The posterior cerebral artery (PCA) is a critical vessel in the brain's blood supply, primarily responsible for providing oxygenated blood to the occipital lobes, the inferior part of the temporal lobes, and various deep structures including the thalamus. Occlusion or damage to the PCA can lead to significant neurological deficits, including visual disturbances, thalamic pain syndrome, and memory issues due to its role in perfusing key brain regions.