legal medicine

Legal Medicine: OTHER FORMS OF PHYSICAL

INJURIES/DEATH

(Explosion, Automotive and Sports Injuries)

Lysa Lynn Uy-Libanan, MD DPSP

8/3/2012 Legal Medicine CPU

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EXPLOSIONS/ BLAST INJURIES:

Definition:

EXPLOSION – sudden release of potential energy

- localized increase in pressure

When investigating:

1. What?

2. Cause?

3. How?

4. Mechanism?

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• Classification: – Hydraulic / Mechanical – pressure inside a sealed

container exceeds its structural strength

– Electrical – meeting of two or several electrical arcs/different electrical potentials producing high degree of heat that causes expansion of the surrounding air ( e.g. lightning)

– Nuclear – fusion or fission of atomic nuclei

– Chemical – chemical reaction may produce heat that dissipates into the surrounding



• Types of Chemical Explosion: a. Diffused Reactant – must be initiated by

spark/flame/heat

volatile gas + air = heat + pressure

e.g – internal combustion of heat

b. Condensed Reactant

- chemical reaction from a solid /liquid substance that produce large quantities of gas and heat

- with point of origin – most severe damage when closest to the source

- oxygen is not a requirement to trigger the explosion



Classification of Condensed Reactant Explosives:

1. Low Order (Deflagrating Explosive)

- rely on burning and confinement slow build up of heat and pressure (e.g. Gunpowder explosion)

2. High Order

- detonation – requires a chemical process that rapidly decomposed nitrogenous compounds producing heat and gas as by-products

- shock-wave effect explosion

- e.g. Dynamite; Symtex explosives

- Maybe: Stable vs Unstable



Death due to explosives

- destructive effects varies with the kind/amount of explosives, location of the victim and time of explosion:

1. victim in contact with the explosive

- complete disruption or fragmentation, distortion and bursting effect of body caused by compression- decompression effect of the explosion

2. victim within the perimeter of explosive

- severity will depend on the nearness to the source of explosion

- punctate bruises, abrasions and lacerations to dismember or disembowel body parts



Death due to explosives

3. Far from explosion – “peppering” injuries

4. Other effects:

- blast wave effect – can knock down a person unconscious; disrupts or lacerates internal organs and senses

- Burn injury from flames and heated gas

- Asphyxia due to lack of oxygen

- Inhalation of poisonous gasses

- Direct injuries by flying / falling debris

- “Shrapnel wound”



Identification at the site of explosion and collecting of evidences:

1. Presence of crater

2. Search area for traces of detonation mechanism

3. Sampling of debris



Atomic Bomb Explosion:

- fission of atomic nuclei (e.g. 100 lbs uranium) liberates energy equivalent to several tons of TNT

- “Mushroom” clouds – ball of luminous gasses and clouds containing fission products

- “ million pounds/sq inch of heated gas, heat comparable to the sun, light 30x brighter than noontime sun”

- shock wave move sidewards in all direction



• Rays emitted during nuclear explosions: – Alpha – positive charge helium; high linear energy transfer with poor

penetrating power; can be stopped by sheet of paper

– Beta – either positive of negative charged electrons; higher penetrating power than alpha rays but less ionizing power

– Gamma – short rays with high energy and greater penetrating power; cause much tissue damage

– Neutron – Uncharged; highly penetrating power

• Effects of atomic explosion – tissue damage is inversely proportional to the distance from the explosion



Factors responsible for the effects of radiation:

1. Age

2. Dosage

3. Kind of Radiation

4. Fractional Dose

5. Sensitivity



Other Sources of radiation:

1. Natural Source

a. Cosmic

b. Terrestrial – radiothorium series of granite rocks

2. Man-made

a. Diagnostic Xrays

b. Clinical nuclear pharmaceutical agents

c. Therapeutic radiation apparatus

d. Nuclear power plants


AUTOMOTIVE CRASH/ACCIDENTS: FACTORS RESPONSIBLE TO AN AUTOMOTIVE CRASH:

1. Human (Driver) 1. Mental attitude

2. Perceptive defect

3. Delayed or Sluggish reaction time

4. Disease

5. Chemical

2. Environmental

3. Mechanical (Machine/vehicle)

4. Social

5. Pedestrian


AUTOMOTIVE CRASH/ACCIDENTS: Injuries and Death on the Driver and the Passenger: - two collisions: 1. First Collision - impact of moving vehicle with another vehicle or a fixed

object; moving vehicle decelerates and stops after impact

- degree of damage depends on the speed of the moving vehicle and the vehicles involved.

