A head injury is an injury to the brain or skull, which can be caused by a variety of events such as falls, car accidents, sports injuries, and violence. The severity of a head injury can vary greatly - from mild (such as a bump on the head) to severe (such as a traumatic brain injury). Symptoms may include pain or discomfort, confusion, memory problems, difficulty concentrating, blurred vision, dizziness, and nausea. Treatment for head injuries can range from rest and observation to surgery, depending on the severity of the injury.