WEEK 10!

Question 1

Why are PMC important?

Answer 1

They confirm death and allow the PMI to be estimated

Question 2

What are the problems with PMC?

Answer 2

They can produce confusing artefacts, destroy evidence of injury, identify and disease.

Question 3

When are PMCs useful?

Answer 3

In forensics

Question 4

When do early changes occur?

Answer 4

Within minutes, hours or days

Question 5

When do late changes occur?

Answer 5

Within weeks, months or years

Question 6

What are the three early stage changes?

Answer 6

Algor mortis
Rigor mortis
Liver Mortis

Question 7

What is algor mortis ?

Answer 7

• Used to estimate PMI within first 24 hours, only in temperate climates, can be problems with this when the person does not die at 37 degrees.

Question 8

Reasons why a person doesn’t die at 37 degrees

Answer 8

Hypothermia 
Cardiac failure 
Haemorrhage 
Heatstroke 
Fever 
exercise 
cocaine

Question 9

In what ways can heat be lost from the body?

Answer 9

Conduction
Convection
Radiation
Evaporation

Question 10

What is livor mortis?

Answer 10

Darkening of death. Seen as pink/purple discolouration of the skin. Results in the gravitational pooling of blood in the vessels forming a horizontal fluid level.
Compression on tissue prevents blood from pooling there.

Question 11

Why is livor mortis not a good PMC?

Answer 11

It can start before death i.e. in cardiac failure

Question 12

What is rigor mortis?

Answer 12

Stiffening of death.
Muscles require ATP to unbind and when you run out of ATP then there is no way to unbind the muscles.
Calcium also builds up promoting binding.

Question 13

Can rigor mortis be broken?

Answer 13

Yes and it will not return

Question 14

Will a body at a higher temp get rigor mortis faster than a body at a low temp?

Answer 14

Yes

Question 15

Timescale of rigor and algor mortis

Answer 15

Warm and no RM <3
Warm and RM 3-8
Cold and RM 8-36
Cold and no RM >36

Question 16

Timescale of livor mortis

Answer 16

<6 blanching
10-2 partially fixed
>24 fully established

Question 17

What are the two late stage changes?

Answer 17

Autolysis

Putrefaction

Question 18

What is autolysis?

Answer 18

The enzymatic breakdown of cells and tissues it happens first

Question 19

What is putrefaction?

Answer 19

Bacterial breakdown of cells and happens between 21-38 degrees. Bacteria from the GI and respiratory or infections. Green discolouration, swelling on the face and neck because of gas, redding fluid from the nose and mouth, skin slippage, blistering, hair slippage etc

Question 20

What temp is required for putrefaction?

Answer 20

21-38

Question 21

What are the 5 method of decomposition?

Answer 21

Adipocere 
Maceration 
Wet putrefaction 
Skeletonization 
Mummification

Question 22

What is adipocere?

Answer 22

Saponification of soft tissue , requires wet conditions, transformation of body fat to oleic and appears yellow, white and brown and waxy

Question 23

What is maceration ?

Answer 23

Sterile autolysis of the foetus

Question 24

What is wet putrefaction?

Answer 24

Enzymatic and bacterial

Question 25

What is skeletonization?

Answer 25

happen a long time after death

Question 26

What is mummification?

Answer 26

Desiccation of soft tissues, occurs in cool dry conditions, skin dries and shrinks and becomes leathery.

Question 27

What is a injury?

Answer 27

Damage causes by heat, cold, electricity, chemicals and radiation

Question 28

What is a lesion?

Answer 28

Any area of injury, disease or local degradation in a tissue causing a change in its structure or function

Question 29

What factors effect the injury?

Answer 29

``` Degree of force Areas of application Duration Direction Tissue properties ```

Question 30

What is the Ek?

Answer 30

Kinetic energy, E=1/2 mv^2

Question 31

What considerations should you make when determining the cause of an injury?

Answer 31

``` Superficial or deep Areas of perceived harm Accessibility of area Fatality hesitation Concealment ```

Question 32

What are the different types of mechanical force that can cause an injury?

Answer 32

``` Impact Angulation Compression Traction Torsion Shearing Acceleration ```

Question 33

What is a blunt force wound?

Answer 33

Injury caused by contact with a blunt instrument. Normally occur together.

Question 34

Types of blunt force injury?

Answer 34

Abrasion Bruise Laceration

Question 35

What is an abrasion?

Answer 35

Superficial/partial thickness skin injury. Not clinically significant but important in forensics. Often imprint abrasions.

Question 36

What are the 3 types of abrasion?

Answer 36

Imprint - Crushing vertical force Scraping - Tangential force Graze - Board surface (i.e. road rash)

Question 37

What is a bruise of an organ called?

Answer 37

Contusion

Question 38

What should you always consider about a bruise?

Answer 38

May have moved, colour doesn't tell you anything (red is new kind of)

Question 39

What are the different types of bruise ?

Answer 39

Patterned bruise - Mirror image of the weapon

Question 40

Examples of patterned bruising

Answer 40

Tram-tracks clustered discoid Black eye

Question 41

What is a laceration?

Answer 41

Cut or tear in the skin due to crushing or rotation. Ragged edges inc. tissue bridges

Question 42

What are sharp force wounds?

Answer 42

Occur by themselves and after contact with a sharp object.

Question 43

What are the two types of sharp wound?

Answer 43

Incised | Stab

Question 44

What is an incised wound?

Answer 44

``` Superficial from slicing etc. Longer than deep Knife usually Clean edges Lots of bleeding ```

Question 45

What is a stab wound?

Answer 45

Deeper than long Bleed a lot Clean edges slit or concave if against the grain of the skin

Question 46

What are chop wounds?

Answer 46

``` Hybrid of blunt and sharp Heavy bladed instrument Occur along side many other types of wound often cause bone fractures normally longer than deep ```

Question 47

What is clinical biochemistry?

Answer 47

The study of changes in chemical composition of body fluids

Question 48

What is histopathology?

Answer 48

Study of diseases