Trigeminal artery: a review of normal and pathological features

Objects Carotid–vertebrobasilar anastomoses—the trigeminal, otic, hypoglossal, and proatlantal intersegmental arteries—serve as transitory channels between primitive internal carotid arteries and bilateral longitudinal neural arterial plexus, which is the precursor of future basilar artery, when the human embryo reaches about 4-mm length.