In rotational injuries, which description best captures the resulting brain injury?

• A. A diffuse brain injury such as a concussion
• B. A localized skull fracture
• C. A minor superficial bruise
• D. No injury

Answer: (A)

Rotational forces produce widespread disruption in the brain because the tissue is pulled at different speeds as the head twists. This causes shear injuries along many neural pathways, leading to a diffuse pattern of damage—what we call a diffuse brain injury, typically presenting as a concussion or diffuse axonal injury. The injury isn’t confined to one spot, and symptoms can be out of proportion to any visible damage on the skull.

This is why a skull fracture or a tiny superficial bruise isn’t the best description for rotational injuries—the damage isn’t mainly to the skull or a superficial skin area, and saying there’s no injury would ignore the brain impact. In mild cases, imaging can even look normal, yet there can be significant functional impairment from the diffuse disruption.