Firearm Flashcards
(21 cards)
Def of weapon
An instrument discharging missile due to force of gases produced by burning of propellant in closed space
Parts of a weapon
1- hand grib
2- barrel
3- action ( بيت النار)
4- muzzle
Types of weapon
1- rifled
Short( 25 cm ) : -non automatic: revolver
-Semi automatic : pistol
Long (100 cm) : in military/ hunting
-non automatic: single bullet on pulling the trigger
-Automatic : group of bullets within seconds on pulling the trigger
2- non rifled
-Ghaffir
- military
- country gunshot ( homemade)
- sporting gun : double or single barrel
Parts of rifled weapon
- grooves ( depression)
- ridges ( land)
Alternating in spiral pattern
Why making rifled weapon
It allows rational spin that increases
- velocity
- range of firing
-power of penetration
- stability by overcoming resistance of air , gravity
What is rifling marks
Scratchs to the bullet that helps in identification of the weapon used
Cartidge ?
Rifled
1- missile ( projectile )
2- propellant ( gun powder)
3- base
4- percussion cap
5- case ( cylinder)
Non rifled
1- external wad
2- internal wad
3- shots
2- propellant ( gun powder)
3- base
4- percussion cap
5- case ( cylinder)
Missile = bullet in rifled
= wads and shots in non rifled
Sequence of events after firing
1- light : muzzle flash first then sound of the firing
2-explosive gases of missile causing tears , pinkish discolouration at the inlet ( 15 cm far)
3- flames causing burning of skin , hair
4- smoke causing blackening ( soot ) sround the inlet
5- unburnt powder particles causing ttatowing around the inlet
Estimation of firing distance
1- powder marks
- THey include burning , blackening, tattoing around the inlet
- burning : of cloths , skin , hair ( comma shaped , singed )
- blackening : soot around the inlet ( can be wiped out )
- tattoing : redish brwon punctered lesions around inlet ( can’t be wiped out )
- burning = half of barrel
- blackening = 1 for short
= 1 for long ( smokeless)
= 1,5 for long ( black powder) - tattooing = 2 for short
= 2 for long ( smokeless)
= 3 for long ( black powder)
MLI
1- diagnosis for firarm injuries
2- diagnosis for type of powder
3- differentiation between inlet , exit
4- estimation for distance
5- determination of direction
Estimation of distance 2
• projectile
- shots
The shots According to distance
1m ~> central hole 2 cm in dm
2m ~> smaller central hole with small dispersion of 4 cm in dm
3m ~> smaller central hole with dispersion of 9 cm in dm
4m ~> no holes , full dispersion of 16 cm in dm
10m ~> dispersion area of 60 cm in dm
20 m ~> full body is covered with shots
50 m ~> lose their penetration power & falls down
- wads
External wads
*Skin penetration at 1 m - circukar abrasion within 1:3 m
Internal wads
* skin penetration at 3 m
* curcular abrasion within 3:10 m
• MLI
- diagnosis of firearm injuries
- differentiation between inlet & exit
- identification of weapon used
- estimation of distance
- identification of weapon bore
- bullets
- causes single hole
- distance is indicated from degree of penetration
Def of firearm injury
- produced by missile
- may be accidental, suicidal, homocidal
- shows characters depending on
- type of weapon
- firing distance
- firing direction
General characters of firearm injury
1- presence of inlet , exit
2- loss of substance especially at entrance due to + velocity , spinning movement , heat effects
3- presence of powder marks
The inlets according to distance
• in contact :
Shape : lacerated or star or crociuate due gas expansion
Charc. : pink colour ( COHB)
Muzzle print
Powder marks (3)
Abrasion collar
Bullet wipe ( no ring )
• close
: 25 cm in short , 1,5 m in long
Shape : round or oval
Charc. : powder marks ( blackening , tattooing)
Abrasion collar
Bullet wipe ( soiling ring)
• intermediate
: 50 cm in short , 3 m in long
Shape : round or oval
Charc. : powder marks ( tattooing is pathognomonic )
Abrasion collar
Bullet wipe ( soiling ring )
• distant
: out tattooing range
Shape : round or oval
Charc. : abarasion collar
Bullet wipe ( soling ring )
Compare between inlet , exit
Inlet
•Presence : usually except if it passes through body orifice ( mouth , ear)
• size : small except
* contact firing
* shots ( before dispersion)
* oblique
* contact firing& ricochet bullet
• loss of substance: more
• edge : more regular except in
- contact firing
- corregated area
Inverted except
- contact firing
- fattay area
- putrefaction
• powder marks : present except in
- distant firing
- ricochet bullet
- cloths ( intervening)
• abrasion collar : present
• bullet wipe : present
Exit
•Presence: usually except if
- retained in body
- passes through body orifice
- scattered through tissues
• size : large
• loss sustance : less
• edges : less regular
Everted except if there is supported exit
• powder marks : absent
• abrasion collar : absent
• bullet wipe : absent
Whan can be 1 inlet with multiple exits ?
1- near shots ( non rifled ) firing
2- if the missile shatter bone and bony fragments passes out acting as extra missiles
Determination of the direction
1- peripendiculaf firing :
- circular inlet surrounded by powder marks in a circular fashion
2- oblique firing :
- oval inlet and the powder marks are condensed in eccentric fashion
3- tangential firing :
- tract with powder marks being condensed at the beginning of tract
4- usually the inlet is opposite to exit thus drawing an imaginary line points to the position of assailant , however, bullet may alter due striking bone and cant be opposite to the exit and bullet track may not be linear
injury related to special types of missile
1- plastic and rubber projectile
• are designed to weakens not to kill
• are used by police , security force for riot control
• they can cause lacerations, fractures sometimes penetration to soft tissues rg : eye globe
2- country made gunshot
- it cause tissue destruction and irregular shape as the cartidge ate filled with homemade shots made of lead , nails , stones , metal scraps
3- blank shells
- the cartidge are filled with small amout of powder enough to produce flash and sound of a real load with no projectile in it
- it is not that dangerous unless its close due the gush of gases damage
Talk about fabricated firearm
Def : superficial injury with missile inside it and the margins are blackened
- there is no loss of substances
- no matching between powder marks and the distance told
- the cloths are spared
What is doctors duty in firearm injury
(7)
1- emergency treatment with life saving measures
2- antibiotics regulary as contamination is suspected in gunshot injuries
3- report the police
4- documentation:
- photography with measuring scale
- sketches
- primary wound report is mandatory
5- radiologic imaging
X ray : to see retained missiles, fractures, bullet track
CT : is superior as it shows multiple views with higher resolution
6- any missile or forgien bodies as wads must be preserved first further investigation
6- clothes are preserved and examined for any defects or gunshot residues
What is gunshot residues , where can it be
1- burnt and unburnt gun powder
2-
* hands of assailant
* cloths of him
* cloths of victim
* around inlet
* any target material in the scene
* swab in barrel of fired weapob
* in fired cartidges
Def of
- abrasion collar
- bullet wipe
1- marginal abrasions as the missile abrades the skin on penetration
2- lubricant and greases on bullet surface wiped off on the wound edges
