<prompt> Most common cause of sub arachnoid hemorrhage is -Berry aneurysm rupturePost traumaticHypertensive bleedCoagulation disorder  <response>: 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 