Gunshot wounds, Shotgun wounds

what are the 3 types?

***1) Contact (tight or loose)- will produce star due to gas expansion 2) Close/Intermediate range - interchangeable items 3) Distant range

What is Range of Fire?

***Range of fire- how far the muzzle of the weapon is to the person/or their clothing.

The severity of a gunshot wound is determined by the size of the __________ which depends on the amount of ______ lost in tissue

*1) Temporary cavity* which depends on the amount of *2) kinetic energy* lost in tissue

*Soot vs gunpowder

*Soot*- Lighter, won't tavel beyond 12in, doesn't get embedded in skin, removed by hot water or hydrogen peroxide, don't travel *Gunpowder*- can travel up to 3ft, can get embedded in skin, can't be wiped away, smokeless,

Range of fire-distant range

-4ft: main entrance surrounded by satellite wounds -6-7ft: cuff of satellite wounds -10ft: great variation depending on ammo, choke and range

What are Reentrance Wounds? How do they look?

-Bullet passes through one body part and reenters elsewhere. -Usually from bullet perforating the arm and entering the thorax -Typically has large irregular wound with an irregular abrasion ring, like in chest. -Often has contusions/bruise and large rings of abrasions due to inc. in yaw

GP stippling depends on (3)

-Caliber, -Individual weapon, -Intermediary objects (impt b/c if shooting through an obj the person won't have any gp on them b/c it will be on the obj not on the person)

Modified Greiss Test

-Checks for gp. -Chemical test used on CLOTHING to DETECT NITRATES (orange). Used to determine range of fire.

Lead snowstorm

-Due to high velocity center fire bullets usually found in long guns -The bullet tends to tumble and fragment through the body and the lead will come out of the base of the bullet producing this "lead snowstorm" on X-ray.

Energy-dispersive x-ray

-EDGES OF ENTRANCE ANALYZED FOR CU, ANTIMONY, BARIUM, AND PB -distribution of residue mapped out in semi quantitative manner -Gives approximation of range of fire, not readily available .

Shored Entrance Wound

-Entrance is supported by another portion of the body. -Usually seen in reentrance wounds involving arm & chest. ex) A gun shot through the arm into the chest. The chest is supported by the arm being in contact with it - shored entrance wound can look like reentrance wound due to support

Range of fire-distance range

-Entrance wound increases in size w/ distance -by 3ft: scalloped margins

**What is a Shored Exit Wound? What kind of abrasion does this create?

-Exit wound that results when skin is supported by a surface/obj when the bullet exits (ie; a wall/ground). -the skin surrounding the wound has a broad area of abrasion b/c as the bullet goes through it slaps the skin surrounding the exit against the wall czing the abrasion around the exit wound -This creates a broad area of abrasion Ex)someone being shot the on ground. Bullet slaps skin against the ground czing the abrasions. this is an exception to the exit wound having an abrasion

range of fire close range wounds

-Gp stipple, especially in sawed of SG -Depends on type of powder used and barrel length -stipple may be out to 3ft

Bullet wipe what is it?

-Gray-black rim around an entrance *hole* (not wound) made by lead and full jacketed bullet. Not seen on the body. But can be seen on light colored clothing

Skull Gunshot wounds: Contact wounds

-Gunshot wound where gases enter the cranium and expand -more likely to have deformation of soft tissue, as wel as fragments and fxs of skull

What are the 6 types of contact GSWs?

-Hard contact -Loose contact -Angled contact -Incomplete contact -Near contact -Near contact angled wounds

Exit Wound Characteristics (4)

-More variable shape -Rarely have surrounding abrasions since its pushing skin outward -Tissue isn't lost, so margins can be reapproximated - Heal better and are easier to suture

Incomplete Contact gunshot wounds

-Occurs when a body surface is not flat (usually head or shoulder). Muzzle is in contact with portion of the head. -Characterized by elongated area of searing, gp & soot on the opp. side of the muzzle. (eccentrically distributed)

Cylinder Gap

-Seen when cloth is wrapped around a revolver and fired. -Can see L or V shaped blackened area on cloth. -If there is no gap, it often means a semi-automatic handgun was used.

