Forensic Aspects of Trauma Flashcards
What is an injury?
A disruption in the integrity of the tissues resulting from the application of an external force
What might injuries involve?
Skin, internal tissues and organs
What is injury the consequence of?
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
What are the types of energy?
Mechanical e.g. from weapon to body Thermal Electrical Radiation Chemical
What does there need to be for an injury to occur?
A victim
A weapon
An interaction between them
What are the determinants of the nature of any resultant injury?
Force - the greater the energy the greater the force
Area - over which the force/energy is delivered
Duration
Direction
If a patient is mobile, where will some of the energy causing an injury be dissipated?
In their movements and therefore less will be focused on the injury site compared to an immobile patient
What parts of the body will people present when an injury is being inflicted on them?
Parts that are less vulnerable e.g. arms and legs to protects face, head, internal organs etc.
What are the biological factors affecting an injury?
Mobility
Anticipation, co-ordination and reaction
Biomechanical properties of the tissues
How do the biomechanical properties of the tissues affect an injury?
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
What is a contusion?
Bruise
What are the features of bruising?
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
What is bruising due to?
Breaking of blood vessels
When is blood tracking important?
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
What are brush abrasions?
When wide areas of the body are dragged along a surface e.g. motorcycle accidents
What are the features of abrasion?
Confined to the skin
May show an imprint of the causative weapon
Will show point of contact
What is a laceration?
Force spread over an area causing tearing of the skin/tissue
What are the features of laceration?
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
What are lacerations bridged by?
Bits of stronger tissues e.g. nerves
What is an incision?
Cutting using a sharp blade
What are the features of incisions?
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
What are the features of stab wounds?
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
What are the other types of injury?
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
What are the types of anoxia?
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
Why is pain generally not felt at the time of injury?
Due to adrenaline
What are some factors of acting capacity?
Injured person’s ability to run away/remove themselves from the harmful situation etc.
What are the modes of death?
Natural Unnatural - homicide, suicide, accident Homicide - assault, culpable homicide, manslaughter Suicide - self-inflicted Accident - unpredictable
How do we attempt to distinguish the mode of injury?
By considering;
- pattern of injury/injuries e.g. position, defensive injuries vs tentative (self-harm)
- circumstances e.g. evidence of eye-witnesses
- common sense
