What Are the Functions of a Right Posterior Artery?

The term "right posterior artery" generally refers to the right posterior cerebral artery (PCA). The function of this artery is to supply blood to several regions of the brain roughly toward the back and toward the bottom on the sides. These regions are known as the occipital lobe and the posteroinferior region of the temporal lobe, respectively. Smaller arteries that branch off the posterior cerebral artery also deliver blood to a part of the brainstem known as the midbrain. Without a fully functioning posterior cerebral artery, the brain experiences many types of dysfunction. This can happen, for example, when a person suffers a stroke involving the posterior cerebral artery.

Vision

• One of the functions of the PCA is to deliver blood to occipital lobe, which houses brain structure relating to sight. When the PCA no longer fulfills that function, visual problems known as scotomoa and hemianopia result. Scotoma refers to spots in the visual field where there is no vision or only poor vision. Hemianopia is a condition in which vision is absent in half the visual field of each eye. For problems with the right PCA, vision problems would affect the left side of the visual field of each eye. If both left and right PCA are affected, complete blindness can result.

Memory

• Another function of the PCA is to bring blood to the bottom regions of the temporal lobe. This region of the brain is involved in processing short-term memory and integration of memory with perception by the senses. Damage to the part of the PCA that serves this region can result in memory loss or perceptual difficulties, such as inability to recognize objects or faces. The specific type of memory loss associated with PCA damage is known as anterograde amnesia, which is the inability to retain new memories or learn new things.

Consciousness and Alertness

• A third brain region served by the PCA is the thalamus. When this part of the PCA is damaged on both left and right sides of the brain, patients can experience problems staying awake or being alert. Although most people who suffer these symptoms after PCA damage regain consciousness, they typically have permanent memory loss. If only the right PCA is damaged, the left half of the thalamus will continue to function because it receives blood from the left PCA.

Other Functions

• The PCA is also important in supporting a number of other brain structures, including the splenium and hippocampus. Damage to the PCA can result in agitated delirium, reading difficulty, difficulty with sense of smell and disorders of color perception. Movement problems or paralysis can also occur; if only the right PCA is involved, these dysfunctions will affect the left side of the body. Reading difficulty or other problems involving language are more likely with damage to the left PCA, while damage to the right PCA is more likely to bring about memory problems.