Force Related Trauma Flashcards
What is force?
The thing that sets an object in motion
Formula for force
F = ma
What is kinetic energy?
The energy an object has because it is in motion
Formula for kinetic energy
KE = 1/2mv^2
What happens when motion is interrupted?
Kinetic energy is transferred
Which has a bigger contribution to KE, speed or mass?
Speed
What are the types of force in the forensic context?
Blunt force
Sharp force
Ballistic and projectile force
Combinations:
Crush forces (chopping)
Concussive forces (explosive)
What is a blunt object?
Any wide, dull object or surface without sharp edges.
What is blunt force?
Force resulting in:
a blunt object or surface striking a body
a body striking a blunt object or surface
collision between moving surface/object and a moving body
body trapped between two surfaces
What is a sharp object?
An object with a sharp edge or extremity
What is a sharp force?
Any force delivered via a sharp object resulting in:
wound with cleanly divided edges
may involve more than one tissue (same contact)
Give examples of sharp objects
Knives
Axe
Scalpel
Glass
Metal shards
What is a projectile?
Any object propelled by the application of force that then moves freely under only the force of gravity
What is projectile trauma?
Any trauma resulting from the contract of a projectile with a body
What is ballistic trauma?
Any trauma resulting from the contact of a bullet or missile with a body; AKA gunshot wound
What are the three types of projectiles? Describe their velocity.
Bullets/missiles - high
Shrapnel - low through high
Arros/arrow heads - low/medium
What is concussive force?
Destructive wave of compressed air propelled outward from an explosion
What is an explosion?
Massive, fast release of energy
What types of energy are involved in concussive force?
Blunt energy (conventional weapons)
Heat energy
Radiation energy (nuclear weapons)
What type of forces combine to make concussive force?
Blunt (waves of compressed air) and sharp (shrapnel)
What type of forces combine to form chop forces?
Blunt (weight of object) and sharp (blade)
What type of injuries can result from force?
Penetrating and non-penetrating
What is a penetrating injury?
Pierce tissue and enter the body or organs
Give examples of penetrating injuries
Stab wound
Blunt force trauma causing a rib fracture that punctures the lung
What are non-penetrating injuries?
Affect body tissues without piercing them
What are the 7 categories of traumatic injuries?
Abrasions (scrapes)
Contusions (bruises)
Lacerations (tears)
Incisions (cuts and stabs)
Crush injuries (can be mixed)
Tissue destruction
Fractures
Which of the seven categories of traumatic injuries can be caused by blunt force?
Contusions
Fractures
Lacerations
Abrasions (friction)
What is the most common mild traumatic brain injury?
Concussion
What causes concussions?
Rapid decelerations
What can cause rapid deceleration resulting in a concussion?
Collision and/or coup/countercoup injury (blunt force trauma)
Sudden stop (without blunt force trauma)
Rapid rotation (fall)
Describe a coup injury
Caused when head stops suddenly
Brain rushes forward
Injured by:
hitting inside skull
rubbing against inner ridges
Describe a contre coup injury.
Brain bounces off primary surface and impacts against opposing side of skull.
Additional injury from brain rubbing against inner ridges
What type of causes basilar skull fracture?
High velocity blunt force trauma
How prevalent are basilar skull fractures?
~20% of all skull fractures
What are basilar skull fractures correlated to?
High-risk behaviour
Example: MVA, assault, ballistic trauma (rarely)
What can lead to death as a result of basilar skull fractures?
major vessel damage
What are symptoms of anterior cranial fossa fractures?
Periorbital damage
Visual disturbance
Loss of feeling to forehead
Rhinorrhea
What are symptoms of middle cranial fossa fractures?
Otorrhea
Loss of sensation to lower face
What are symptoms of posterior cranial fossa fractures?
Battle sign, loss of gag reflex
What are the 4 types of sharp force injuries
Incisions
Stab
Fractures
PuncturesD
Differentiate between incisions and stabs
I: longer than deep
S: deeper than long
What are the 4 types of projectile injuries?
Incisions
Contusions
Fractures
Punctures
What is a cavitation injury?
Object creates a concentrated spiral of pressure that pushes tissue away from the piercing.
Differentiate between primary and secondary ballistic injuries in the brain.
Primary: due to tissue destruction
Secondary: due to sequellae of the primary injury
Describe the pathophysiology of primary brain injuries
Tissue deformation, axonal shearing, contusion, necrosis, blood-brain barrier disruption
Describe the pathophysiology of secondary brain injuries
Cerebral edema
Increase in inflammatory cytokines
Mitochondrial damage
Excitotoxicity
Ischemia
