Wound ballistics of gunshot injuries

Abstract

Understanding the mechanism of tissue damage by handgun and rifle ammunition involves a certain level of familiarity with the ballistic behaviour of bullets in soft targets. The damage produced may be limited to tissue disruption along the path of the penetrating projectile, which is the type of injury seen with non-deforming handgun bullets and under favourable conditions with military rifle bullets, or extended to affect the tissues surrounding the wound track. The latter pattern of injury involves significantly higher amounts of energy spent in the form of tissue displacement after the passage of the bullet, in addition to the energy normally required for simple tissue penetration. Bullet tumbling along longer wound tracks is the main mechanism of such high-energy trauma by non-deforming rifle bullets. However, when bullet construction allows deformation upon impact, the resultant injury is directly proportional to the impact velocity of the projectile. The momentum imparted to the tissue by the penetrating projectile results in a highly dynamic phenomenon of radial displacement of tissue in its wake causing the formation of a temporary cavity. Depending on the tissue tolerance to the associated tensile strain, extensive soft tissue damage may be encountered. Devitalized tissue may not be obvious during initial exploration, thus necessitating an expectant policy involving wound revision over a period of days.