A closed head injury is a type of traumatic brain injury (TBI) where the brain is damaged without any penetration of the skull. Unlike an open head injury, where there is a visible wound or fracture to the skull, a closed head injury occurs when the brain is subjected to a sudden impact or force, but the skull remains intact. These injuries are often the result of blunt force trauma, such as from a fall, car accident, sports injury, or physical assault.