Internal carotid artery

Arteria carotis interna

CardiovascularBlood vesselsHeadLeft and right

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What it is

Rises from the carotid bifurcation without branches in the neck, enters the skull through the carotid canal of the temporal bone, bends forward through the cavernous sinus beside the pituitary (the carotid siphon) and ends by dividing into the anterior and middle cerebral arteries.

Function

Supplies most of the cerebral hemisphere on its side and, via the ophthalmic artery, the eye.

Size

~5 mm diameter at its origin (carotid bulb); ~4 mm intracranially.

Clinical note

Narrowing at its origin (carotid stenosis) is treated by endarterectomy or stenting to prevent stroke; transient blindness in one eye (amaurosis fugax) is a warning sign.