Blunt Trauma Types
• Contusions
– Black and Blue marks
• Abrasions
– Scrapes
• Lacerations
– Split versus cut
CUTTING AND STABBING
• CUTTING (INCISED) WOUNDS– sharp instrument
– longer on the skin surface than it is deep
• Edges of the wound are sharp – not usually ragged or abraded
• Surrounding skin is usually undamaged.
• No tissue bridges
• Slicing
Stabbing Wounds
• Deeper than wide
• The size of skin defect ≠ depth
• Ends of the stab wound = angles.
– May be blunt or sharp,
• Single-edged blade = 1 blunt angle and 1 sharp angle
• Double-edge knives = 2 sharp angles
• Homemade sharpened weapons = sharp or dull angles.
ID of the Weapon• Rarely is the weapon discovered in the
wound• Matching the weapon to a wound
• Tip of the blade breaks off • Can be matched to the weapon
Multiple Incised and Stab Wounds• Defense wounds
– Multiple incised and/or stab wounds of the neck, face, and extremities
– Usually caused by an assailant
• Suicide– Multiple incised wounds of neck, wrists, or leg area
– Varying depths on the wound suggest a suicide.
– Hesitation marks are characteristic
• Overkill– A body sustaining tens or hundreds of stab and incised wounds
– Highly emotional setting • Sex
• Drugs
Some Wounds Can be Caused by Treatment
• Lower two wounds were caused by thoracotomy incisions to drain blood from the chest
Internal Damage
• Heart – single-edged blade
• Multiple stab wounds in left lung and ribs
• 10 stab wounds in large incision
Head Trauma
• Contusions, lacerations, and abrasions– Obvious external signs are not necessary
• Occasionally, the weapon leaves a characteristic identifying pattern on the scalp– Exception rather than the rule.
• Blow to the head → bleeding under the scalp – May be skull fractures
– ID weapon or type of instrument
Battle’s sign
• Bluish discoloration of the skin behind the ear
• Blood leaking under the scalp after a skull fracture
Spectacle hemorrhage
• Discoloration of the tissues around one or both eyes
• Caused by a fracture of the skull
• Can be mistaken for blows to the face and eyes
There May be More than One Fracture
• Many fractures indicate more than one blow
• Need definable points of impact to determine the number of blows
Cerebral Contusion
• Focal brain injury is an injury to:
– Region, system, or side of the brain
• Most common type of focal brain injury is a cerebral contusion
• Bruise in the brain that consists of a superficial focus of brain hemorrhage, necrosis, and/or laceration.
Coup contusion
• Part of the brain receiving the focus of an impact
• Contusions and lacerations caused by heavy weapon
Contrecoup Contusion• Areas of the brain remote from the focus of
impact
• Brain bounces off opposite side of skull
Cause of Death: Subdural Hemorrhage
• Subdural hemorrhage is blood under the Dura
– tough membrane that covers the entire brain and spinal cord
• It originates from ruptured veins
• May not be an associated fracture of the skull.
Firearms – Hand Guns and Rifles• Primer – stable, but shock sensitive
• Gunpowder or propellant – volumes of gas
• Bullet or projectile
Gunpowder
1. Soot or fouling
• Completely burned gunpowder
• can be washed off the skin
2. tattooing” or “stippling.”
• Particles of burning and unburned powder
• Become embedded or abrade in the skin
What was the Range – Tight Contact
• All gunpowder residue on the edges or in the wound
• Searing or burning of wound margins
• Reddening of surrounding skin due to carbon monoxide (CO) gas produced by burning powder
• Tearing of the skin around the entrance wound (especially in head wounds) – because of pressure buildup and blow-back of the skin toward the muzzle.
Splitting Due to GasesReddening Due to CO
Muzzle Blow-back
Close range• muzzle-to-target distances of approximately 6–12”
• Both fouling and stippling are present
Abundant Soot After washing - Stipling Powder and Fouling
• Intermediate range
– muzzle-to-target distances of approximately 12” to 3’
– No fouling, only stippling or deposition of particles on clothing
• Distant wounds — No fouling or stippling.
Significance of Amount of Gunpowder Present• Different among weapons
• Different in same weapon with different ammunition
• To make a comparison– Test-fire gun in question
– Same ammunition
• The scene must be examined for bullets and cartridges.– Bullets may be under the body or caught in clothing after
exiting the body.
