Vertebral artery variant: external carotid artery origin

Case contributed by Dr Brian Gilcrease-Garcia


Recurrent amaurosis fugax.

Patient Data

Age: 60 years
Gender: Female

CT angiography performed in order to evaluate for carotid artery atherosclerosis shows moderate-to-severe atherosclerotic narrowing of both carotid bulbs with evidence of ulceration. There is a second short segment severe stenosis of the right cervical segment internal carotid artery.

Incidentally, the left vertebral artery originates directly from the proximal external carotid artery. A diminutive right vertebral artery originates from the right brachiocephalic artery.

Case Discussion

Minor variations in the greater arterial anatomy of the neck are commonplace. This case demonstrates a rare congenital anatomic variant, whereby a truncated and prominent left vertebral artery originates from the proximal external carotid artery. Consequently, there is absence of the left pre-/foraminal segment vertebral artery.

Although this particular configuration is quite unusual, it is important to maintain an awareness of such anatomic variations, as they may be mistaken for vertebral artery thrombosis in the acute setting.
Case-in-point: this was originally interpreted as "non-opacification of the left vertebral artery"

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