Most homicide victims with isolated extremity injuries face a high risk of fatal vascular damage, emphasizing the need for bystander intervention training.

• Among 5,765 homicide autopsies, 84% had gunshot wounds; extremity injuries occurred in 47% of these cases.
• Isolated gunshot extremity wounds were linked to a 10-fold increase in major vascular injuries compared to nonisolated wounds (33% vs 5%).

Surgeons should prioritize training on hemorrhage control for isolated extremity injuries, especially in gunshot cases.

• For stab wound victims, major vascular injuries in isolated cases were less common (59% vs 9.5% in nonisolated).