<prompt> The most common cause of subarachnoid hemorrhage is:Aeriovenous malformationCavernous angiomaAneurysmAneurysm  <response>: Answer is C Aneurysm: The most common cause of subarachnoid haemorrhage is rupture of a saccular aneurysm Saccular aneurysms are synonymous with Berry Aneurysms or Circle of Willis aneurysms and most commonly occur in the anterior circulation on the Circle of Willis. 