Cerebral Blood Vessel Anatomy

Overview

This lecture covers the angiographic anatomy of cerebral blood vessels, focusing on the internal carotid artery (ICA), vertebral-basilar system, and aneurysm-related clinical implications.

Angiographic Anatomy: Anterior Circulation

• The internal carotid artery (ICA) supplies the anterior cerebral circulation.
• AP (anteroposterior) and lateral angiographic views visualize ICA, middle cerebral artery (MCA), and anterior cerebral artery (ACA).
• The bifurcation of the ICA is best seen in the AP view.

Angiographic Anatomy: Posterior Circulation

• The vertebral artery supplies the posterior cerebral circulation.
• Major branches: posterior inferior cerebellar artery (PICA), anterior spinal artery (ASA), basilar artery, anterior inferior cerebellar artery (AICA), superior cerebellar artery (SCA), posterior cerebral artery (PCA).
• Both coronal and lateral views highlight these branches and their origins.

Internal Carotid Artery (ICA) Segments - Bouthillier Classification

• ICA segments, from proximal to distal: petrous, cavernous, clinoid (between dural rings), ophthalmic, and communicating.
• Petrous and cavernous segments are extradural (inside the skull, but outside the dura mater).
• Aneurysms in extradural ICA segments generally do not cause subarachnoid hemorrhage but may cause mass effect.
• The clinoid segment is situated between the dural rings and is functionally extra-dural; aneurysms here also rarely cause intracranial hemorrhage.
• The ophthalmic segment (ophthalmic artery to posterior communicating artery) can produce intradural aneurysms with subarachnoid hemorrhage risk, though most carry low rupture risk.
• The communicating segment runs from the posterior communicating artery (PCom) to the ICA terminus.

Key Terms & Definitions

• Aneurysm — abnormal bulging of a blood vessel wall; risk of rupture and hemorrhage.
• AP view (anteroposterior) — imaging viewed from front to back.
• Lateral view — imaging viewed from the side.
• Extradural — located outside the dura mater (outer brain membrane).
• Intradural — located within the dura mater.
• Subarachnoid hemorrhage — bleeding into the space between the brain and the tissues covering it.

Action Items / Next Steps

• Review labeled cerebral angiograms for vessel and segment identification.
• Study the Bouthillier classification of ICA segments for clinical relevance.
• Prepare questions on aneurysm locations and their clinical consequences.