The role of vertebral angiography in the investigation of third nerve palsy.

The association between intracranial aneurysm and third nerve palsy in a series of fifty patients presenting to this unit over a six year period has been studied. All aneurysms causing a third nerve palsy were found to be in the anterior circulation and all were adequately demonstrated by carotid angiography alone. None of the thirty cases of posterior circulation aneurysm was associated with a third nerve palsy. Vertebral angiography carries a higher risk of serious complications than carotid angiography. We feel that the added risk of vertebral angiography is not justified for the investigation of an isolated third nerve palsy.