Firearm injuries
Gunshot wound of bone
Bone fragments form secondary projectiles; bone may exit the body; bone often indicates the direction of bullet by beveling; entrance wound is round, oval, punched out and sharp edged and the exit wound is excavated in a cone like manner *(beveling outward indicates exit wound)*
Types of Range of fire
Contact, Close and Distant range
Types of Entrance Wounds
Graze wound, tangential, shored, reentrance
Gunpowder
Smokeless, coated (shiny black), uncoated (green), ball, flattened ball, disk, flake, will not travel beyond 3 feet, tattooing (actually imbeds in the skin) stippling (leave injury but nothing is imbedded) and pseudostippling (skin injuries not produced by gunpowder); more irregular; rare to have in an exit wound
Hard contact gunshot wound
Tissue surrounding the wound may have a cherry red color from carboxhemoglobin, wounds may be stellate or cruciform and may have a muzzle imprint
Soot
Vaporized carbon, contains metal from from primer, bullet and cartridge case, lighter than gunpowder, doesn't travel as far as gunshot powder (no more than roughly 12 inches), can be removed
Perforating Gunshot wound
a wound where the projectile exits the body
Penetrating Gunshot wound
a wound where the projectile is still in the body
Gunshot wound of Bone
bone perforation depends on velocity of the bullet, bullet construction, weight of the bullet, angle of interaction between bullet and bone and type of bone;
Reentrance wound
bullet passes through one body part and reenters another body part; usually from perforating the arm and entering the thorax; typically large irregular wound with irregular abrasion ring
third degree wounds to the skull
bullet perforates skull in the center of the wound
Keyhole wounds to the skull
bullets striking at an shallow angle produce a wound with one edge having characteristics of an entrance wound while the other edge has external beveling characteristic of an exit wound
Sodium rhodizonate test
detects lead residue around an entrance defect; lead produces a bright pink reaction; not used to determine exact range and must be performed after greiss test.
Severity of wounds
determined by size of temporary cavity; directly related to the amount of kinetic energy lost in the tissue.
Hard contact gunshot wound
edges of the wound are seared by hot gases and blackened soot; soot and gunpowder within the wound tract; skin surrounds the muzzle, tearing of skin and surrounding skin may be blackened by soot
Graze wound
elongated area of abrasion
Shored entrance wound
entrance is supported by another portion of the body; usually seen involving the arm and the chest
psuedo soot
fingerprint dusting powder; graphite-bullet striking pencils; asphalt-bullet striking ground and dried edges of an entrance wound
second degree wounds to the skull
fracture of inner table
distant range wounds to the skull
fractures produced by pressure from the temporary cavity formation
contact wounds to the skull
gases enter cranium and expand
Energy dispersive x-ray
gives an approximation of range.
Bullet wipe
gray-black rim around an entrance wound; material wipes off on clothing; does not indicate range of fire; can determine entrance wound from exit wound and may be to determine sequence of fire. *Will not be present on an exit wound.*
gunshot wounds through clothing
gunpowder and soot are deposited on clothing; tears in clothing; melting through polyester; cylinder gap and bullet wipe.
Types of bullet wounds to the skull
gutter wounds, first degree, second degree, third degree, keyhole wounds, contact wounds, distance range wounds
Types of contact gunshot wounds
hard contact, loose contact, angled contact, incomplete contact and near contact
Tangential wound
injury into the subcutaneous tissue; area of abrasion at entrance; torn margins of skin point in the direction the bullet moved
X-rays
location of bullet and fragments; lead snowstorm equals centerfire bullets; x-ray may distort size; can't determine range in a shot gun wound due to billard ball effect; may need to x-ray clothing.
Loose contact gunshot wound
muzzle in light contact with skin, soot and gunpowder deposited in a band around the wound and muzzle imprint usually not present
Near contact gunshot wound
muzzle is close but not in contact with the skin; gray zone between contact and intermediate range wounds; too close for gunpowder stipple to be produced.
Angled contact gunshot wound
muzzle is not in complete contact; gas and soot produce an eccentric pattern; entrance wound is at the base of the eccentric pattern.
Close range-intermediate range gunshot wounds
muzzle of the gun is away from the body at the time of discharge; muzzle is still close enough to produce gunpowder stippling and possibly soot deposition; stipple can't be wiped away but soot can.
Distant range gunshot wounds
muzzle of the gun is far enough from the body so that no soot or gunpowder is deposited in the body; range determination can't be made and bullets from 5, 50 or 500 produce as type of entrance wound.
incomplete contact gunshot wound
occurs when the body surface is not flat; often seen in the head; elongated area of searing, gunpowder and soot and on side opposite of the muzzle; a hybrid between a close range and a contact wound.
first degree wounds to the skull
outer table grooved by bullet
Psuedo gunpowder stipple
punctate abrasions produced by objects other than gunpowder; glass, fragmented bullet and homemade silencers; post-mortem insect activity, hemorrhage in hair follicles, medical intervention and petechiae
Shored exit wound
results when skin is supported by a surface when the bullet exits. The skin surrounding the wound has a broad area of abrasion
Characteristics of gunshot wounds to the skull
secondary fractures due to intracranial pressure waves which depends on range of fire and kinetic energy; most common in the orbital plates and more common in contact wounds of the head due to gas discharge
Cylinder gap
seen when cloth is wrapped around a revolver; L or V shaped blackened area on the cloth; produced when soot and gases escape from the cylinder gap and can determine the barrel length.
Gunpowder stippling
size, density and pattern depends on gunpowder type, barrel and length; closer range-narrower more dense pattern; greater range-wider, less dense pattern; also depends on caliber, individual weapon and intermediary objects
Bullet emboli
small caliber and low velocity bullets; usually involve the aorta or heart; may embolize to legs, pelvis and may regurgitate or aspirate bullet.
Near contact angled gunshot wound
soot radiates outward from the muzzle; bulk of the ozone is on the same side as the muzzle.
gutter wounds to the skull
tangential wounds
Contact range of fire
tight or loose
Ricochet bullets
tumble in the air producing larger more irregular wounds ( increases yaw); one surface of recovered bullet is flattened and may fragment and pepper the body.
Modified Greiss test
used on clothing; used to determine range of fire and detects nitrites as orange spots.
Entrance wound
usually round, oval or elliptical. Usually has a ring of abrasion. May have microtears ; especially in high velocity center fire rifle bullets. The margins can't be reapproximated
Entrance wound
variation in the abrasion ring depends on direction that the bullet entered. Palms and soles may not have abrasions ring. Distance range wounds may be stellate especially over bony prominence of the head. Can resemble exit wounds or contact wounds
Exit wounds
various shapes, rare to have surrounding abrasion, tissue is not lost and margins can be reapproximated; irregular nature of wounds, shape and size does not correlate with bullet type, size and shape may depend on the location of the wound, lax skin-slit like and tightly stretched skin- stellate
Intermediary targets
when bullet passes through an object before striking the person; yaw of the bullet increases producing an atypical entrance wound; may have bullet deformation; bullet may fragment producing more than one entrance wound and the pattern of the object may be imprinted on the bullet