Forensic aspects of trauma

Question 1

What is the definition of an injury?

Answer 1

‘physical harm or damage to someone’s body caused by an accident or an attack’

‘Damage to any part of the body due to the application of mechanical force’

Question 2

What can excessive mechanical force lead to?

Answer 2

> Compression
Traction
Torsion
Tangential (shearing)

Resultant damage depends on type of mechanical insult AND nature of target tissue

Question 3

Classification of injury?

Answer 3

> Appearance or method of causation: Abrasion, contusion, laceration, incised wounds, gunshot wounds, burns

> Manner of causation:
Suicidal, accidental, homicidal

> Nature of injury:
Blunt force, sharp force, explosive

Question 4

What do blunt force injuries lead to?

Answer 4

> Contusions (bruises) =
Burst blood vessels in skin

> Abrasions (graze, scratch) = Scraping of skin surface

> Lacerations (cut, tear) = Tear/split of skin due to crushing

Question 5

Patterned bruises?

Answer 5

> Tramline
Finger tips
Other

Question 6

Factors affecting prominence of bruising?

Answer 6

> Skin pigmentation
> Depth and location 
> Fat 
> Age - Child + Elderly 
> Resilient areas
> Coagulative disorders

Question 7

Factors affecting prominence of bruising - Depth and location?

Answer 7

Depth and location – occur more readily over loose skin – eyebrow, scrotum

Question 8

Factors affecting prominence of bruising - Fat?

Answer 8

Fat - ↑ subcut fat bruise more easily

Question 9

Factors affecting prominence of bruising - Age?

Answer 9

Age:
> Children – skin loose and delicate
> Elderly - blood vessels of skin poorly supported + more subcutaneous fat

Question 10

Factors affecting prominence of bruising - Resilient areas?

Answer 10

Buttocks, abdomen – bruise less easily with given impact than areas with underlying bone which acts as an anvil with skin between bone and inflicting object

Question 11

Factors affecting prominence of bruising - Coagulation disorders?

Answer 11

> Thrombocytopenia
> Von Willebrand’s disease
> Haemophilia
> Liver disease (alcoholics)
> Bone marrow disease

Question 12

Kinetic energy equation?

Answer 12

Kinetic energy = ½ mass x velocity2

Question 13

Which type of injuries are bites?

Answer 13

Often a mix of abrasions and lacerations

Question 14

What can tissue bridges help to determine?

Answer 14

Can help to confirm a blunt force laceration versus a sharp force injury

Question 15

How are sharp force injuries defined?

Answer 15

> Superficial or penetrating

> Incised wounds:

• Superficial sharp force injury caused by slashing motion
• Longer on the skin surface than it is deep

> Stab wounds:

• Penetrating injury resulting from thrusting motion
• Wound depth greater than length on the surface

Question 16

How do you determine between an incised and a stab wound?

Answer 16

The wound depth and length along the surface

Superficial versus deep

Question 17

When looking at a stab wound how is it assessed?

Answer 17

> How wide the incision is
The edges of the wound can help to determine the type of weapon
The depth of the wound

Question 18

Defensive type injuries?

Answer 18

Blunt and sharp force

Passive – victim raises arms and legs for protection

Active – victim tries to grab weapon or attackers hand

Question 19

Defensive type injuries - Passive?

Answer 19

Passive – victim raises arms and legs for protection

Sliced, shelved often with skin flaps over backs of hands and forearms

Question 20

Defensive type injuries - Active?

Answer 20

Active – victim tries to grab weapon or attackers hand

Sliced shelved incised wounds on palmer aspect of hands and web spaces between fingers – particularly between thumb and index finger

Question 21

Self inflicted injuries?

Answer 21

> Commonly sharp force
Site of election - usually wrists/forearms, chest and abdomen
Parallel, multiple and tentative incisions

Question 22

What determines the consequences of an injury?

Answer 22

> Type of mechanical insult – blunt, sharp, homicide, suicide, accident etc

> Nature of target tissue - head, chest, abdomen, fat

> Forces involved – high speed RTC, fall from height, kicking, stamping, punch

> Number of impacts – multiple vs single

Question 23

Head injuries?

Answer 23

> Skull fractures – linear, depressed

> Bleeding over brain – subarachnoid, subdural, extradural (amount is critical)
Diffuse Brain injury

Question 24

Moat common type of self inflicted injury?

Answer 24

Sharp force

Question 25

Most common sites of self inflicted injury ?

Answer 25

Sharp for usually wrists/forearms, chest and abdomen

Question 26

Diffuse axonal injury?

Answer 26

CLINICAL TERM – immediate and prolonged coma with no apparent mass lesion or metabolic abnormality

Question 27

Traumatic axonal injury?

Answer 27

PATHOLOGICAL TERM – damaged axons due to trauma

Question 28

TAI?

Answer 28

focal or diffuse (graded 1-3 depending on severity)

Question 29

Why are tentative incisions good news in self harming?

Answer 29

A sign of testing shows a suicidal pattern not a Homicidal pattern.

Question 30

Head injury and blood volume - 35ml?

Answer 30

Symptomatic

Question 31

Head injury and blood volume - 40-50ml?

Answer 31

Clinical deterioation, life threatening

Question 32

Head injury and blood volume - 80-100ml?

Answer 32

Commonly fatal due to an increased in ICP and herniation

Question 33

Head injury and blood volume - >150ml?

Answer 33

Fatal

Question 34

Injuries that can occur during resuscitation?

Answer 34

Resuscitation – Bruising neck and chest, finger marks, bruising /laceration pf lips and gums, damage to teeth, sternal and rib fractures, pleural cavity heamorrhage, laceration of lung, heart rupture, venepuncture and cannulation