Test 3 Death, Trauma and the Skeleton Flashcards
Trauma def
- Pathological category defined as an injury caused to living tissues by an outside force
Outside forces
- Blunt objects, projectiles, cutting instruments, chopping tools
- Hard surfaces (ground, car/trains, aircraft accident)
- Chemicals
- Fire and frost
Trauma and Law (2)
- Cause and Manner of Death
- Characteristics of the attacker
Cause and Manner of Death (5)
- Trauma that occurred at time of death (perimortem)
- Outside force that caused the death
- Number of wounds
- Multiple traumas- mostly= rage/domestic death
- Placement of the traumas
Characteristics of the attacker (3)
- Height- Location and angle of the trauma
- Sex- Stats= diff way to kill->
- Men= more violent, messy, face-to-face (Blunt trauma w metal pipe or strangulation)
- Women= More indirect (ex. Poisonning) - Handedness: Location of trauma/wounds
Bone Traumas (2)
- Fracture- When the discontinuity travels completely through the bone
- Infraction- When the discontinuity is incomplete
Types of bone breakage (4)
- Complete fracture- When once continuous surfaces no longer meet
- Hinge fracture- Part of the fracture is still attached to its original bone but not the other segment
- Comminuted fracture- Breaks that result in multiple fragments of bones. Common in violent deaths/homicides (crushing w a club), suicide (high fall, moving vehicle), and accidents (car crash).
- Fracture lines: - Radiating lines
- Concentric lines
Fracture lines- Radiating lines
Disperse outward from the area of impact
- Most common fracture lines
Fracture lines- Concentric lines
Appear around the point of impact
- Common in high-velocity projectiles
Breakage caused by non-violent factors (3)
- Pathological fractures - Osteporosis
- Stress fractures - Repeated movement (common in athletes)
- Fatigue fractures - Old age, due to the loss of cartilage
Body responses to fracture (4 steps)
ANTIMORTEM bc bone heals
1. Hematoma- Pool of blood around injury that stabilizes it (bruises)
2. Osteogenesis- Production of FLEXIBLE bone fiber
3. Callus- Flexible bone fiber turn into a bump
- 2 weeks = soft
- 4 weeks = hard
4. Bone fibers becomes true bone - After 4 weeks
Characteristics of Force causing trauma (3)
- Direction:
- Tension
- Compression
- Torsion
- Bending
- Shearing
- Speed of force
- Dynamic force
- Static force
- Focus of force
- Narrow focus
- Wide focus
Direction- Tension
Pulls on bones usu. on its long axis.
If tension is strong enough, will cause the bone to break
Direction- Compression
Pushes down on bones.
Produces fractures and fracture lines
Direction- Torsion
One part of the bone remains immobile while another segment twists.
Not very common in homicide- ex. ski/bicycle accident
Direction- Bending
Impacts the side at about right angles causing a break horizontally- Like breaking a branch.
Most commonly causing fractures
-> Parry Fracture: When someone holds their forearm up to protect themself. Blow is entirely absorbed by the ulna, causing it to bend and break= Defensive wound.
Direction- Shearing
Similar to bend, but only one side of the bone bends and the other segment remains immobile
-> Colle’s fracture: When one falls and attempt to protect themselves with their forearms. Side of the body exerts a pressure to the side of the radius.
Speed of force- Dynamic force
Sudden stress delivered powerfully and at a high speed.
Most common force seen in violent death
Speed of force- Static force
Stress applied slowly then builds up to the point where the bone breaks.
Ex.: the breaking of the hyoid bone in the throat by strangulation (most common static force)
Focus of force- Narrow
Force is applied to a single point or a thin line
-> Pointed/sharp-edged instruments. Ex.: ice picks, knives, machetes, swords…
Focus of force- Wide
Force is delivered over a large area of the bone.
-> Any other instruments other than cutting/chopping ones
Type of Trauma (4)
- Blunt trauma
- Sharp trauma
- Projectile trauma
- Miscellaneous trauma
Blunt trauma
Caused by a force that has a wide area of impact on bones.
Generally caused by: bending, shearing
dynamical and wide focus
Causes: hinge or complete fracture, and often comminuted fractures with fracture lines (both)
Sharp trauma
- Compression or shearing
- Axe= comminuted fractures with radiating lines
- Focus= narrow (knives) or wide (axe)
- Speed= dynamic
Projectile trauma
- Compression and bending
- Speed= dynamic
- Focus= narrow at point of entry, but wide upon exiting
- Comminuted fractures with fracture lines (both)
Miscellaneous trauma
Trauma that do not fit into other categories
- Static pressure: strangulation
- Generalized dynamic pressure: explosions
- Traumas caused by chemicals and heat
Varies…
Timing of bone injury (3)
- Antemortem trauma
- Perimortem trauma
- Postmortem trauma
Antemortem trauma
Clearest evidence= callus bump
How to recognize a Callus: - Irregular shape
- Disorganized surface
- Raised above surrounding area
Perimortem trauma
Injuries that occurs around the time of death
3 main distinctive characteristics:
1. Breakage displays sharp and irregular edges
2. Formation of fracture lines (only on moist bones)- radiating or concentric
3. Shape of broken ends- do not fracture at right angle, nor have flat broken surfaces. -> Dry bones do= diff btw peri/post
Postmortem
Fracture to dry bones : 3 main distinctive characteristics:
1. No fracture lines
2. Bones break at right angles w almost flat surfaces
3. The color of the bone is diff. Broken surface will be normally lighter in color than other bone surfaces
