Date post: | 17-Jan-2018 |
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Blunt-Force Trauma
• Being hit or hitting into something hard• 3 categories:
- abrasions- contusions- lacerations
Abrasions
- when part of epidermis is removed• Skin layers – epidermis (outermost)
- dermis (middle – denser, blood vessels & nerves)
- hypodermis (bottom – fat & connective tissue)
• Not very deep, heal quickly• If living, trauma = reddish-brown• If postmortem = yellow, near transparent• 3 forms of abrasions – –Brush– Impact–Pattern
• Brush (aka scrape)- when force is applied parallel to skin- ex. being dragged- skin scraped off in layers- if affect dermis – more blood scab
- Skin – damaged in direction of force; may find gravel, debris, fibers, or glass
- Info re: location or cause
• Impact – - when force is applied perpendicular
to skin skin crushed- often over bony area
• Patterned – - when imprint is left on skin- caused by intensity of impact and
crushing effect of blunt object on skin- imprint may lead to type of weapon
Contusions• = bruise – broken blood vessels
below surface of skin• Can be on internal organs also• May cause swelling = hematoma• If bleeding under dura (outer surface of
brain) – brain is compressed = subdural hematoma- quick death
• Amount of force & tissue type affect severity
• Patterned contusion – object is imprinted- good evidence
• If on internal organs, use computerized tomography (CT) to see
• CTs use X-rays to produce 3D image
• Most vulnerable to bruising:- children (looser, more delicate skin)- elderly (less supportive tissue underneath)- obese (athletes have firmer muscles to support & protect blood vessels)- alcoholics (suffer from bleeding disorders)
• Many contusions may lead to death- extensive blood loss, not enough oxygen shock
Lacerations• Tear in tissue caused by a sliding or
crushing force• Extreme force from blunt objects, a fall,
or vehicle impacts• Marks w/ irregular edges• Can be internal or external
Defensive Wounds from Blunt Force• Abrasions & contusions on hands, wrists,
& arms• May have trace evidence from weapon• Offensive wounds – when perpetrator
injures himself during struggle