Anomalous branching pattern of the aortic arch and its clinical applications.

The aortic arch gives rise to three classical branches, namely the brachiocephalic trunk, the left common carotid artery and the left subclavian artery. We report a rare variation of the left common carotid artery and the right vertebral arteries originating from the brachiocephalic trunk, and the left vertebral artery that was arising from the arch of the aorta, proximal to the origin of the left subclavian artery. Variations in the branching pattern of the arch of aorta can alter the cerebral haemodynamics that leads to cerebral abnormalities. Knowledge of the variations in the classical branches of the arch of aorta is important in the diagnosis of intracranial aneurysm after subarachnoid haemorrhage.