FIREARMS AND FIREARM INJURIES

ByADEEB UL HASSAN3RD YEAR MBBS BOLAN MEDICAL COLLEGE QUETTA

Gun, auto loading, semi-automatic, 9 mm pistol, gross

Here is an auto loading, semi-

automatic pistol. The force

generated from each bullet fired

causes a new round to be

chambered from the magazine.

Gun, auto loading, semi-automatic, 9 mm pistol with clip, gross

• Here is an auto loading, semi-automatic pistol. The detachable magazine that holds 17 rounds is placed into the grip.

Gun, revolver, .38 cal, gross

• Here is a revolver, which holds six rounds. Note the gap between the cylinder in the center and the frame.

Gun, semi-automatic rifle, .308 cal, gross

• Here is a semi-automatic rifle. A rifle is a firearm with a long barrel, which gives the larger rounds more accuracy and range. The energy of the fired bullets is enormous. The .308 caliber copper jacketed bullets fired by this rifle can blow a hole in plate steel 1/4" thick.

Bullet cartridges, diagram

• Note the basic features of cartridges used in guns. The primer, when struck by the firing pin, ignites the powder. It is the residue left by the primer that is characteristic for a fired round, because it leaves traces of lead, antimony, and barium.

Gunshot residue, pattern by SEM-EDX, diagram

• The gunshot residue deposited in a gunshot wound can be detected by using scanning electron microscopy coupled with energy-dispersive x-ray microanalysis to demonstrate the characteristic elemental pattern of the primer residue with lead, antimony, and barium, typical for many cartridges, as shown in this diagram.

Common rifle and handgun cartridges, gross

• The appearances of the most common handgun and rifle rounds are shown here. In general, it is difficult to tell from the wound exactly what round was used.

Deformed bullet recovered from shooting victim, gross

• When bullets strike a target, there can be considerable deformation and fragmentation. In this case, the lead bullet has become markedly deformed and has separated from the copper jacket at the right.

Striations on bullets, gross

• Bullets fired from a gun will have "striae" (linear grooves) imparted as a consequence of traversing the barrel, and these marks help to identify the weapon. Comparison of bullets involves "class" (caliber and rifling) and "individual" characteristics based upon burrs or imperfections in the barrel, particularly the muzzle, that impart specific markings, or striae, to fired bullets. Individual characteristics are used to try and determine if a specific gun was used in a crime. The sets of bullets shown here are from the same class, but deformations in recovered bullets (the right of each pair) can complicate comparison

Bullet track in clay model, gross

• Much of the damage done by a bullet results from the tumbling motion and the cavitation in the tissue. This is the bullet track in clay of a .38 caliber round, demonstrating that the wound track is much larger than .38 inches (closer to 3 inches).

Contact range gunshot wound, gross

• This is an contact gunshot entrance wound. Since the barrel contacts the skin, the gases released by the fired round go into the subcutaneous tissue and cause the star-shaped laceration. Note also the grey-black discoloration from the soot, as well as the faint abrasion ring.

Contact range gunshot wound, gross

• An abrasion ring, formed when the force of the gases entering below the skin blow the skin surface back against the muzzle of the gun, is seen here in this contact range gunshot wound to the right temple.

Contact range gunshot wound, gross

• The abrasion ring, and a very clear muzzle imprint, are seen in this contact range gunshot wound

Contact range gunshot wound, gross

• This is a contact range gunshot entrance wound with grey-black discoloration from the burned powder

Range of fire, gunshot to skull, diagram

• The upper diagram illustrates the basic differences between the skin appearance of a contact, close (intermediate), and distant (indeterminant) range gunshot wound. The appearance of the wounding characteristics in the skull is shown in the lower diagram in which there is bevelling of the skull outward away from the direction of origin of the bullet.

Skull, contact range gunshot wound, gross

• The surface of the skull demonstrates the heavy soot in this contact range entrance wound, as well as radiating fracture lines. The direction of fire was thus toward the back of this picture.

Gunshot entrance wound with GSR, microscopic

• Histological examination of the entrance wound site on the skin demonstrates black gunshot residue and coagulative necrosis.

Intermediate range gunshot wound, gross

• This is an intermediate range gunshot entrance wound in which there is powder "tattooing" around the entrance site.

Intermediate range gunshot wound, gross

• Powder tattooing is seen in this intermediate range gunshot wound. The actual entrance site is somewhat irregular, because the bullet can tumble in flight.

Entrance-exit wound in close proximity from low angle of bullet entrance, gross • Displayed here is an

entrance at the left and an exit at the right. This particular bullet struck at an angle to produce the ovoid entrance. Exit wounds vary considerably in size and shape because the bullet can be deformed in its transit through the body. There may be no exit wound at all if the bullet's energy is absorbed by the tissues. Some bullets (such a a "hollowpoint") are designed to deform so that all their energy will be converted to tissue damage and not exit

Exit gunshot wound, gross

• Here is a slit-like exit wound. Note that there is no powder or soot visible.

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