Teaching Case

This pertains to 49-year-old male referred for bilateral carotid angiography because of a transient ischemic attack.

A 49-year-old male was referred for bilateral carotid angiography because of a transient ischemic attack. Digital subtraction angiography of the aortic arch showed the left common carotid artery originating from the proximal brachiocephalic trunk.

The aortic arch usually gives rise to three major branches: the brachiocephalic trunk (also known as the innominate artery), the left common carotid artery and the left subclavian artery. Many normal variations occur from this aortic arch branching pattern. The most frequently seen normal variation is a common origin of the brachiocephalic trunk and the left common carotid artery (also known as the bovine configuration). This has been reported in 1%–27% of the cases. In 7% of the cases, the left common carotid artery originates from the proximal brachiocephalic trunk as is observed in our case. In 1%–2% of the cases, the left common carotid artery and the left subclavian artery share a common origin and form a left-sided brachiocephalic trunk. The origin of the left vertebral artery directly from the arch is an uncommon variant and is seen in 0.5% of the cases. The right common carotid and right subclavian arteries may arise separately from the aortic arch in rare cases.