A head injury is any trauma to the scalp, skull, or brain. The injury may be only a minor bump on the skull or a serious brain injury. A head injury can be either closed or open (penetrating). A closed head injury means you received a hard blow to the head from striking an object, but the object did not break the skull. A head injury is any trauma to the scalp, skull, or brain. The injury may be only a minor bump on the skull or a serious brain injury. A head injury can be either closed or open (penetrating). A closed head injury means you received a hard blow to the head from striking an object, but the object did not break the skull. Head injuries may be either closed or open. A closed head injury is any injury that doesn’t break your skull. An open (penetrating) head injury is one in which something breaks your scalp and skull and enters your brain.