Near Contact Angeled Wounds

-Soot radiates outward from muzzle -Bulk of the zone is on the same side as muzzle -Opposite of pattern in angled contact wounds

Range of fire close range wounds

-Stipple less than handgun at same distance -wad and or cup may strike body or be deposited in wound -wad/cup injury: petal marks, PETALS may bend back at diff distances

Sodium Rhodizonate Test how does it differ from Greiss test?

-Used to detect LEAD residues around ENTRANCE defect (pink). -Most lead arises from PRIMER. -some lead around from bullet or from residue in the barrel -Must be done after the Greiss test. - Lead produces a bright pink rxn -NOT USED TO DETERMINE EXACT RANGE OF FIRE -must be performed after

Entrance wounds Characteristics (4)

-Usually round, oval, elliptical -Ring of abrasion around it -May have microtears if a high velocity rifle is used -Margins can not be reapproximated

*Soot

-Vaporized carbon that -contains metal from primer, bullet, and cartridge case. - many factors determine pattern and range -propellant, angle, barrel length, caliber, weapon type -Longer barrel smaller and denser *Will not travel beyond 12 inches.* Very light, so it *can be wiped away* or removed by hot water/hydrogen peroxide.

Bone perforation depends on (5)

-Velocity of bullet , -Bullet construction, -Wt of bullet, -Angle of interaction between bullet and bone, -Type of bone

Intermediary Targets

-When a bullet passes through an object before striking a person. -The object may fragment & strike the person producing various injuries. -This increases yaw to create an atypical/irregular entrance wounds.*** - may have bullet deformation also contributing to an atypical entrance wound -bullet may fragment producing more then one entrance wound -Pattern of obj may be imprinted on bullet (impt to look at what it strikes)

Loss of KE

-amt of KE in a bullet at the time of impact depends on the mass and velocity of the bullet -angle of yaw of a bullet at the time of impact -type of bullet -type of tissue involved

**GP

-ball, will travel the furthest -flattened ball -disk, flake -gp generally will not travel beyond 3ft -gp tattooing -gp stippling -pseudostippling

What does the bone often indicate

-direction of bullet by beveling especially in the skull -bevels in the direction the bullet was going

Skull Gunshot wounds: Distant range wounds

-fractures produced by pressure from the temporary cavity formation -especially if its a high velocity round like if its a rifle, b/c the faster the round the more KE

What's impt to note w/ intraoral gsw

-hard palate will show loose contact, which is where you will see distinct pattern of gp and soot -most are suicidal in nature

Contact SGW of trunk

-less deformation than head wounds because gases can expand in abdomen & chest (less than in head) -less gp & soot because barrel is longer that in GSW -impression from muzzle/muzzle stamp -chest and abd expand -loose contact: circular area of soot and Gp around the wound -Cherry red discoloration

Near Contact Gunshot Wound

-muzzle is close to but not in contact w/ skin. Too close for individual gunpowder stipple to be seen. -You'll see tight band of gp and soot around entrance wound. This is a gray zone between contact and intermediate range wounds) -overlap in appearance btwn near and loose contact wounds -too close for GP stipple to be produced

Loose Contact Gunshot wound

-muzzle is in light contact with skin. -Soot and gunpowder deposited in a ring like/band around the entrance wound. -Muzzle imprint is not usually present.

Angled Contact Gunshot Wound

-muzzle is not in complete contact w/ skin but very close. -Gas and soot will produce eccentric pattern**. -Entrance wound is at base of eccentric pattern.

