<prompt> Most common cause of cerebrovascular accident is :EmbolismAerial thrombosisVenous thrombosisHaemorrhage  <response>: Answer is A Embolism: The most common cause of cerebrovascular accidents is embolism. Harrisons 16th has not classified ischaemic strokes into thrombotic and embolic events but into Atherosclerosis 4, cardioembolic 17, others 64. Neveheless even others 64 include most commonly embolic events other than those of cardiac origin such as aery to aery embolic strokes etc. and hence the answer stays the same. 