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Gunshot wounds (view source)

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[[Image:Gunshot_wonud_to_leg.JPG|thumb|right|Gunshot wound to the leg showing entrance and exit. (WC)]]
[[Image:Hofmann Lehrbuch brain gunshot.jpg|thumb|right|Depiction of a gunshot wound of the brain. (WC/National Library of Medicine)]]
This article deals with '''gunshot wounds''', which are seen by (forensic) pathologists in the context of forensic autopsies.
This article deals with '''gunshot wounds''', which are seen by (forensic) pathologists in the context of forensic autopsies.


An introduction to forensic pathology is in the ''[[forensic pathology]]'' article.
An introduction to forensic pathology is in the ''[[forensic pathology]]'' article.


==Accounting==
==Bullet accounting==
Number of entrance wound should equal the number of exit wounds -- if it doesn't there are:
Number of entrance wounds should equal the number of exit wounds.
*Bullets in the body,
 
*"Tandem bullets" -- two bullets entered at the same place,
If the above is not so... the explanation is:
*Secondary projectile -- the bullet hit something, e.g. bone, and made it fly out of the body,
#Bullets are still in the body.
*You missed an entrance or exit,
#"Tandem bullets" -- two bullets entered (or exited) at the same place.
**Places to look:
#Secondary projectile -- a bullet hit something, e.g. bone, and made it fly out of the body.
***Below chin (common in suicides),
#Pathologist missed an entrance ''or'' exit.
***In mouth (common in suicides),
#*Places to look:
***Back,
#**Below chin (common in suicides).
*** ... anywhere the sun don't shine.
#**In the mouth (common in suicides).
#**Ears.
#**Back.
 
=="Sites of election" (suicide)==
Common places where people shoot themselves:<ref name=pmid1398378>{{cite journal |author=Rouse D, Dunn L |title=Firearm fatalities |journal=Forensic Sci. Int. |volume=56 |issue=1 |pages=59–64 |year=1992 |month=September |pmid=1398378 |doi= |url=}}</ref>
*Mouth.
*Temple.
*Left chest.
*Below the chin.


==Firearm projectiles==
==Firearm projectiles==
[[Image:260529196 232ebabc57 bBalleIncendiaire.jpg|thumb|200px|X-rays are useful for locating bullets. (WC)]]
===Evidence===
===Evidence===
*Bullets are often good evidence:
*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.
**The calibre (size) and markings from the barrel (on handgun/rifle projectiles) allow it to be matched to the weapon that fired it.
**Thus, all projectiles are recovered from a body... and it is routinue to X-ray all gunshot victims.
**Thus, all projectiles are recovered from a body... and it is routine to X-ray all gunshot victims.


===Classification===
===Classification===
Two broad groups:
Two broad groups:
*Shotgun projectiles.<ref name=HoFP147>{{Ref HoFP|147}}</ref>
*Shotgun projectiles.<ref name=HoFP147>{{Ref HoFP|147}}</ref>
**Many small pellets.
**Buckshot - usu. 7-9 pellets, typically 6-9 mm (diameter).
***Birdshot - smaller.
**Birdshot - many pellets, typically 2-5 mm (diameter).
***Buckshot - larger.
**Slug - one large bullet; may be confused with a (high power) rifle projectile.
 
*Handgun/rifle projectiles.
*Handgun/rifle projectiles.
**Similar in size to the barrel - large when compared to shotgun projectiles.
**Similar in size to the barrel - large when compared to shotgun projectiles.
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====Subclassification====
====Subclassification====
*Rifled projectile are often group by diameter, e.g. ".22 caliber" (~5.6 mm).
*Rifled projectile are often group by diameter, e.g. "22 caliber" is 0.22 inches (~5.6 mm).


==Entrance wounds==
==Entrance wounds==
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*Circular/round defect --especially if the projectile strikes at a right angle to the surface.
*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.
**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).
*An [[abrasion]], or scraping, --concentric or eccentric-- usually surrounds a deep wound (key feature -- used to differentiate from exit wounds).
**Eccentric abrasion suggest directionality.
**Eccentric abrasion suggest directionality.
*Usually smaller than exit wounds.
*Usually smaller than exit wounds.
**In skull the inner table defect is typically larger than outer table defect ("internal bevel").
**In skull the inner table defect is typically larger than outer table defect ("internal bevel").


