In penetrating trauma, a permanent cavity is formed by the projectile contacting tissues. How is a temporary cavity formed?

The correct answer is the option identifying that a temporary cavity is formed by energy scrubbing off of the projectile. In the context of penetrating trauma, when a projectile, such as a bullet, travels through body tissues, it creates a significant amount of energy upon impact. This energy causes the surrounding tissues to temporarily stretch and expand, creating a temporary cavity.

As the projectile moves, it imparts kinetic energy to the surrounding tissues, causing them to move outward and create this temporary cavity. After the projectile has passed through, the tissues will return somewhat to their original state, which is why this cavity is described as temporary. This understanding of temporary and permanent cavities is crucial in trauma assessment and management, as it helps to predict potential tissue damage and impacts on neighboring structures.

The other options may relate to projectile behavior or effects, but they do not accurately describe the mechanism by which the temporary cavity is formed during penetrating trauma. The formation of a temporary cavity specifically pertains to the energy transfer from the projectile to the tissues.