Radiography is an essential component of firearm injury examination. Anteroposterior and lateral radiographs assist in determining the location, nature, and
path of projectiles in the body (16). Lateral radiographs are particularly helpful if there is an anterior torso entry and the bullet does not exit from the back. Reliance on only an anteroposterior radiograph leads to a mistaken assumption that a bullet is deep within the body, resulting in a time-consuming search. The posterior location of the projectile, indicated on the lateral radiograph, means that simply palpating and incising the skin on the back allows easy recovery (Fig. 12). More sophisticated radiological techniques (MRI, CT) may play a role in the assessment of firearm injuries (161).
The deposition of radiodense material (lead) from nonjacketed bullets around a contact or near-contact wound assists in distinguishing an entry from an exit wound,
useful when wounds have been obscured by blood, thick hair, skin pigmentation, decomposition, medical alteration, and insect or animal activity (160,162,163). The presence of lead is confirmed by scanning electron microscopy/energy-dispersive X-ray. Skull wounds owing to gunshots can have lead fragments deposited on the outer table of the cranium (16). Lead fragments also indicate the path of a wound track. Lead fragments can trace the path of an intracranial ricochet (see Subheading 19.4. and ref. 16).
High-velocity ammunition fragments (e.g., from a hunting rifle) create a "snowstorm" pattern (Fig. 39). Despite the observation that metal fragments from a partly jacketed centerfire weapon are distributed as a cone with its apex oriented toward the entry, one study showed that predicting the direction of travel, based only on lead "snowstorm" seen on a radiograph, was difficult (162).
Shotgun wadding is not usually radiopaque. An exception occurs when lead is deposited on fiber wads (16,124). Dispersal of pellets ("billiard ball effect") in the body is not a sign of a distant shotgun wound and is seen in contact wounds (Fig. 17; refs. 16 and 124). Pellets can deform within the body (164).
Radiographs are also used to document other foreign bodies and injuries (56). Radiographs demonstrate unique features of certain types of projectile injuries (119). Tandem projectiles (e.g., .22-caliber bullet and barrel-cleaning brush from a rifle) have been observed (165). In nailgun suicides, a straight steel nail is found in a self-inflicted wound as opposed to a bent nail in a bystander or user accidentally injured by a ricochet (85,166-168). A straight nail can be seen in a bystander when the nail has over-penetrated a wall or was fired in midair.
Radiographs must be done in any case where there is an apparent exit. That exit can be created by a partly fragmented bullet or a piece of bone ( 16). If there is a jacket and core separation of a partly jacketed bullet in the body, radiographs help in the recovery of the jacket, which shows rifling striations (see Heading 21; Fig. 40; and ref. 16). Even when there is considerable skull destruction from shotgun pellets, a radiograph confirms the presence of at least a few residual pellets (16). A radiograph can locate small residual fragments of a projectile in a through-and-through gunshot wound. These fragments can be analyzed and compared with ammunition that may have been used (16). If a projectile is not evident in the radiograph despite the lack of a skin exit, then possibilities include an ignored or missed exit, a nonradiopaque projectile (e.g., plastic bullet), projectile embolization (usually shotgun pellets, small-caliber bullets) and discharge of a blank cartridge (16,73,92,93,169,170).
If the bullet and its fragments are not found after the brain is removed, the brain must be X-rayed to confirm that the bullet is still present. Bullets can migrate within the cranium (171,172).
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