Close/Intermediate range Gunshot Wounds

-muzzle of gun is away from the body at time of d/c, not in contact w/ body -muzzle is still close enough to produce gp stippling and possibly soot deposition on clothing or skin

Distant range wounds

-muzzle of the gun is far enough from the body so that no soot or gunpowder is deposited on the body -expect range depends on the particular weapon and ammunition - range determination can not be made for distant gunshot wounds bullets fired from 5,50, or 500ft produce the same type of entrance wounds

Projectiles

-never attempt to estimate caliber of a bullet from an xray or autopsy -don't handle bullets w/ metal intruments b/c it can disturb the bullet markings -don't engrave your initials on the bullet

What types of wounds are produced by wads and shot cups

-produce abrasions or petal marks adj to the entrance wound at ranges of 1-3 ft -wad or cup may enter the wound at close range

When is the cylinder gap produced

-produced when soot and gases escape from the cylinder gap -can determine the barrel length by measuring the distance btwn entrance defect and the cylinder gap

Contact SGW head

-shreds brain, pressure waves increase severity of wounds & ejects brain tissue -Gas enters closed head chamber, rapidly expands, skull fx to relieve pressure causes head to expand - may have GP on nondominant hand, especially if suicide intraoral wound usually have tears at corner of mouth intraoral: GP and soot on palate and tongue - charge of shot entering the skull -gas from propellant - wad or cup in the wound -inner table of skull may have indentations from pellets

What does GP stippling depend on

-size and density of GP type, barrel length -the longer the barrel the more likely the GP is to be burned -closer range: narrower more dense pattern -greater range: wider, less dense pattern

Bullet Emboli what kind of bullets usually cause this?

-small caliber, low-velocity bullets -wounds usually involve aorta or heart (have access to large bv) -may embolize to the legs, pelvis, brain, etc. -May be regurgitated/aspirated of bullets involving the oral cavity or respiratory tree (can throw up, cough up bullet).

distinguish suicidal and intraoral gsw

-suicidal intraoral gsw- proceed in backward, upwards trajectory bullet will come out of top of head homicidal intraoral gsw more likely to be horizontal in its trajectory, so the bullet will come out of the back of the head

Range of fire distant range

-weapons w/ the same choke may produce diff patterns at the same range -diff brands of ammo can produce diff patterns at the same range -need to use the actual weapon and the same brand of ammo to obtain the most accurate results

----SHOTGUN WOUNDS -------

...

Size & density of stippling pattern depends on ...(2)

1) Gunpowder type 2) Barrel length

What is a Tangential Wound? How can you determine where bullet came from ?

1) Gunshot wound into subcutaneous (innermost) tissue, with an area of abrasion at the entrance and torn margins of skin pt in the direction the bullet moved. 3) similar to graze wound but deeper 4) have reverse christmas tree pattern and the apices of the torn areas pt toward the direction that the bullet came 5) goes from left to right b/c the abrasions are on the left when it strikes the skin then it exits then you have the apices of the triangle which point to the left in the pic

Gauge

1) describes the caliber of the shotgun 2) equals the number of lead balls of the bore diameter that makes up a lb**** 3)12 gauge: 12 Pb balls to make one lb 4) the larger the gauge the smaller the bore diameter

Exit wounds vs entrance wounds

1) exit wounds can be reapproximated 2) entrance wounds can't be reapproximated due to tissue loss

Range of fire-contact wounds

1) massive deformation especially when they involve the head b/c there is massive expelling of gas 2) muzzle stamp present

Choke

1) partial constriction of the bore at its muzzle 2)controls shot pattern and helps w/ controlling range of fire

How are entrance wounds described

1) round, oval, elliptical 2) usually has a ring of abrasion surrounding it (b/c as the bullet comes from the outside in it scrapes the epidermis of surrounding skin as it enters the body) 3)may have microtears: esp in high velocity centerfire rifle bullets 4) margeins can't be reapproximated (due to tissue loss)

*Entrance wounds: Distant range wounds may be what shape?

