The posterior cerebral artery (PCA) is one of a pair of

cerebral arteries The cerebral arteries describe three main pairs of artery, arteries and their branches, which perfusion, perfuse the cerebrum of the brain. The three main arteries are the: * ''Anterior cerebral artery'' (ACA), which supplies blood to the medial ...

that supply oxygenated

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is com ...

to the

occipital lobe The occipital lobe is one of the four Lobes of the brain, major lobes of the cerebral cortex in the brain of mammals. The name derives from its position at the back of the head, from the Latin , 'behind', and , 'head'. The occipital lobe is the ...

, as well as the medial and inferior aspects of the

temporal lobe The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. The temporal lobe is involved in pr ...

of the

human brain The human brain is the central organ (anatomy), organ of the nervous system, and with the spinal cord, comprises the central nervous system. It consists of the cerebrum, the brainstem and the cerebellum. The brain controls most of the activi ...

. The two

arteries An artery () is a blood vessel in humans and most other animals that takes oxygenated blood away from the heart in the systemic circulation to one or more parts of the body. Exceptions that carry deoxygenated blood are the pulmonary arteries in ...

originate from the distal end of the

basilar artery The basilar artery (U.K.: ; U.S.: ) is one of the arteries that supplies the brain with oxygen-rich blood. The two vertebral arteries and the basilar artery are known as the vertebral basilar system, which supplies blood to the posterior part o ...

, where it bifurcates into the left and right posterior cerebral arteries. These anastomose with the middle cerebral arteries and

internal carotid arteries The internal carotid artery is an artery in the neck which supplies the anterior and middle cerebral circulation. In human anatomy, the internal and external carotid arise from the common carotid artery, where it bifurcates at cervical verteb ...

via the posterior communicating arteries.

Structure

The posterior cerebral artery is subdivided into 4 segments: P1: pre-communicating segment * Originated at the termination of the basilar artery * May give rise to the artery of Percheron if present P2: post-communicating segment * From the PCOM around the midbrain * Terminates as it enters the quadrigeminal ganglion * Gives rise to the choroidal branches (medial and lateral posterior choroidal arteries) P3: quadrigeminal segment * Courses posteromedially through the quadrigeminal cistern * Terminates as it enters the sulk of the occipital lobe P4: cortical segment * Within the sulci of the occipital lobe The branches of the posterior cerebral artery are divided into two sets, ganglionic and cortical.

Central branches

The following are central branches of the PCA, also known as perforating branches: *''Thalamoperforating and thalamogeniculate'' or ''postero-medial ganglionic branches'': a group of small arteries which arise at the commencement of the posterior cerebral artery: these, with similar branches from the

posterior communicating In human anatomy, the left and right posterior communicating arteries are small arteries at the base of the brain that form part of the circle of Willis. Anteriorly, it unites with the internal carotid artery (ICA) (prior to the terminal bifurcat ...

, pierce the posterior perforated substance, and supply the medial surfaces of the thalami and the walls of the

third ventricle The third ventricle is one of the four connected cerebral ventricles of the ventricular system within the mammalian brain. It is a slit-like cavity formed in the diencephalon between the two thalami, in the midline between the right and lef ...

. * ''Peduncular perforating'' or ''postero-lateral ganglionic branches'': small arteries which arise from the posterior cerebral artery after it has turned around the

cerebral peduncle The cerebral peduncles (In Latin, ''ped-'' means 'foot'.) are the two stalks that attach the cerebrum to the brainstem. They are structures at the front of the midbrain which arise from the ventral pons and contain the large ascending (sensor ...

; they supply a considerable portion of the thalamus. Circle of Willis 4

Posterior (choroidal) branches

The posterior choroidal branches of the posterior cerebral artery are sometimes referred to as a single posterior choroidal artery. *''Medial posterior choroidal branches'': run forward beneath the

splenium The corpus callosum (Latin for "tough body"), also callosal commissure, is a wide, thick nerve tract, consisting of a flat bundle of commissural fibers, beneath the cerebral cortex in the brain. The corpus callosum is only found in placental m ...

of the

corpus callosum The corpus callosum (Latin for "tough body"), also callosal commissure, is a wide, thick nerve tract, consisting of a flat bundle of commissural fibers, beneath the cerebral cortex in the brain. The corpus callosum is only found in placental ...

, and supply the

tela choroidea of the third ventricle The tela choroidea (or tela chorioidea) is a region of meningeal pia mater that adheres to the underlying ependyma, and gives rise to the choroid plexus in each of the brain’s four ventricles. ''Tela'' is Latin for ''woven'' and is used to desc ...

and the

choroid plexus The choroid plexus, or plica choroidea, is a plexus of cells that arises from the tela choroidea in each of the ventricles of the brain. Regions of the choroid plexus produce and secrete most of the cerebrospinal fluid (CSF) of the central ...

