A gunshot wound is a complex injury resulting from a projectile, typically a bullet, striking the body. The appearance of these wounds can vary significantly, influenced by numerous factors. Understanding their general characteristics is important for recognizing the severity of such injuries.
Entry Wound Characteristics
The appearance of a gunshot entry wound is influenced primarily by the distance between the firearm’s muzzle and the skin at the moment of discharge. Most entry wounds feature an abrasion collar, a rim of scraped skin formed by friction as the bullet penetrates. This collar may vary in width depending on the angle of impact.
When a firearm is in direct contact with the skin, it creates a contact wound. These wounds often show an imprint of the gun’s barrel. Gases released from the barrel can expand beneath the skin, causing stellate (star-shaped) tearing, especially over bony areas. Soot and gunpowder residue are typically present within and around the wound, sometimes with a “cherry red” discoloration from carbon monoxide absorption.
Close-range wounds occur when the muzzle is near, but not touching, the skin. These wounds are identifiable by soot around the wound and tattooing or stippling. Tattooing consists of unburnt or partially burnt gunpowder particles embedded in the skin, appearing as small abrasions. Soot may obscure the abrasion collar in these wounds.
Intermediate-range wounds are characterized by stippling, but without soot or singeing. The density and spread of stippling depend on the distance and the firearm. The pattern varies based on factors like barrel length and gunpowder amount.
Distant wounds occur when only the bullet impacts the skin. These wounds typically present as a clean, circular or oval hole with a prominent abrasion collar. They lack soot or stippling, as these residues dissipate before reaching the target.
Exit Wound Characteristics
Gunshot exit wounds generally appear more irregular and larger than entry wounds. Unlike entry wounds, they typically lack an abrasion collar, soot, or stippling. The bullet’s behavior as it exits, such as tumbling or fragmenting, often causes the tissue to be pushed outwards, resulting in a more torn or lacerated appearance.
The shape of an exit wound can vary greatly, ranging from stellate (star-shaped) or slit-like to crescent, circular, or completely irregular. Variability depends on factors like the bullet’s energy, stability (tumbling or deforming), and whether it strikes bone before exiting. If the bullet fragments or deforms significantly, it can create a much larger and more destructive exit defect.
Exit wounds may be larger than their corresponding entry wounds, particularly if the projectile expands, fragments, or encounters bone. However, size alone does not definitively distinguish an exit wound from an entry wound. The distinguishing feature remains the absence of the abrasion collar and other components of initial muzzle discharge.
Factors Influencing Wound Appearance
Several variables significantly influence a gunshot wound’s visual presentation. Projectile type plays a considerable role; for instance, a full metal jacket (FMJ) bullet often creates a cleaner, more defined wound than a hollow-point, which expands on impact, causing greater tissue disruption. Bullet fragmentation, whether by design or impact, can also lead to multiple smaller wounds or a larger, irregular defect.
Ammunition velocity and energy directly impact tissue damage. Higher-energy projectiles transfer more kinetic energy to the body, leading to more extensive disruption and larger temporary cavities. This increased energy can result in more severe internal trauma and a more significant external wound appearance.
The specific body part struck alters the wound’s appearance. Areas with varying skin elasticity, underlying bone, or different densities of muscle and organs react differently to projectile impact. For example, wounds over bone may appear more irregular due to the bullet’s interaction with the rigid structure, potentially causing bone fragmentation to act as secondary projectiles.
The angle at which the bullet enters or exits the body can create elongated or oval defects rather than perfectly circular ones. An angled shot can also produce an asymmetric abrasion collar, with a “comet tail” appearing on one side.
Clothing can affect the wound by wiping away residues like soot, altering the wound margin, or transferring fabric debris into the wound. If a bullet passes through an intermediate object (e.g., glass or a car door) before striking, it can deform or fragment, leading to an atypical wound appearance.
Understanding Internal Trauma
Though not externally visible, the internal appearance of a gunshot wound is important for understanding the full scope of the injury. The projectile creates a wound track, the path it takes through tissues. Along this track, visible damage includes bruising, tearing, and hemorrhage, as tissues are crushed and lacerated by the bullet’s passage.
Kinetic energy transfer from the bullet to tissues creates cavitation. Permanent cavitation is the actual hole left by the bullet, the volume of tissue destroyed along its path. The size of this permanent cavity is influenced by the bullet’s caliber and its deformation or fragmentation within the body.
A temporary cavity forms as tissues are stretched and displaced radially away from the bullet’s path. This temporary cavity can be significantly larger than the bullet’s diameter, especially with high-velocity projectiles. This stretching and compression can cause significant damage to tissues even some distance from the direct bullet path, leading to lacerations and ruptures of organs.
Internal trauma largely involves damage to organs and bones. Organs may exhibit lacerations, perforations, and extensive bruising, while bones can be shattered or fractured with cone-shaped defects. Fragmentation of both the bullet and bone can create numerous secondary projectiles, causing additional, widespread damage. The internal injury is frequently far more extensive than what is observable on the surface.