An extracranial carotid artery aneurysm is a bulge in the wall of one of your carotid arteries – the two main blood vessels on either side of your neck that carry oxygen-rich blood to your brain.
The bulge develops because the artery wall is weak in that spot. If one develops in the part of the artery inside your brain rather than in your neck, it’s called an intracranial carotid artery aneurysm.
Though extracranial carotid artery aneurysms seldom rupture, blood clots can form in them. If a clot breaks loose, it can block blood flow to your brain.
You’re more likely to develop an extracranial carotid artery aneurysm as you age, if you smoke or if you have:
- A connective tissue disorder
- A family history of aneurysms
- High blood pressure