Posterior Cerebral Circulation

The posterior cerebral circulation is a major component of the bleed flow to the brain that supplies oxygenated blood to the posterior midbrain and superior cerebellum. The major arterial supply of the posterior cerebral circulation is the posterior communicating artery (PCoA), which is a branch of the internal carotid artery. Additionally, the pericallosal branch of the posterior cerebral artery (PCA) supplies the midbrain, thalamus, striatum, occipital lobe, and superior cerebellum. The PCA usually emerges from the posterior cerebral arterial circle, which is also known as the circle of Willis. The PCA is a paired artery that branches from the basilar artery, which is collaterally connected to the vertebral artery and both anterior cerebral arteries. The PCA has many branches and supplies blood to the thalamus, midbrain, inferior and superior colliculi, medial, lateral, and inferior temporal poles, lateral geniculate nuclei, and uncus. The thalamus and inferior colliculus are major relay and integration regions that are important in sensory, motor, visual, and other complex functions. The superior colliculus receives afferents from the retinal, vestibular, and auditory nucleus regions and is responsible for eye movement responses. The posterior cerebral artery is extremely important for normal brain function as it supplies blood to the medial, lateral, and inferior temporal poles, lateral geniculate nucleus, uncus, thalamus, inferior colliculus, and midbrain, which are critical for vision, speech, motor control, and consciousness. Additionally, the PCA has branches connecting to the anterior cerebral artery and vertebral artery via the posterior communicating artery, which creates a collateral network of blood flow to these regions in case one artery becomes blocked. This provides increased protection against ischemia that can result from blockages in the major cerebral vessels.