. *''Lateral posterior choroidal branches'': small branches to the cerebral peduncle, fornix, thalamus, caudate nucleus, and choroid plexus of the lateral ventricle.

Cortical branches

The cortical branches are: *''Anterior temporal'', distributed to the

uncus The uncus is an anterior extremity of the parahippocampal gyrus. It is separated from the apex of the temporal lobe by a sulcus called the rhinal sulcus. Although superficially continuous with the hippocampal gyrus, the uncus forms morphol ...

and the anterior part of the

fusiform gyrus The fusiform gyrus, also known as the ''lateral occipitotemporal gyrus'','' ''is part of the temporal lobe and occipital lobe in Brodmann area 37. The fusiform gyrus is located between the lingual gyrus and parahippocampal gyrus above, and ...

*''Posterior temporal'', to the fusiform and the inferior temporal gyri *''Lateral occipital'', which branches into the ''anterior'', ''middle'' and ''posterior inferior temporal arteries'' *''Medial occipital'', which branches into the: **''

Calcarine sulcus The calcarine sulcus (or calcarine fissure) is an anatomical landmark located at the caudal end of the medial surface of the brain of humans and other primates. Its name comes from the Latin "calcar" meaning "spur". It is very deep, and known as ...

'', to the

cuneus The cuneus (; : cunei) is a smaller lobe in the occipital lobe of the brain. The cuneus is bounded anteriorly by the parieto-occipital sulcus and Inferior (anatomy), inferiorly by the calcarine sulcus. Function The cuneus (Brodmann area 17) r ...

and

lingual gyrus The lingual gyrus, also known as the ''medial'' occipitotemporal gyrus, is a brain structure that is linked to processing vision, especially related to letters. It is thought to also play a role in analysis of logical conditions (i.e., logical or ...

and the back part of the convex surface of the

**''

Parieto-occipital sulcus In neuroanatomy, the parieto-occipital sulcus (also called the parieto-occipital fissure) is a deep sulcus in the cerebral cortex that marks the boundary between the cuneus and precuneus, and also between the parietal and occipital lobes. Only ...

'', to the

and the

precuneus In neuroanatomy, the precuneus is the portion of the superior parietal lobule on the medial surface of each brain hemisphere. It is located in front of the cuneus (the upper portion of the occipital lobe). The precuneus is bounded in front b ...

*''Splenial'', or the posterior pericallosal branch, sometimes

anastomoses An anastomosis (, : anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf#Veins, leaf veins, or streams. Such a connection may be ...

with the anterior cerebral artery (ACA), and may not be present if the ACA wraps around the corpus callosum

Development

The

prenatal development Prenatal development () involves the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal de ...

of the posterior cerebral arteries in the

fetus A fetus or foetus (; : fetuses, foetuses, rarely feti or foeti) is the unborn offspring of a viviparous animal that develops from an embryo. Following the embryonic development, embryonic stage, the fetal stage of development takes place. Pren ...

comes relatively late and arises from the fusion of several embryonic vessels near the caudal ends of the posterior communicating arteries supplying the

mesencephalon The midbrain or mesencephalon is the uppermost portion of the brainstem connecting the diencephalon and cerebrum with the pons. It consists of the cerebral peduncles, tegmentum, and tectum. It is functionally associated with vision, hearing, mo ...

and

diencephalon In the human brain, the diencephalon (or interbrain) is a division of the forebrain (embryonic ''prosencephalon''). It is situated between the telencephalon and the midbrain (embryonic ''mesencephalon''). The diencephalon has also been known as t ...

. The PCA thus begins as a continuation of the PCommA in the fetus with only 10–30% of fetuses showing a prominent basilar origin. The fetal carotid origin of the PCA usually regresses as the vertebral and basilar arteries develop with the posterior communicating artery reducing in size. In most adults, the PCA sources from the anterior portion of the basilar artery. About 19% of adults retain PCommA dominance of the PCA, with 72% having dominant basilar origin, and the rest having either equal prominence between PCommA and basilar artery, or a single exclusive source.

Clinical significance

Stroke

*Contralateral loss of pain and temperature sensations. *Visual field defects (contralateral

hemianopsia Hemianopsia, or hemianopia, is a loss of vision or blindness ( anopsia) in half the visual field, usually on one side of the vertical midline. The most common causes of this damage are stroke, brain tumor, and trauma. This article deals only wi ...

with macular sparing). *

Prosopagnosia Prosopagnosia, also known as face blindness, (" illChoisser had even begun tpopularizea name for the condition: face blindness.") is a cognitive disorder of face perception in which the ability to recognize familiar faces, including one's own f ...

with bilateral obstruction of the lingual and fusiform gyri. *Superior Alternating Syndrome (

Weber's syndrome Weber's syndrome, also known as midbrain stroke syndrome or superior alternating hemiplegia, is a form of stroke that affects the medial portion of the midbrain. It involves oculomotor fascicles in the interpeduncular cisterns and cerebral peduncl ...

