What is primarily affected in a primary blast injury?

In a primary blast injury, internal organs are primarily affected due to the effects of the pressure wave generated by an explosive blast. This wave travels through the air and can cause significant damage to the body, particularly to hollow organs such as the lungs, intestines, and other organ systems. The high-pressure wave can lead to a variety of injuries, including pneumothorax (collapsed lung), abdominal hemorrhage, and concussive brain injuries. These injuries can occur even in the absence of shrapnel, fractured bones, or external wounds, which are typically associated with secondary or tertiary blast injuries.

During an explosion, the force from the blast wave does not discriminate based on external tissues but rather directly affects internal structures where pressure changes can cause trauma. Understanding the mechanism of primary blast injuries is crucial for effective assessment and management in combat medicine scenarios, as the recognition of such injuries can significantly affect treatment and outcomes.