From which arteries does the brain receive collateral blood flow during carotid occlusion?

The brain can receive collateral blood flow from both the carotid and vertebral arteries during carotid occlusion. This is an important aspect of cerebral circulation and is crucial for maintaining brain perfusion when the primary blood flow route is compromised.

The carotid arteries supply the anterior circulation of the brain, while the vertebral arteries contribute to the posterior circulation. When there is an occlusion in the carotid arteries, the brain may not receive sufficient blood supply from this route alone. However, it can utilize collateral pathways involving both the carotid and vertebral systems to ensure that adequate blood flow reaches critical areas of the brain.

In particular, the vertebral arteries can provide collateral flow to the brainstem and cerebellum, and through the basilar artery, they can also partake in supplying the anterior circulation via the Circle of Willis, where branches from the carotid arteries connect with the vertebral artery system. This dual supply enhances the brain's resilience to ischemic events, highlighting the significance of both arterial systems in maintaining cerebral blood flow integrity.