Which injury is characterized by an object penetrating the skull?

An open head injury is defined by the penetration of the skull due to an external object. This type of injury results in a breach of the protective barrier that the skull provides for the brain and often leads to direct exposure of brain tissue to the external environment. This can result in significant injury to the brain, potential infection, and other serious complications. The key feature distinguishing an open head injury is that the skin and soft tissues are torn, allowing for direct injury and access to the cranial cavity.

Closed head injuries, by contrast, occur without any puncture or break in the skull, meaning the protective layers remain intact, even though the brain can still sustain damage. Contusions and concussions are types of brain injuries that can occur after a head impact, but they do not involve penetration through the skull. A contusion refers to bruising of the brain tissue itself, while a concussion is a mild form of traumatic brain injury characterized by temporary loss of function, usually without structural damage.