[Three cases of infra-optic course of the anterior cerebral artery]

Three cases of rare anomalous cerebral artery originating from internal carotid at the level of ophthalmic artery to join the anterior cerebral artery were presented. Case 1. A 32-year-old woman was admitted following subarachnoid hemorrhages. Cerebral angiography disclosed the anterior communicating artery aneurysm and the anomalous vessel originating at rt. carotid siphon to join anterior cerebral artery. Case 2. A 37-year-old woman was admitted with rt. hemiparesis and aphasia. Cerebral angiography revealed the anomalous vessel originating at rt. carotid siphon to join contralateral anterior cerebral artery. Case 3. A 22-day-old male infant with enlarged head was admitted and cerebral angiography was performed. Anomalous vessel originating from internal carotid at the level of ophthalmic artery joined to the azygos anterior cerebral artery. There were only sixteen reported cases of this anomaly including our three cases. Seven aneurysms were associated in six cases, in which four were located in anterior communicating system. The fact that among the cases of this anomaly, ophthalmic artery used to not have normal stem but be fed from middle meningeal or middle cerebral artery suggested that the anomalous vessel had the common stem with ophthalmic artery at certain embryonic stage. These considerations led us to the conclusion that this anomalous vessel might originate from the remnant of anastomotic loop between primitive dorsal and ventral ophthalmic artery.