Which injury occurs when the skull is fractured or when it is pierced by a penetrating object?

• A. Closed traumatic brain injury
• B. Open traumatic brain injury
• C. Diffuse axonal injury
• D. Concussion

Answer: (B)

Open traumatic brain injury is defined by a skull fracture or a penetrating object breaching the skull and dura, creating a direct outside-to-brain pathway. This distinguishes it from injuries where the skull remains intact (closed TBI). A penetrating wound or fracture directly involves the skull and exposes brain tissue, often with a higher risk of infection and focal damage at the entry point. The other options describe injuries without a skull breach: concussion is a mild, transient disturbance of brain function; diffuse axonal injury is widespread damage to white matter from rapid acceleration-deceleration, not specifically tied to a skull fracture or penetration.