Is fragile. The back of the head is fragile because there are many important nerves and blood vessels in the back of the head, including important structures such as brain stem, cerebellum and medulla oblongata. These structures and blood vessels are easy to be damaged when they are hit by external forces, leading to intracranial hemorrhage, concussion and other problems, and may even be life-threatening. The skull tissue in the back of the head is also very weak. If an accident occurs, such as a heavy blow or a car accident, skull fracture may occur, resulting in intracranial tissue damage. Therefore, we should pay attention to protecting the back of the head in daily life and try to avoid being hit or squeezed by external forces.