1)*stellate/star shaped* especially over bony (from high velocity round) prominence of head Note: resemble exit wounds or contact wounds. 2) Size and shape of wound is not enough to distinguish entrance or exit wounds or range of fire

Hard Contact Gunshot Wound

1)Gunshot Wound where the gun is placed firmly against skin. The edges of the wound are seared by hot gas and blackened by soot. 2)Gunpowder/ soot are found within the wound tract not around the wound b/c the seal is tight. Tissue may have cherry red color from carboxyhemoglobin, which is d/c from weapon. Rarely accidental due to suicide. Wound may be stellate or cruciform. Muzzle imprint usually present

What are the 4 types of choke

1)full choke 2)modified choke 3)improved cylinder 4)cylinder

handguns can deposit GP and Soot at what distance

12in

handguns can deposit soot at what distance

12in

handguns can deposit G at what distance

3ft

Past what distance will handguns no deposit gunpowder

3ft. if beyond 3ft and can't see any stipple or gp then you are at distant range

Billiard ball effect Can you determine range of fire?

As shotgun pellets enter the body, they hit each other and disperse. So you cannot determine range of fire in shotgun injury

*Yaw

Bullet instability as it enters a body. The rotation of the nose of the bullet away from the line of flight.

What are Ricochet Bullets? What characteristic is indicative of a ricochet bullet?

Bullets that produce larger, more irregular wounds due to tumble in air (inc. yaw). (change in trajectory of bullet; ex) bounces off something) -Characteristic: -One surface of the bullet will be flattened*. -May penetrate, but does not perforate body. -may fragment and pepper the body

what is it composed of ? (3)

Composed of soot, lubricant, metallic elements. Does not indicate range of fire

*Bullet wipe does not indicate _______ but may determine _______ & ____

Does NOT determine range of fire but CAN determine entrance from exit defect (typically don't have bullet wipe) & sequence of fire

Differentiate exit from entrance wound

Entrance wound- round, oval, punched out***, sharp edged Exit wound- excavated in cone like manner

Gunpowder can travel ____ than soot

Farther (3 ft)

What are the characteristics of SGW

Gauge, choke, range of fire, rifled or smooth bore, sawed off shotguns. You can't match up specific pellet w/ gun

Keyhole Wounds

Gunshot wound where bullets striking at a shallow angle produce a wound with one edge having characteristics of an entrance wound, whereas the other edge has characteristics of external beveling of an exit wound -fragment of bone may enter brain and become lethal

Distant Range Gunshot Wounds

Gunshot wound where the muzzle is far enough so that no soot/gunpowder is deposited on the body. (Muzzle is more than 3ft away ). Generally, no gunpowder will be travel beyond 3ft. At 4ft or 400 ft, entrance wound may look the same.

Graze wound

Gunshot wound with elongated area of abrasion. Occurs on superficial layers of skin. Difficult to determine direction.

What does the range of fire tell you

How far was the muzzle of the weapon from the victim

What causes secondary fractures in a gunshot wound to the skull?What is it dependent on? (2)

Intercranial pressure waves. Depends on range of fire and kinetic energy possessed by the bullet, -most common in orbital plates. common in contact wounds of the head due to gas discharge -also czd by high velocity weapons

how would a hard contact wound on abdomen look?

Less likely to see stellate defect because when wound isn't overlying bone, there is more room 4 gasses can expel - so the wound is round and muzzle stamp will be present due to heat of the weapon so there will be some searing

*Contact shotgun wounds show ____ stippling than handgun injuries. why?

Less; because barrel of shotgun is so long

what is it made by? (2)

Made by lead and full jacketed bullets

Close/Intermediate range of fire

Muzzle of weapon is close enough (no skin contact) to the person to deposit gunpowder on the victim (stippling)

Can you denote the timing of SGW

No

Does Shape and size of wound correlate with type of bullet? If not, what does size & shape depend on?

No, because skin is elastic However, size & shape of wound depend on location of exit wound: -lax skin vs tight areas

How can you tell the difference between old bullet & new bullets retained in body?

Old bullets are surround by scar tissue, don't have hemorrhage around & they often become oxidized in body

What should you store clothes in for evidence?