2. Second Collision - unrestrained occupants of the moving vehicle - moves in the same direction and the same velocity towards the

point of impact - Displacement, ejection or distribution resulting in direct impact

injuries


AUTOMOTIVE CRASH/ACCIDENTS:

FRONT IMPACT CRASH:

1. Driver – may strike the steering wheel, hub of steering column, wind shield, rear view mirror side window, dash board; usually head, face, neck and chest injury

2. Front Seat passenger – same with the driver

3. Rear seat occupants

- may strike the back of the front seat, pillar between two front seats, rear side doors, maybe propelled over the front seat striking the driver or the front seat passenger, the dashboard and/or the windshield


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SIDE IMPACT CRASH

- Common at street intersections

- causes severe injuries because the vehicle has less structural components to absorb the force of impact and the sides are less rigid to prevent the intrusion into the passenger compartment

- usually lateral impacts cause injuries to the chest (rib fractures, contusion and laceration of the lungs, visceral organ damage like liver, spleen and kidneys)


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AUTOMOTIVE CRASH/ACCIDENTS: REAR IMPACT CRASH - May occur after change of lane in an express way or crash at the

rear of a parked vehicle

- With rear impact – head moves backward / hyperentend followed by forward movement until the chin strikes the front portion of the chest/ hyperflexion

- “Whiplash” injury --- “acceleration-deceleration” – may result to muscle spasm or injury to the ligaments of the neck

- May cause damage to gas tank at the rear of the vehicle – causing explosion

ROLL OVER CRASH (Turn-Turtle Impact) - Unrestrained occupant may be pinned, crushed or ejected


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SUICIDAL CRASH

- Usually “single” affair – single vehicle, single occupant

- Head on collision with roadside object

- No evidence of any effort to apply the brake or to avoid striking the object (foot of the driver still on the accelerator pedal)

- History of previous suicide attempts


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HOMICIDE BY MOTOR VEHICLE

- death usually on account of negligence and rarely intentional

- Reckless driving, lack of necessary skills, aggressive behavior, under the influence of drugs

- “HIT AND RUN”

- Sometimes a simulation of a crash may occur to conceal a crime


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PEDESTRIAN-VEHICLE COLLISION

1. Primary impact – first violent contact bet the pedestrian and the vehicle; usually bumper hits the leg of the victim; severity of the injury depends on the position of the victim when the impact occurred, the speed of the vehicle and the amount of bodily support

2. Secondary Impact – impact of the pedestrian to the ground or other object after the first impact; injury sustained depends on the force of ground impact, the nature of the road and parts of the body involved.


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PEDESTRIAN-VEHICLE COLLISION

3. Run Over Injuries

- may occur during first impact or thereafter

- crash fractures, skid or tire marks, rupture of internal organs and internal hemorrhage

- instantaneous death

4. Hit and Run injuries

- fast moving, hit or side swipe, or collide


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MOTORCYCLE CRASH

High percentage of accidents because:

1. motorcycle can attain high speed

2. small profile

3. sometime difficult to control when at high speed and in curved road


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MOTORCYCLE CRASH

Severe injuries because:

1. less crushable materials to absorb the impact

2. no restraint system


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ATHLETIC SPORTS BOXING - Potential injuries: - most common site - facial injuries - “spectacle hematoma” – serous effusion on the loose

tissue around the eyeball and in the eyelids; puffiness and closure of eyes

- “cauliflower ear” - scarring and fibrosis brought abour by hemorrhagic trauma and necrosis of the auricular cartilage of the ear pinna

- retinal detachment - fracture of nasal septum, mandible and maxilla - Renal damage - Intracranial injuries – most serious sequalae


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ATHLETIC SPORTS BOXING Intracranial injuries – Cerebral concussion - transient LOC - Subdural Hemorrhage most common injury which may

be localized or extensive; due to tear in dural emissary vein

- Pontine hemorrhage – aka “Boxer’s hemorrhage” - due to severe head blow causing acute flexion

and extension of the head resulting in brainstem to be pinched over the tentorium with hemorrhage


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ATHLETIC SPORTS BOXING Effects on the brain of a boxing blow depends on the location,

direction, intensity, velocity and number of blows: 1. Rotation (Angular) Acceleration - direct blow causing rotation of the head sideways will

cause the inert brain to lag behind the accelerated skull - effects: 1. Subdural hematoma 2. Intracerebral hemorrhage 3. Diffuse Axonal Injury 2. Linear (Translational) Acceleration - straight on the face causing focal ischemic lesions in the

cerebellum


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ATHLETIC SPORTS BOXING 3. Injury to the carotid vessels - blows in the neck area - dissecting aneurysm or thrombus occlusion - carotid reflex hypotension and bradycardia 4. Impact deceleration - fall on the back causes deceleration injury - contre coup contusions of the orbital surface of the

frontal lobes and the tips of temporal lobes “Punch Drunkenness” – traumatic or pugillistic encephalopathy - slurred speech, slow clumsiness, unsteady gait, tremor,

progressive dementia


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END!!!


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