The Posterior Cerebral Artery (PCA) is a major blood vessel in the brain that supplies oxygenated blood to the posterior parts of the cerebral hemispheres. It primarily nourishes areas responsible for vision, including the occipital lobe and parts of the temporal lobe. The PCA branches off from the Basilar Artery, which is formed by the union of the two vertebral arteries. In addition to the occipital lobe, the PCA also supplies blood to the thalamus and the inferior surface of the brain. Blockages or damage to the PCA can lead to visual disturbances and other neurological deficits, highlighting its importance in maintaining proper brain function.