was initiated or stopped by the death

Question 13

what is the occurrence method

Answer 13

comparing the occurrence of events which took place at known times with the occurrence of the death

Question 14

what is Early PMI estimation based on

Answer 14

anatomical and physical changes

Question 15

what are some of the anatomical and physical changes of early PMI estimation

Answer 15

eye, muscle and tissue changes

Question 16

what are some fresh stage typical traits

Answer 16

skin pales- pallor mortis
blood gradually becomes acidic
changes to body temp after 15 mins

Question 17

what is autolysis

Answer 17

it is self digestion or cell death and is the primary driver of decomposition

Question 18

what is algor mortis

Answer 18

newton’s law of cooling- the cooling of the body after death. approx 0.78 degrees C

Question 19

how is temp measured during algor mortis

Answer 19

best way is rectally or through the liver- more accurate in first 24 hrs

Question 20

what is Hensge nomogram

Answer 20

diagram representing the relationship between 3 or more variables- in this case temp. he created 2 one for ambient temp up to 23 degrees and one for temps above

Question 21

what are some rules of Hensge diagram

Answer 21

• no strong radiation
• no strong fever or general hypothermia
• place of death has to be the same as the crime scene

Question 22

what are some influencing factors of algor mortis?

Answer 22

clothing (acts as insulation)
body size (SA:V ratio)
disease/ drugs (infections)
immersion in water (accelerates progression)

Question 23

what are some challenges of algor mortis?

Answer 23

rectal/liver temp is invasive
many exceptions of nomogram usage
when ambient temp is above 37 degrees C

Question 24

what is the first identifiable taphonomic change?

Answer 24

Livor mortis- hypostasis/ lividity

Question 25

what is lividity?

Answer 25

deep pinkish red discolouration of the skin (occur internally) appears within 30mins- 1 hr after death

Question 26

what happens with lividity

Answer 26

gravity causes the blood to settle in the dependent part of the body- like he back in the supine position

Question 27

what is blanching

Answer 27

blood can be dispersed through pressure causing white patches- provide a visual indicator of the lividity's progression.

Question 28

when does blanching peak?

Answer 28

around 3-6 hours, the blood vessels break down and the blood disperses into the surrounding tissue causing fixed staining around 8-12 hrs(confluence)

Question 29

what are influencing factors of lividity?

Answer 29

ambient temps (heat expediates, cold slaws) COD (extreme trauma) clothing (unusual patterns) diseas/ drugs (anticoagulants)

Question 30

what are challenges of lividity?

Answer 30

darker skin tones body deposition in water- reduced gravity misinterpretations (lividity vs bruising ) subjectivity

Question 31

when is lividity no longer useful?

Answer 31

once putrefaction has begun and the blood cells and vessels have started to break down

Question 32

what is rigor mortis?

Answer 32

stiffening of the muscles after death- after initial flaccidity depletion of ATP and a build up of lactic acid and calcium in the muscles fibre.

Question 33

what is the Nysten's rule (1881)

Answer 33

in the supine position: - rigor mortis begins in the mandible moving down the neck, to the trunk before finally extending to the lower and upper extremities

Question 34

when does rigor mortis begin

Answer 34

begins within 2-6 hours of death, peaking at around 12 hours and becoming completely resolved within 36 hours

Question 35

what is a cadaveric spasm

Answer 35

muscle stiffening sets in immediately- not the same as rigor mortis- muscle tense- arms can be raised, fists can be clenched.

Question 36

when does a cadaveric spasm occur?

Answer 36

drowning, car crash, homicide- because there is high tension/ excitement

Question 37

what are ocular changes?

Answer 37

clouding of cornea: 2-3 hours after death. Tache noir - black/ red discolouration - drying out of the corneal surface where the eye was slightly open

Question 38

what is the ocular changes influenced by?

Answer 38

influenced by the environment= dry, arid conditions accelerates development

Question 39

why are gastric contents important

Answer 39

can provide info on the composition of the last meal: - colour, volume, residual food

Question 40

what else can gastric contents tell us?

Answer 40

a mixed meal emptying time will depend on the volume and composition of the last meal. where the food is situated within the digestive system may also be informative

Question 41

what are some influencing factors of gastric contents

Answer 41

habits/ specific diets medication surgery (gastric sleeves) human variation (metabolism)

Question 42

what are some challenges of gastric contents?

Answer 42

subjective highly variable wide error margins can take time to collect