Difference between revisions of "Forensic pathology"

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Forensic pathology (view source)

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==Gunshot wounds==
==Gunshot wounds==
Number of entrance wound should equal the number of exit wounds -- if it doesn't there are:
{{main|Gunshot wounds}}
*Bullets in the body,
Are a relatively uncommon finding in Canada. They are dealt within a separate article.
*"Tandem bullets" -- two bullets entered at the same place,
*Secondary projectile -- the bullet hit something, e.g. bone, and made it fly out of the body,
*You missed an entrance or exit,
**Places to look:
***Below chin (common in suicides),
***In mouth (common in suicides),
***Back,
*** ... anywhere the sun don't shine.
 
===Firearm projectiles===
Two broad groups:
*Shotgun projectiles.
**Many small pellets.
*Handgun/rifle projectiles.
**Similar in size to the barrel - large when compared to shotgun projectiles.
**Bullets from handguns/rifles are marked by the barrel on the way-out (by grooves which in part spin on it to improve accuracy).
 
*Bullets are often good evidence:
**The calibre (size) and markings from the barrel (on handgun/rifle projectiles) allow it to be match to the weapon that fired it.
**Thus, all projectiles are recovered from a body... and it is routinue to X-ray all gunshot victims.
 
===Entrance wounds===
Characteristics:<ref name=denton>{{cite journal |author=Denton JS, Segovia A, Filkins JA |title=Practical pathology of gunshot wounds |journal=Arch. Pathol. Lab. Med. |volume=130 |issue=9 |pages=1283?9 |year=2006 |month=September |pmid=16948512 |doi= |url=http://journals.allenpress.com/jrnlserv/?request=get-abstract&issn=0003-9985&volume=130&page=1283}}</ref>
*Circular/round defect --especially if the projectile strikes at a right angle to the surface.
**If the projectile strikes at an angle the injury will be elliptical and the long axis of the ellipse will lie approximately in the plane the bullet traveled.
*An abrasion, or scraping, --concentric or eccentric-- usually surrounds a deep wound (key feature -- used to differentiate from exit wounds).
**Eccentric abrasion suggest directionality.
*Usually smaller than exit wounds.
**In skull the inner table defect is typically larger than outer table defect ("internal bevel").
 
Atypical entrance wounds:
*Irregular (non-circular/non-elliptical) margin.
**May be due to close range/contact.
***Classically results in a "stellate" pattern.
**Bullet ricochets --hits other object before hitting target, gun defective -- bullet's long axis doesn't coincide with its velocity vector.
***Classically results in a "D-shaped" wound.<ref name=denton/>
 
===Exit wounds===
Characteristics:
*Wsually bigger than entrance wounds.
*Morphologic shape -- variable.
**Round, stellate, ovoid.
*NO abrasion at wound margin (key feature).
*In skull -- outer table defect typically larger than inner table defect (external beveling).
 
Atypical exit wounds:
*"Shored" exit wounds.
**Exit defect created whilst surface supported/adjacent to firm surface.
**Supporting surface may lead to abrasion.
**May appear to be an entrance wound.
 
===Special entrance/exit wounds===
*Keyed wounds.
**Combination entrance/exit wounds -- result from a bullet grazing the victim.
 
===Distance of shooter===
Contact:
*Muzzle impression.
*Stellate splitting/tearing of the skin -- especially if it overlies a bony surface.
*Soot/gun powder residue - deep in the wound.
 
Close range:
*Stippling - punctate abrasions around the entrance wound.
**Suggests a distance < 60 cm.
*Soot/gun powder residue - dirt at the entrance, can be wiped-off.
 
Distant:
*No soot.
*No stippling.
 
Note:
*Absence of soot & stippling does '''not exclude''' near range -- may be assoc. with clothing or intermediate target separated from the victim post-injury.
 
===Injury severity due to GSWs===
The damage of a projectile depends on:
*Where the bullet strike, e.g. ascending aorta vs. brain vs. tibia vs. gluteus maximus.
*Kinetic energy of the bullet.
**Ek=1/2*m*v^2.
***Velocity is more important -- as it is squared (duh).
*Cavitation effect.<ref>NEED GOOD REF.</ref>


==Asphyxia==
==Asphyxia==
Michael
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