Head trauma can range from a minor or major bump on the skull producing a bruise or visible enlarged area to a severe open wound, explains Medline Plus. Head trauma that results in internal injury or damage may not show any visible lacerations or legions on the head.
Head trauma can cause patients to experience scalp wounds, skull fractures or a concussion, according to Medline Plus. Nonvisible symptoms of head trauma may include sleepiness, abnormal behavior, stiff neck, severe headache and loss of consciousness. Head trauma also can cause bleeding in the brain tissue or in the layers that are connected to the brain. Any type of head trauma should be evaluated by a medical professional immediately.