Entrance and Exit Wounds• Entrance wounds
– Circular defects with a thin rim of abrasion
– Entrance wounds of the face atypical• Surfaces are not flat.
• Exit wounds– More often irregular in shape
• Slit-like• Ragged edges• No Rim of abrasion unless victim is against another object
– shored
– Skin around discolored because of underlying bleeding in the soft tissues.
– May be circular like entrance wounds
Entrance and Exit
Two Exit Wounds with Hemorrhage
On the left – Entrance WoundOn the right – Exit Wound
Note beveling
Entrance and Exit Wounds
Shot in chin as going up stairs
Shotgun Injuries
• Different components
– Gunpowder
– Pellets – sometimes slug
– Wad
• The range (distance) of fire more easily determined
– Presence or absence of pellet spread
• Same gun and ammunition
ASPHYXIA• Asphyxia means death due to lack of oxygen
to the brain
– Compression of the neck
• hanging and strangulation
– Blockage of the airway
• suffocation, gagging
• Compression of the chest, neck, or face
– Postural or positional asphyxia
• Chemical or lack of available oxygen
Compression of the neck• Occlusion of the vasculature in hanging (usually
suicide), the neck can be compressed
– Not necessarily the airway (larynx or trachea)
– Very little pressure is needed
• Hanging
• Throttleing
– Unconscious in seconds
– Pressure must be continued in order to cause death.
Signs of Trauma to the Neck• Contusions or abrasions, rarely lacerations
– Abraded, imprinted mark
• Thin ligature – pattern can be matched to the particular ligature
• Wide ligature – no specific pattern
– Superficial fingernail cuts from either the victim or assailant
• Pinpoint hemorrhages, or petechiae (pet-TEA-key-eye)
– Eyes, lids, face
– buildup of vascular pressure which causes capillaries to rupture
– Not often found in suicidal hanging
– May occur in sudden natural death
• Tardieu spots
– Ruptured blood vessels in the tissues after prolonged hanging, especially in the lower extremities,
Petechiae (pet-TEA-key-eye)
•Pinpoint hemorrhages
•Eyes, lids, face
•buildup of vascular pressure which causes capillaries to rupture
•Not often found in suicidal hanging
•May occur in sudden natural death
Blockage of the airway
• Suffocation, aspiration, gagging
– Airway is blocked
• A pillow or hand placed over the mouth
• Un-chewed food or small parts of toys lodged in an infant’s or child’s airway
• Individuals without teeth or with a history of stroke or other debilitating disease may have trouble chewing and aspirate food into the airway.
• Those under the influence of alcohol are also more likely to aspirate
• Usually no signs of trauma
Postural or Positional Asphyxia• Compression of the chest, neck, or face
• person cannot breathe because of an inability to move one’s chest
• Airway is compressed against the neck or face
• Commonly seen during motor vehicle accidents– when the vehicle overturns on a victim
– driver trapped between the steering wheel and seat
• Signs of Trauma
• Few injuries– Blunt trauma
– Petechiae of the eyes and face
Alcoholic Fell Asleep with Head on Pillow
• His nose and mouth were occluded by the pillow
• autopsy showed only signs of alcoholism
• Scene investigation was essential
• Manner of death - accident
Chemical and lack of available oxygenin the atmosphere
• O2 is replaced by another chemical or gas
– Closed environment
– mine shafts, sewers, or chemical storage tanks
• Red blood cells are unable to deliver oxygen to bodily tissues
– Carbon monoxide
• Competes with O2
– Cyanide
• smells like bitter almonds
– can occur quickly, especially cyanide poisoning
Drowning• The diagnosis of drowning - exclusion
– Diatoms
– The autopsy is usually negative
• Diagnosis– Body is wet, or is found in water.
– There may be injuries from being in the water• Tears and scrapes skin from impacts against boats or bridges
• Feeding by marine life - skin of the face, especially around the mouth, nose, and ears
• Abrasions may be found on the forehead, knees, and backs of hands from scraping
– No external signs of trauma• Froth in the nose and mouth
• Wrinkling of the skin on the hands and feet
• Injuries to the body may occur from CPR attempts or from removing the body from the water.
– Heavy, wet lungs in those individuals who drown in salt water,