Atypical entrance wounds:
===Atypical entrance wounds===
*Irregular (non-circular/non-elliptical) margin.
*Irregular (non-circular/non-elliptical) margin.
**May be due to close range/contact.
**May be due to close range/contact.
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**Bullet ricochets --hits other object before hitting target, gun defective -- bullet's long axis doesn't coincide with its velocity vector.
**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/>
***Classically results in a "D-shaped" wound.<ref name=denton/>
===Images===
====Abdomen====
<gallery>
Image:Single_gunshot_abdomen.jpg | Entrance wound - abdomen. (WC)
</gallery>
====Ceramic plates (experimental)====
<gallery>
Image: Experimental gunshot entrance wound - dist to target 0 inch.jpg | Exp. GSW, ent. contact (WC)
Image: Experimental gunshot entrance wound - dist to target 1 inch.jpg | Exp. GSW, ent. 1" (WC)
Image: Experimental gunshot entrance wound - dist to target 3 inch.jpg | Exp. GSW, ent. 3" (WC)
Image: Experimental gunshot entrance wound - dist to target 6 inch.jpg | Exp. GSW, ent. 6" (WC)
Image: Experimental gunshot entrance wound - dist to target 25 inch.jpg | Exp. GSW, ent. 25" (WC)
</gallery>


==Exit wounds==
==Exit wounds==
Characteristics:
Characteristics:
*Usually bigger than entrance wounds.
*Usually bigger than entrance wounds.
*Morphologic shape -- variable.
*Morphologic shape -- variable/irregular.
**Round, stellate, ovoid.
**May be : stellate, ovoid, round.
*NO abrasion at wound margin (key feature).
**Looks like it may be easily approximated with sutures -- unlike a typical entrance wound.
*NO abrasion at wound margin - '''key feature'''.
*In skull -- outer table defect typically larger than inner table defect (external beveling).
*In skull -- outer table defect typically larger than inner table defect (external beveling).


Atypical exit wounds:
===Atypical exit wounds===
*"Shored" exit wounds.
"Shored" exit wounds:
**Exit defect created whilst surface supported/adjacent to firm surface.
*Exit defect created whilst surface supported/adjacent to firm surface.
**Supporting surface may lead to abrasion.
*Supporting surface may lead to abrasion.
**May appear to be an entrance wound.
*May appear to be an entrance wound.
 
===Images===
<gallery>
Image:Gunshot_skull.jpg|Exit wound. (WC)
Image:Experimental gunshot exit wound.jpg |Experimental gunshot exit wound. (WC)
</gallery>


==Special entrance/exit wounds==
==Special entrance/exit wounds==
*Keyed wounds.
Keyed wounds:
**Combination entrance/exit wounds -- result from a bullet grazing the victim.
*Combination entrance/exit wounds -- result from a bullet grazing the victim.
*Attached skin tags can give directionality;<ref name=pmid6699600>{{Cite journal  | last1 = Dixon | first1 = DS. | title = Determination of direction of fire from graze gunshot wounds of internal organs. | journal = J Forensic Sci | volume = 29 | issue = 1 | pages = 331-5 | month = Jan | year = 1984 | doi =  | PMID = 6699600 }}</ref> they are classically found at the aspect of the wound distant from the projectile's origin.
**The University of Utah describes it as:<ref>URL: [http://library.med.utah.edu/WebPath/TUTORIAL/GUNS/GUNINJ.html http://library.med.utah.edu/WebPath/TUTORIAL/GUNS/GUNINJ.html]. Accessed on: 6 March 2012.</ref>
::''Characteristically, the side of the <nowiki>[skin]</nowiki> tag demonstrating a laceration is the side of the projection toward the weapon.''


==Distance of shooter==
==Distance of shooter==
Contact:
===Contact===
*Muzzle impression.
*Muzzle impression.
*Stellate splitting/tearing of the skin -- especially if it overlies a bony surface.
*Stellate splitting/tearing of the skin -- especially if it overlies a bony surface.
*Soot/gun powder residue - deep in the wound.
*Soot/gun powder residue - deep in the wound.


