Basilar artery
Vertebral artery segment V4 (intradural): from the dura to their confluence to form the basilar artery.
Formed by the junction of the 2 vertebral artery.
The two vertebral arteries and the basilar artery are sometimes together called the vertebrobasilar system, which supplies blood to the posterior part of the circle of Willis and anastomoses with blood supply to the anterior part of the circle of Willis from the internal carotid arteries.
It ascends in the central gutter (sulcus basilaris) inferior to the pons and divides into the posterior cerebral arteries and the superior cerebellar artery just inferior to the pituitary stalk.
The basilar arterial bifurcation is the most common site for aneurysms arising from the posterior circulation.
V4 vertebral artery segment pierces the dura (location somewhat variable) and immediately enters the subarachnoid space. Joins the contralateral VA at the vertebral confluence located at the lower pontine border to form the basilar artery (BA).
Branches
Segments
Territory
The basilar artery territory refers to the area of the brain supplied by the basilar artery and its branches. This territory is critical for many essential functions as it provides blood flow to the brainstem, cerebellum, occipital lobes, and parts of the thalamus.
Functional Areas in the Basilar Artery Territory
1. Brainstem:
- Midbrain, pons, and medulla oblongata.
- Contains critical nuclei and pathways for autonomic and motor functions.
2. Cerebellum:
- Coordination of voluntary movements and balance.
3. Thalamus:
- Relays sensory and motor signals.
4. Occipital lobes:
- Responsible for visual processing.
5. Inner ear structures (via AICA):
- Critical for hearing and balance.
Clinical Significance
Understanding the basilar artery territory is vital for diagnosing and treating posterior circulation disorders effectively.