Figure 2.

Basilar artery segments: proximal from the vertebrobasilar junction to the origin of the AICA, mid from the AICA to the origin of the SCA, and distal after the origin of the SCA. AICA: anteroinferior cerebellar artery; ASA: anterior spinal artery; PCA: posterior cerebral artery; PCOM: posterior communicating artery; PICA: posteroinferior cerebellar artery; SCA: superior cerebellar artery; VA: vertebral artery (figure adapted Samaniego EA, Shaban A, Ortega-Gutierrez S et al. Stroke mechanisms and outcomes of isolated symptomatic basilar artery stenosis. Stroke Vasc Neurol. 2019; 4:189–197.)