Forensic Aspects of Trauma

Question 1

What is an injury?

Answer 1

A disruption in the integrity of the tissues resulting from the application of an external force

Question 2

What might injuries involve?

Answer 2

Skin, internal tissues and organs

Question 3

What is injury the consequence of?

Answer 3

Transfer of energy - the greater the energy transferred, the greater the disruption of the tissue and so the greater the injury
If enough energy is transferred the injury will be fatal

Question 4

What are the types of energy?

Answer 4

Mechanical e.g. from weapon to body 
Thermal 
Electrical 
Radiation
Chemical

Question 5

What does there need to be for an injury to occur?

Answer 5

A victim
A weapon
An interaction between them

Question 6

What are the determinants of the nature of any resultant injury?

Answer 6

Force - the greater the energy the greater the force
Area - over which the force/energy is delivered
Duration
Direction

Question 7

If a patient is mobile, where will some of the energy causing an injury be dissipated?

Answer 7

In their movements and therefore less will be focused on the injury site compared to an immobile patient

Question 8

What parts of the body will people present when an injury is being inflicted on them?

Answer 8

Parts that are less vulnerable e.g. arms and legs to protects face, head, internal organs etc.

Question 9

What are the biological factors affecting an injury?

Answer 9

Mobility
Anticipation, co-ordination and reaction
Biomechanical properties of the tissues

Question 10

How do the biomechanical properties of the tissues affect an injury?

Answer 10

Penetrating weapon hitting bone instead of soft tissue - bone will likely stop a blade whereas it would continue to travel through soft tissue
Energy applied will transfer more in hard external tissues than in soft tissues

Question 11

What is a contusion?

Answer 11

Bruise

Question 12

What are the features of bruising?

Answer 12

Does not necessarily show point of contact - bruises expand outwards so won’t show direct point of contact
Deep bruising and blood tracking commonly occur
Some bruises may only bruise superficially (dermis) in which case the point of contact and patterns of bruising will be more indicative of the injury

Question 13

What is bruising due to?

Answer 13

Breaking of blood vessels

Question 14

When is blood tracking important?

Answer 14

In paediatric trauma when considering non-accidental injury e.g. two black eyes are difficult to obtain accidentally, more commonly blood tracking from an injury to the head higher up

Question 15

What are brush abrasions?

Answer 15

When wide areas of the body are dragged along a surface e.g. motorcycle accidents

Question 16

What are the features of abrasion?

Answer 16

Confined to the skin
May show an imprint of the causative weapon
Will show point of contact

Question 17

What is a laceration?

Answer 17

Force spread over an area causing tearing of the skin/tissue

Question 18

What are the features of laceration?

Answer 18

Irregular
Presentation depends on energy applied
Tissue will tear in whatever plane is maximally deformed, weakest and least resistant
More extensive debridement and exploration needed than in incisions
Poorer cosmetic outcome
Scarring and infection risk

Question 19

What are lacerations bridged by?

Answer 19

Bits of stronger tissues e.g. nerves

Question 20

What is an incision?

Answer 20

Cutting using a sharp blade

Question 21

What are the features of incisions?

Answer 21

Typically greater length than depth
Wound will have defined margins with no bridging of tissues
Tends to be no surrounding injury unless additional blunt force energy was applied
Minimal debridement and cosmetic surgery needed

Question 22

What are the features of stab wounds?

Answer 22

Generally deep wounds (depth variable)
Surface injury may not be indicative of depth and severity of injury, unless a major blood vessel has been damaged and severe bleeding is occurring

Question 23

What are the other types of injury?

Answer 23

Blunt penetrating 
Firearm injuries - huge energy and velocity, causes cavitation of the tissues through which the bullet travels and then tissue recoil 
Thermal injuries 
Electrical burns 
Fractures 
Haemorrhage
Asphyxia

Question 24

What are the types of anoxia?

Answer 24

Anoxic anoxia - smothering, neck compression
Anaemic anoxia - reduced Hb, CO poisoning
Stagnant anoxia - usually in cardiac failure
Histotoxic anoxia - cells poisoned e.g. cyanide poisoning

Question 25

Why is pain generally not felt at the time of injury?

Answer 25

Due to adrenaline

Question 26

What are some factors of acting capacity?

Answer 26

Injured person’s ability to run away/remove themselves from the harmful situation etc.

Question 27

What are the modes of death?

Answer 27

Natural 
Unnatural - homicide, suicide, accident 
Homicide - assault, culpable homicide, manslaughter 
Suicide - self-inflicted 
Accident - unpredictable

Question 28

How do we attempt to distinguish the mode of injury?

Answer 28

By considering;

• pattern of injury/injuries e.g. position, defensive injuries vs tentative (self-harm)
• circumstances e.g. evidence of eye-witnesses
• common sense