Brainstem arterial groups
The brainstem vascular territories (as originally defined in the 1960s by Gillian and Lazorthes) divide into: anteromedial, anterolateral, lateral, and posterior groups.
The thin paramedian region is the:
- Anteromedial group
The remainder of the brainstem (from anterior to posterior) are the:
- Anterolateral group
- Lateral group
- Posterior group
Brainstem: Specific Vascular supply
Midbrain
Key Anatomy
- The PCAs or distal basilar artery supply the midbrain, either directly or via smaller branches.
- When basilar clot produces ischemia to the proximal PCAs, large midbrain strokes can occur and produce a so-called "top of the basilar" syndrome.
Clinical Correlation: Basilar Occlusion
Detailed Anatomy
- The anteromedial group is supplied by basilar tip and proximal PCA branches.
- From inferior to superior, these branches are the inferior and superior paramedian mesencephalic arteries and the thalamoperforate arteries.
- The anterolateral group is supplied by PCA branches: the collicular and posteromedial choroidal arteries.
- The lateral and posterior groups are also supplied by the collicular and posteromedial choroidal arteries in concert with the superior cerebellar arteries.
Pons
Key Anatomy
- Most of the pontine arterial supply comes in the form of circumferential artery branches that travel progressively farther distances to their targets.
- The posterior portion of the pons receives additional supply from the anterior inferior cerebellar artery, inferiorly, and the superior cerebellar artery, superiorly.
- The common source for these arteries is the basilar artery.
- Basilar ischemia can produce pontine basis strokes, which can cause locked-in-syndrome.
Detailed Anatomy
- The anteromedial group is supplied by the pontine paramedian arteries.
- The anterolateral group is supplied by the short pontine circumferential arteries.
- The lateral group is supplied by the long pontine circumferential arteries and the anterior inferior cerebellar arteries.
- The posterior group is supplied by the superior cerebellar arteries: note that the posterior group is found only in the upper pons — it is not present in the mid or lower pons.
Medulla
Key Anatomy
- Key medullary arterial vessels are: the anterior spinal artery and the posterior inferior cerebellar arteries.
- The common source for these arteries is the vertebral arteries.
- As a clinical corollaries:
- Ischemia to the posterior inferior cerebellar artery results in lateral medullary syndrome, called Wallenberg's syndrome.
- Ischemia to the medial medulla results in Dejerine's syndrome.
Detailed Anatomy
- The anteromedial group is supplied by the anterior spinal artery and direct vertebral artery branches.
- The anterolateral group is supplied by the anterior spinal artery and the posterior inferior cerebellar arteries.
- The lateral group is supplied by the posterior inferior cerebellar arteries.
- The posterior group is supplied by the posterior inferior cerebellar and posterior spinal arteries.