Paper bags

Pseudo-gunpowder stipple

Punctate abrasions of skin produced by objects other than gunpowder (ie; post mortem insect activity, petechiae, fragmented bullets, glass, etc). -glass: fragment often found in clothing or on skin -fragmented bullet -homemade silencers- -post mortem insect activity (ants and roach bites) -hemorrhage in hair follicles -sutures, staples -petechiae

What can scalloping help determine

Range of fire

Distant range SGW: Entrance wound increases in size with distance. By 3 feet of you see ______ margins on wound. why?

Scalloped This is because pellets are starting to separate from main pellet mass. This may help determine range of fire.

The only exit wounds that have abrasions are

Shored Exit wounds

When a bullet hits lax/loose skin (ex: neck, armpit) the exit site will look _____

Slit-like

Longer gun barrel produces _______area of soot

Smaller/Denser

When a bullet exits out of tightly-stretched skin (ex: head), the exit site will look _____

Stellate

What do injured organs tell you

Tells you what killed them. Ex hypovolemic shock. tells you what the person was doing after they were injured like could they continue to run, speak, could they return fire

What do the entrance and exit wounds help determine

The direction of the wound path

What's the impt of recovery of projectiles

They don't decompose, they can be used in identifying other crimes if they are old bullets

What can happen when Low velocity bullets strike the skull?

They strike the skull, flatten and travel between the scalp and skull, mostly the smaller caliber/velocity bullets

When do you see stellate appearance in hard contact wound?

When its tissue overlying bone

Billiard ball effect

When pellets went in they start to separate like billiard ball

Gunpowder Stippling

When unburned gunpowder grains exits the gun causing pinpoint abrasions on the skin surrounding entrance wound. Can happen when muzzle is in close range w/ person. It *cannot be wiped away*. Generally does not occur beyond 3ft.

Penetrating gunshot wound

Wound where the projectile is still in the body. Has an entrance site, no exit site. The projectile would still be in the body.

Perforating gunshot wound

Wound where the projectile leaves the body. Has an entrance and exit site.

Bullets striking at shallow angle may cause

a portion of bone to penetrate the brain & keyhole wound. bullet can sometimes just embed in some skulls b/c they are so thick

what czs GP

abrases, burns skin this czs stippling

What would you see surrounding the reentrance wound

area of abrasion and there is a bruise surrounding the wound producing a contusion due to force of passing through the arm

Why is it impt to keep clothing

b/c the clothing can have the appearance that would be expected on the skin

why's it impt to get clothing

b/c there is a bullet defect w/ surrounding GP

why is it impt to distinguish entrance vs exit wouns

b/c you want to recreate what happened. exit wounds are more variable than entrance wounds in size, shape, and configuration due to bullet tumbling breakup fragment as it goes through the body czing diff exit wounds or change in shape

is it possible to have 3 gsw in chin

beard present can cz loose contact w/ gun, rather than close contact. if the first wound doesn't hit a portion of the brain that doesn't hit a portion of the brain that will debilitate them then yes, they can have 3 gsw in the head. certain injuries will prevent certain movements

how does GP/soot appear on light background

black and gray

Describe the change in KE when bullet strikes bone

bullet can strike bone when this happens it can lose KE and increase yaw and will have a diff shape in comparison to the entrance wound that is in the chest and the arm

when a firearm is discharge besides the bullet what comes out of the weapon

burning or unburned GP, soot, flame, and gases

can't determine range of fire on skin when clothing worn

but use clothing to show how far it was fired and that can help w/ determining range of fire

What's a common location for GSW

buttock b/c you are likely to turn away and the trajectory of the bullet can go up into the body

W/ GSW in bone how can you determine order of fire

by looking at fx lines, b/c fx lines won't cross. 1st bullets are parallel. 2nd are perpendicular

Cherry red discoloration found on skin near wound may be produced due to ...

carbon monoxide -component of gasses discharged from gun

*Filler is only found in ____ range Shotgun wounds

close range -Wad, fillers can't travel too far Note: looks like white fragments

where can bullet wipe wipe off on

clothing

Tears in clothing can be seen in

contact wounds

differentiate the core and the jacket of the bullet

core has greater mass and velocity. core may be left behind and the core may leave the jacket behind and exit

