Subarachnoid hemorrhage often occurs spontaneously and due to trauma. Spontaneous subarachnoid hemorrhages are usually caused by the rupture of an aneurysm. They have relatively obvious manifestations on CT, appearing as increased columnar strip densities in areas like the suprasellar cistern, quadrigeminal cistern, cerebellar tent, falx cerebri, and lateral fissure pools, as well as strip-like high density shadows within the cerebral sulci and gyri. If the subarachnoid hemorrhage is traumatic, the CT manifestations are generally mild, potentially only showing local fuzziness of the cerebral septum. At the same time, there may also be brain contusion-laceration injuries, such as extradural hematoma, subdural hematoma, and skull fractures.