[Orthostatic arterial hypotension and giant aneurysm of the basilar trunk]

The authors report two observations of giant aneurysm of basilar artery, where the first neurological signs were preceded or escorted by a postural hypotension. They emphasize the place of rhombencephon in the control of blood pressure and they bring together their cases with those reporting a postural hypotension revealing a lesion of medulla. They insist upon the necessity to look a peripheric and central neurological lesion in front of a postural hypotension.