The posterior cerebral arteries (PCAs) are two major blood vessels that supply oxygenated blood to the back part of the brain, particularly the occipital lobe and the inferior part of the temporal lobe. They branch off from the basilar artery and play a crucial role in providing nutrients to areas responsible for vision and visual processing. Each PCA has several branches that further supply blood to specific regions, including the thalamus and parts of the brainstem. Proper functioning of the PCAs is essential for maintaining healthy brain activity, and any blockage or damage can lead to visual disturbances or other neurological issues.