Depressed pit on the top of the head can be seen in physiologic, trauma, cranial bone loss and other causes. 1. Physiological: For example, when a newborn is born, there is a prismatic depression on the top of the head due to the gap between the skull and the cranium, so there is a depressed pit on the top of the head. Under normal circumstances, the general six months physiological enlargement, six months after the beginning of shrinkage, 12 ~ 18 months gap will appear healing. 2. Trauma: The skull is fractured due to trauma, so there is a possibility of a sunken pit on the top of the head. 3. Missing skull: for example, surgical removal of the skull, there is also the possibility of a sunken pit on the top of the head. There may be other reasons why there is a sunken pit on the top of the head, it is recommended to go to the regular hospital in time, under the guidance of the doctor to clarify the cause of the disease, the next step in the treatment.