) *Ipsilateral deficits of

oculomotor nerve The oculomotor nerve, also known as the third cranial nerve, cranial nerve III, or simply CN III, is a cranial nerve that enters the orbit through the superior orbital fissure and innervates extraocular muscles that enable most movements o ...

. *Contralateral deficits of

facial nerve The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of ta ...

(only lower face, upper face receives bilateral input),

vagus nerve The vagus nerve, also known as the tenth cranial nerve (CN X), plays a crucial role in the autonomic nervous system, which is responsible for regulating involuntary functions within the human body. This nerve carries both sensory and motor fibe ...

and

hypoglossal nerve The hypoglossal nerve, also known as the twelfth cranial nerve, cranial nerve XII, or simply CN XII, is a cranial nerve that innervates all the extrinsic and intrinsic muscles of the tongue except for the palatoglossus, which is innervated b ...

. *

Horner's Syndrome Horner's syndrome, also known as oculosympathetic paresis, is a combination of symptoms that arises when a group of nerves known as the sympathetic trunk is damaged. The signs and symptoms occur on the same side (ipsilateral) as it is a lesion ...

Signs and symptoms: ''Structures involved''

Peripheral territory (cortical branches)

* Homonymous

(often upper quadrantic): ''Calcarine cortex or optic radiation nearby''. * Bilateral homonymous hemianopsia, cortical blindness, awareness or denial of blindness; tactile naming, achromatopia (color blindness), failure to see to-and-fro movements, inability to perceive objects not centrally located, apraxia of ocular movements, inability to count or enumerate objects, tendency to run into things that the patient sees and tries to avoid: ''Bilateral occipital lobe with possibly the parietal lobe involved''. * Verbal dyslexia without agraphia, color anomia: ''Dominant calcarine lesion and posterior part of corpus callosum''. * Memory defect: ''Hippocampal lesion bilaterally or on the dominant side only''. * Topographic disorientation and prosopagnosia: ''Usually with lesions of nondominant, calcarine, and lingual gyrus''. * Simultanagnosia, hemivisual neglect: ''Dominant visual cortex, contralateral hemisphere''. * Unformed visual hallucinations, peduncular hallucinosis, metamorphopsia, teleopsia, illusory visual spread, palinopsia, distortion of outlines, central photophobia: ''Calcarine cortex''. * Complex hallucinations: ''Usually nondominant hemisphere''.

Central territory (ganglionic branches)

* Thalamic syndrome: sensory loss (all modalities), spontaneous pain and dysesthesias, choreoathetosis, intention tremor, spasms of hand, mild hemiparesis, contralateral hemianaethesia: ''Posteroventral nucleus of thalamus; involvement of the adjacent subthalamus body or its afferent tracts''. * Thalamoperforate syndrome: crossed cerebellar ataxia with ipsilateral third nerve palsy (Claude's syndrome): ''Dentatothalamic tract and issuing third nerve''. * Weber's syndrome: third nerve palsy and contralateral hemiplegia: ''Third nerve and cerebral peduncle''. * Contralateral hemiplegia: ''Cerebral peduncle''. * Paralysis or paresis of vertical eye movement, skew deviation, sluggish pupillary responses to light, slight miosis and ptosis (retraction nystagmus and "tucking" of the eyelids may be associated): ''Supranuclear fibers to third nerve, interstitial nucleus of Cajal, nucleus of Darkschewitsch, and posterior commissure''. * Contralateral rhythmic, ataxic action tremor; rhythmic postural or "holding" tremor (rubral tremor): ''Dentatothalamic tract''.

Additional images

File:Mra1.jpg, Arteriogram of the arterial supply. File:Gray518.png, Medial surface of cerebral hemisphere, showing areas supplied by cerebral arteries. Areas supplied by the posterior cerebral artery shown in yellow. File:Arteries_beneath_brain_Gray_closer.jpg, The arteries of the base of the brain. Posterior cerebral artery labeled near center. The temporal pole of the

cerebrum The cerebrum (: cerebra), telencephalon or endbrain is the largest part of the brain, containing the cerebral cortex (of the two cerebral hemispheres) as well as several subcortical structures, including the hippocampus, basal ganglia, and olfac ...

and a portion of the

cerebellar The cerebellum (: cerebella or cerebellums; Latin for 'little brain') is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as it or e ...

hemisphere have been removed on the right side. Inferior aspect (viewed from below).

References

External links

* – Posterior cerebral artery stroke * * *
Overview

Angiography
at

State University of New York Upstate Medical University The State University of New York Upstate Medical University (SUNY Upstate) is a public medical school in Syracuse, New York. Founded in 1834, Upstate is the 15th oldest medical school in the United States and is the only medical school in Centr ...

Diagram

{{Authority control Arteries of the head and neck