Each vessel courses superiorly along each side of the neck, merging within the skull to form the single, midline basilar artery.

[1] The vertebral arteries usually arise from the posterosuperior aspect of the central subclavian arteries on each side of the body,[2] then enter deep to the transverse process at the level of the 6th cervical vertebrae (C6),[1] or occasionally (in 7.5% of cases) at the level of C7.

[8] In 3-15% of the population, a bony bridge called the arcuate foramen covers the groove for the vertebral artery on vertebra C1.

[9] The portion of vertebral arteries located within the skull (intracranial) have diameters of 3.17 mm.

[citation needed] Chiropractic manipulation of the neck has the potential to cause a vertebral arterial dissection.

[12][13][14] The condition and health of the vertebral carotid arteries is usually evaluated using Doppler ultrasound, CT angiography or phase contrast magnetic resonance imaging (PC-MRI).