It is not possible to generalize whether a fall on the back of the head has a latent period, but if the fall is severe, there is usually a latent period before the situation deteriorates, so it is important not to let down your guard too soon. In case of head trauma, it is most important to be alert to the formation of intracranial hematoma, which can cause an increase in intracranial pressure and may even lead to brain herniation. In some patients who have fallen on the back of the head, there may be no obvious abnormalities in the initial head CT, but it does not mean that the head situation is relatively stable, as time goes by, delayed intracranial hemorrhage may occur, and there is a certain latency period, and 6 hours after the injury is usually the peak period of rebleeding. It is recommended to recheck the head CT 72 hours after the fall and if no abnormalities are found, intracranial hemorrhage can be ruled out. If the patient has symptoms such as headache, nausea, and impaired consciousness within 72 hours after the injury, the possibility of intracranial hemorrhage needs to be highly suspected, and the patient should immediately go to the emergency department or neurology department of the hospital to improve the examination and be hospitalized. Therefore, within 72 hours after falling and injuring the back of the head, the patient should be closely observed for symptoms or changes in condition, and if there is any abnormality, promptly seek medical attention so as not to delay the best time for treatment.