Entrance wound: Variation in abrasion ring depends on...

direction that the bullet entered: concentric vs eccentric abrasion ring Depends on the angle the bullet enters the body. Note: Inc in yaw may cause eccentric abrasion. if the bullet doesn't enter at a 90 degree angle this can increase the yaw

Incomplete contact has what type of distribution

eccentric distribution of soot and gp from the opposite side of where the muzzle made contact

Exit wounds of bone will show ______

external beveling -hole on inner table of skull is smaller than hole on outer table

What can bone fragments form after being struck by bullet and what makes them so bad

form secondary projectiles as the bullet strikes bone, this can be more lethal than the bullet itself. bone can exit the body

Uncoated GP is

green or beige

What causes a keyhole wound

hitting at the curvature of the skull and entering and exiting right at the same time. can be letal due b/c fragments of the bone can enter the brain

GP stipple

impact of unburnt partially burnt or burning GP on the skin

Entrance wounds of bone will show ______

internal beveling hole on outer table of skull is smaller than whole on inner table

COntact GSW head

intraoral SG injury czs tears in the mouth and stretch injuries of the cheek. shotgun cups found in the mouth should be recovered

GSW head

intraoral shotgun injury czs massive deformation. the skull will expand multiple times b4 collapsing on itself

What is bullet wipe

its the stuff on the bullet that travels w/ the bullet, such as remnants on the bullet from the barrel or prior to being placed in the gun

What's the most impt portion of the bullet and should be collected?

jacketed portion b/c it can have lands and grooves from the firearm

what's the diff btwn the angled and loose contact wound

location of the muzzle -incomplete the muzzle is not in complete contact. against area of round bone/ tissue -angled- its not really in contact but very close

how does gp/soot appear on black background

looks grayish white

contact through polyester seen in

melting

when a revolver is used where can GP and soot be produced from?

muzzle and the cylinder gap

Can stipple be wiped away

no

Do semi-automatic weapons have a cylinder gap

no

Can you see abrasion rings on entrance wounds of palms & soles?

no you may not see abrasion ring there because of the nature of epidermis.

In contact shot gun wounds, gunpowder may be found on the _______ of the shooter

non dominant hand

what's essential to identify intraoral gsw

palate and tongue

SGW: wad/cup injury produce what type of marks?

petal marks

What weapons have larger cylinder gaps

poorly made weapons

What can a 2nd fx of the skull to the orbital plate cz?

raccoon eyes/spectacle hematomas

What do GP and soot deal w/

range of fire

Is it likely that people will develop PB poisoning from retained bullets

rare, only occurs if lead bullet is in synovial joint, bone, or vertebral disc. -can cz intranuclear inclusions in hepatocytes -many retained bullets don't do any harm and are left as trophy bullets

locate old bullets

scar tissue oxidized

Coated BP is

shiney black

shotgun shell

shot, cup, wad, gunpowder, primer

Why is there a tearing of skin in hard contact

skin surrounds muzzle -tearing of skin, b/c gases expanding outward, especially the skull and weapon - surrounding skin blackened by soot

Shotgun ______ are single projectiles that may be encased in a _______

slugs; sabot (plastic covering over slug). They may cause adjacent injuries may be from wads or sabots - have various wads -will have single large wound

When muzzle is in contact with the skull , it often produces what shape wound ?

stellate, star wound because gas is expanding outward

When are hard contact wounds seen?

suicide, due to its high lethality. Some muzzles can leave stamps called muzzle stamps

Gutter wounds of skull

tangential wounds that graze along the outer table of the skull; has 3 degrees, but don't need to know

What can you see in an intraoral shotgun injury?

tears around corner of the mouth

how would a GSW that is 4ft vs 400ft compare

they would look the same

What's typical of near contact wounds

tight band of Gp and soot around the wound

How are external wounds measured

using English system

how do shotguns fire

usually fire multiple pellets

Can soot be wiped away

yes