Forensic aspects of trauma Flashcards
What is the definition of an injury?
‘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’
What can excessive mechanical force lead to?
> Compression
Traction
Torsion
Tangential (shearing)
Resultant damage depends on type of mechanical insult AND nature of target tissue
Classification of injury?
> 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
What do blunt force injuries lead to?
> Contusions (bruises) =
Burst blood vessels in skin
> Abrasions (graze, scratch) = Scraping of skin surface
> Lacerations (cut, tear) = Tear/split of skin due to crushing
Patterned bruises?
> Tramline
Finger tips
Other
Factors affecting prominence of bruising?
> Skin pigmentation > Depth and location > Fat > Age - Child + Elderly > Resilient areas > Coagulative disorders
Factors affecting prominence of bruising - Depth and location?
Depth and location – occur more readily over loose skin – eyebrow, scrotum
Factors affecting prominence of bruising - Fat?
Fat - ↑ subcut fat bruise more easily
Factors affecting prominence of bruising - Age?
Age:
> Children – skin loose and delicate
> Elderly - blood vessels of skin poorly supported + more subcutaneous fat
Factors affecting prominence of bruising - Resilient areas?
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
Factors affecting prominence of bruising - Coagulation disorders?
> Thrombocytopenia > Von Willebrand’s disease > Haemophilia > Liver disease (alcoholics) > Bone marrow disease
Kinetic energy equation?
Kinetic energy = ½ mass x velocity2
Which type of injuries are bites?
Often a mix of abrasions and lacerations
What can tissue bridges help to determine?
Can help to confirm a blunt force laceration versus a sharp force injury
How are sharp force injuries defined?
> 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
How do you determine between an incised and a stab wound?
The wound depth and length along the surface
Superficial versus deep
When looking at a stab wound how is it assessed?
> How wide the incision is
The edges of the wound can help to determine the type of weapon
The depth of the wound
Defensive type injuries?
Blunt and sharp force
Passive – victim raises arms and legs for protection
Active – victim tries to grab weapon or attackers hand
Defensive type injuries - Passive?
Passive – victim raises arms and legs for protection
Sliced, shelved often with skin flaps over backs of hands and forearms
Defensive type injuries - Active?
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
Self inflicted injuries?
> Commonly sharp force
Site of election - usually wrists/forearms, chest and abdomen
Parallel, multiple and tentative incisions
What determines the consequences of an injury?
> 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
Head injuries?
> Skull fractures – linear, depressed
> Bleeding over brain – subarachnoid, subdural, extradural (amount is critical)
Diffuse Brain injury
Moat common type of self inflicted injury?
Sharp force
Most common sites of self inflicted injury ?
Sharp for usually wrists/forearms, chest and abdomen
Diffuse axonal injury?
CLINICAL TERM – immediate and prolonged coma with no apparent mass lesion or metabolic abnormality
Traumatic axonal injury?
PATHOLOGICAL TERM – damaged axons due to trauma
TAI?
focal or diffuse (graded 1-3 depending on severity)
Why are tentative incisions good news in self harming?
A sign of testing shows a suicidal pattern not a Homicidal pattern.
Head injury and blood volume - 35ml?
Symptomatic
Head injury and blood volume - 40-50ml?
Clinical deterioation, life threatening
Head injury and blood volume - 80-100ml?
Commonly fatal due to an increased in ICP and herniation
Head injury and blood volume - >150ml?
Fatal
Injuries that can occur during resuscitation?
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
