What is Penetrating head injury?

A penetrating head injury, or open head injury, is a head injury in which the dura mater, the outer layer of the meninges, is breached. Penetrating injury can be caused by high-velocity projectiles or objects of lower velocity such as knives, or bone fragments from a skull fracture that are driven into the brain. Head injuries caused by penetrating trauma are serious medical emergencies and may cause permanent disability or death.

A penetrating head injury involves "a wound in which an object breaches the cranium but does not exit it." In contrast, a perforating head injury is a wound in which the object passes through the head and leaves an exit wound.