Most common cause of sub arachnoid hemorrhage is -

Ans. is 'b' i.e., Post traumatic Subarachnoid hemorrhage* Although aneurysms are the most common cause of spontaneous subarachnoid haemorrhage, trauma is by far the commonest cause of subarachnoid haemorrhage overall.* In rare cases, a spontaneous aneurysmal haemorrhage immediately precedes a head injury.* Traumatic subarachnoid haemorrhage is managed conservatively."Excluding head trauma, most common cause of subarachnoid hemorrhage is rupture of a saccular (Berry) aneurysm--------- Harrison