Difference between revisions of "Gunshot wounds"
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**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> | **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. | |||
===Intermediate=== | |||
*Shotgun: | |||
**"Satellite" wounds. | |||
**Wad marks - typically have sharp edges +/- sharp corners. | |||
===Distant=== | ===Distant=== | ||
Revision as of 13:22, 14 October 2010
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.
Accounting
Number of entrance wound should equal the number of exit wounds -- the explanation is:
- Bullets still in the body.
- "Tandem bullets" -- two bullets entered (or exited) at the same place.
- Secondary projectile -- a bullet hit something, e.g. bone, and made it fly out of the body.
- Pathologist missed an entrance or exit.
- Places to look:
- Below chin (common in suicides).
- In the mouth (common in suicides).
- Ears.
- Back.
- Places to look:
"Sites of election" (suicide)
Common places where people shoot themselves:[1]
- Mouth.
- Temple.
- Left chest.
- Below the chin.
Firearm projectiles
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.
- Thus, all projectiles are recovered from a body... and it is routinue to X-ray all gunshot victims.
Classification
Two broad groups:
- Shotgun projectiles.[2]
- Buckshot - usu. 7-9 pellets, typically 6-9 mm (diameter).
- Birdshot - many pellets, typically 2-5 mm (diameter).
- Slug - one large bullet; may be confused with a (high power) rifle projectile.
- 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).
Subclassification
- Rifled projectile are often group by diameter, e.g. ".22 caliber" (~5.6 mm).
Entrance wounds
Characteristics:[3]
- 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.[3]
- May be due to close range/contact.
Exit wounds
Characteristics:
- Usually 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 (tattooing) - punctate abrasions around the entrance wound.[4]
- Suggests a distance > 1 cm and <= 60 cm (rim fire cartridge), > 1 cm and <= 90-120 cm (centrefire cartridge).[5]
- Soot/gun powder residue - dirt at the entrance, can be wiped-off.
- Scalloped border/edge in shotgun wound.
Intermediate
- Shotgun:
- "Satellite" wounds.
- Wad marks - typically have sharp edges +/- sharp corners.
Distant
- No soot.
- No stippling.
Notes:
- 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).
- Ek=1/2*m*v^2.
- Cavitation effect; temporary cavity formation.[6]
See also
References
- ↑ Rouse D, Dunn L (September 1992). "Firearm fatalities". Forensic Sci. Int. 56 (1): 59–64. PMID 1398378.
- ↑ DiMaio, Vincent J.M.; Dana, Suzanna E. (2006). Handbook of Forensic Pathology (2nd ed.). CRC Press. pp. 147. ISBN 978-0849392870.
- ↑ 3.0 3.1 Denton JS, Segovia A, Filkins JA (September 2006). "Practical pathology of gunshot wounds". Arch. Pathol. Lab. Med. 130 (9): 1283?9. PMID 16948512. http://journals.allenpress.com/jrnlserv/?request=get-abstract&issn=0003-9985&volume=130&page=1283.
- ↑ DiMaio, Vincent J.M.; Dana, Suzanna E. (2006). Handbook of Forensic Pathology (2nd ed.). CRC Press. pp. 135. ISBN 978-0849392870.
- ↑ DiMaio, Vincent J.M.; Dana, Suzanna E. (2006). Handbook of Forensic Pathology (2nd ed.). CRC Press. pp. 139. ISBN 978-0849392870.
- ↑ Maiden N (2009). "Ballistics reviews: mechanisms of bullet wound trauma". Forensic Sci Med Pathol 5 (3): 204–9. doi:10.1007/s12024-009-9096-6. PMID 19644779.