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.University of Vermont College of Medicine. "Neuropathology: Trauma to the CNS." Accessed through web archive on August 8, 2007. 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.
