POSTTRAUMATIC headaches (PTHs) can be classified as either acute or chronic,1 the latter persisting for longer than 8 weeks. The traumatic events that cause PTH include motor vehicle crashes, worker's compensation injuries, assault, surgical procedures, and simple falls or other household injuries. The principal site of injury is often the neck, lower back, or other places remote from the headache. The severity of direct trauma to the head frequently does not relate to the severity or duration of the headaches that follow.
Warner JS. Posttraumatic Headache—A Myth?. Arch Neurol. 2000;57(12):1778-1780. doi:10.1001/archneur.57.12.1778