Close range:
===Close range===
*Stippling (tattooing) - punctate abrasions around the entrance wound.<ref name=Ref_HoFP135>{{Ref HoFP|135</ref>
*Stippling (tattooing) - punctate abrasions around the entrance wound.<ref name=Ref_HoFP135>{{Ref HoFP|135}}</ref>
**Suggests a distance <= 60 cm (rim fire cartridge), <= 90-120 cm (centrefire cartridge).<ref name=Ref_HoFP135>{{Ref HoFP|135</ref>
**Suggests a distance > 1 cm ''and'' <= 60 cm (rim fire cartridge), > 1 cm ''and'' <= 90-120 cm (centrefire cartridge).<ref name=Ref_HoFP139>{{Ref HoFP|139}}</ref>
*Soot/gun powder residue - dirt at the entrance, can be wiped-off.
*Soot/gun powder residue - dirt at the entrance, can be wiped-off.
*Scalloped border/edge in shotgun wound.


Distant:
===Intermediate===
*Stippling.
*No soot.
 
Shotgun:
*"Satellite" wounds.
*Wad marks - typically have sharp edges +/- sharp corners.
 
===Indeterminate/Distant===
:Previously known as '''''distant''''' for non-shotguns, as this is the pattern seen if a shooter is far from the victim.
*No soot.
*No soot.
*No stippling.
*No stippling.


Note:  
Notes:  
*Absence of soot & stippling does '''not exclude''' near range -- may be assoc. with clothing or intermediate target separated from the victim post-injury.
*Absence of soot & stippling does '''not exclude''' near range; the lack of soot and stippling may be explained by clothing ''or'' an '''intermediate target''' that the projectile travelled through prior to striking the victim.
*'''''Intermediate''''' should '''not''' be confused with '''''indeterminate'''''.
 
===Summary tables===
Summary table - hand gun entry wounds:
{| class="wikitable sortable"
!Distance
!Skin splitting
!Soot
!Stippling
!Other
|-
| Contact
| +/- (only if to head)
| + (in wound)
| + (in wound)
| muzzle imprint
|-
| Near contact
| -
| + (in & around wound)
| +
| no muzzle imprint
|-
| Intermediate
| -
| -
| +
| should not be confused with ''intermediate target''
|-
| Indeterminate
| -
| -
| -
| previous known as ''distant''
|}
 
Summary table - shot gun entry wounds:
{| class="wikitable sortable"
!Distance
!Skin splitting
!Soot
!Stippling
!Projectile topography
!Wad mark
|-
|Contact
| +/- (only if to head)
| + (in wound)
| + (in wound)
| round
| -
|-
|Near contact
| -
| + (in & around wound
| + (in & around wound)
| round with scalloped border
| -
|-
|Intermediate
| -
| -
| +
| round with scalloped border + "satellite" bullets
| +/-
|-
|Distant
| -
| -
| -
| scattered, multiple round-same size
| -
|}


==Injury severity due to GSWs==
==Injury severity due to GSWs==
The damage of a projectile depends on:
The damage of a projectile depends on:
*Where the bullet strike, e.g. ascending aorta vs. brain vs. tibia vs. gluteus maximus.
*Where the bullet strikes, e.g. ascending aorta vs. brain vs. tibia vs. gluteus maximus.
*Kinetic energy of the bullet.
*Kinetic energy of the bullet.
**Ek=1/2*m*v^2.
**<math>E_k=\frac{1}{2}mv^2</math>
***Velocity is more important -- as it is squared (duh).
***Velocity is more important -- as it is squared (duh).
*Cavitation effect; temporary cavity formation.<ref name=pmid19644779>{{cite journal |author=Maiden N |title=Ballistics reviews: mechanisms of bullet wound trauma |journal=Forensic Sci Med Pathol |volume=5 |issue=3 |pages=204–9 |year=2009 |pmid=19644779 |doi=10.1007/s12024-009-9096-6 |url=}}</ref>
*Cavitation effect; temporary cavity formation.<ref name=pmid19644779>{{cite journal |author=Maiden N |title=Ballistics reviews: mechanisms of bullet wound trauma |journal=Forensic Sci Med Pathol |volume=5 |issue=3 |pages=204–9 |year=2009 |pmid=19644779 |doi=10.1007/s12024-009-9096-6 |url=}}</ref>
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[[Category:Forensic pathology]]
[[Category:Forensic pathology]]
<!-- [[Category:Diagnosis]] -- in 'Gunshot wound' -->
Michael
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