Forensic aspects of trauma Flashcards
Define the term ‘mechanism of injury’
MOI refers to the method by which trauma to skin, muscles, organs, and bones occurs
Look
An important factor of MOI is the area over which the force acts:
- If you have a plank of wood and you hit someone with the narrow edge rather than the wide edge…
- The force derived from the same mass and velocity is applied over a smaller area, thus delivering a greater impact to any given unit of tissue
What can excessive mechanical force cause?
- Compression
- Traction - adhesive friction of a body on a surface on which it moves.
- Torsion - twisting
- Tangential (shearing)
Blunt force injuries
Caused by impact with blunt object – ground, fist, foot, weapon
- Contusions (burst blood vessels in the skin)
- Abrasions (scraping of skin surface)
- Lacerations (tear/split of skin due to crushing)
When might someone get tramline bruises?
When a person is struck with a cylindrical object, such as an iron bar, or baseball bat etc, the bruise pattern formed is quite distinct.
When might someone get finger tip bruising?
Where an assailant has forcefully gripped a person, for example around the neck (e.g. during attempted manual strangulation) or arms etc, one may see small discoid or ovoid bruises in a cluster
What factors affect how prominent the injury is? (6)
- Skin pigmentation
- Depth and location – occur more readily over loose skin – eyebrow, scrotum
- Fat - ↑ subcut fat then you bruise more easily
- Age - Children – skin loose and delicate - Elderly - blood vessels of skin poorly supported
- 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
- Coagulative disorders – thrombocytopenia, Von Willebrand’s disease, haemophilia, liver disease (alcoholics), bone marrow disease
Sharp force injuries
Injury caused by any weapon with sharp cutting edge - superficial or penetrating
- Incised wounds - Superficial sharp force injury caused by slashing motion. It is 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
Definition of an injury
Physical harm or damage to someone’s body caused by an accident or an attack due to the application of mechanical force
The resultant damage from MOI depends on what?
The type of mechanical insult Nature of target tissue Forces involved – high speed RTC, fall from height, kicking, stamping, punch Number of impacts – multiple vs single
How is an injury classified
- 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 are some defensive types of injuries?
Blunt and sharp force
- Passive – victim raises arms and legs for protection
- Sliced, shelved often with skin flaps over backs of hands and forearms
- 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
How might you get a Traumatic Subarachnoid Haemorrhage?
Due to rapid rotational movement of head, usually as the result of a single punch to jaw/ upper part of neck or side of head Sudden unexpected twisting movement
What happens to the vessels in the brain in Traumatic Subarachnoid haemorrhage?
They rupture causing you to immediately become unconscious and in cardiac arrest
