The most frequent cause of clinically significant subarachnoid hemorrhage is rupture of

The most frequent cause of clinically significant subarachnoid hemorrhage is rupture of a saccular ("berry") aneurysm in a cerebral aery. Subarachnoid hemorrhage may also result from the extension of a traumatic hematoma, rupture of a hypeensive intracerebral hemorrhage into the ventricular system, vascular malformation, hematologic disturbances, and tumors.Saccular aneurysm is the most common type of an intracranial aneurysm. Other aneurysm types include atherosclerotic (fusiform; mostly of the basilar aery), mycotic, traumatic, and dissecting. These latter three, like saccular aneurysms, are most often found in the anterior circulation but differ in that they more often cause cerebral infarction rather than subarachnoid hemorrhage.Ref: Robbins and Cotran Pathologic Basis of Disease; 9th edition; Chapter 28; The Central Nervous System; Page no: 1270