Anterior cerebral artery

Artery: Anterior cerebral artery
Outer surface of cerebral hemisphere, showing areas supplied by cerebral arteries. (Blue is region supplied by anterior cerebral artery.)
The arterial circle and arteries of the brain. The anterior cerebral arteries (top of figure) arise from the trifurcations of the internal carotid arteries into the anterior cerebral artery, middle cerebral artery and posterior communicating artery on each side.
Latin	arteria cerebri anterior
Gray's	subject #146 571
Supplies	cerebrum
Source	internal carotid artery
Vein	cerebral veins
MeSH	Anterior+Cerebral+Artery

The anterior cerebral artery (ACA) is one of a pair of arteries on the brain that supplies oxygenated blood to most medial portions of the frontal lobes and superior medial parietal lobes. The two anterior cerebral arteries arise from the internal carotid artery and are part of the Circle of Willis.

The left and right anterior cerebral arteries are connected by the anterior communicating artery.

Segments and branches

The ACA is classified into 5 segments with the smaller branches from the ACA "callosal" arteries (supracallosal) considered as the A4 and A5 segments:^[1]

• A1: this segment originates from the internal carotid artery and extends to the anterior communicating artery (AComm). The anteromedial central (medial lenticulostriate) arteries arise from this segment as well as the AComm, which irrigate the caudate nucleus and the anterior limb of the internal capsule
• A2: this segment extends from the AComm to the bifurcation forming the pericallosal and callosomarginal arteries. The recurrent artery of Heubner (distal medial striate artery), which irrigate the internal capsule, usually arises at the beginning of this segment near the AComm. 4 branches arise from this segment, the:
  • Orbitofrontal artery (medial frontal basal): Arises first a small distance away from the AComm
  • Frontopolar artery (polar frontal): Arises after the orbitofrontal close to when A2 curves posteriorly over the corpus callosum. Could also originate from the callosal marginal.
• A3: Also termed the pericallosal artery this is one of (or the only) the main terminal branches of the ACA, which extends posteriorly in the pericallosal sulcus to form the internal parietal arteries (superior, inferior) and the precuneal artery. This artery may form an anastomosis with the posterior cerebral artery.
  • Callosal marginal artery: A commonly present terminal branch of the ACA, which bifurcates from the pericallosal artery. This artery in turn branches into the medial frontal arteries (Anterior, Intermediate, Posterior), and the paracentral artery, with the cingulate branches arising throughout its length. Depending on anatomical variation, the callosal marginal artery may be none discrete or not be visible. In the latter case, the branches mentioned will originate from the pericallosal artery. In a study of 76 hemispheres, the artery was present in only 60% of the cases.^[2] Angiography studies cite that the vessel can be seen 67% ^[1] or 50%^[3] of the time.

Areas supplied

Areas supplied by the anterior cerebral artery include:^{[citation needed]}

1. The medial surface of the frontal lobe by the medial orbito-frontal artery, and parietal lobes
2. The anterior four- fifths of the corpus callosum
3. Approximately 1 inch of the lateral surface of frontal and parietal lobe next to the medial longitudinal fissure
4. Anterior portions of the basal ganglia and internal capsule
5. Olfactory bulb and tract

Occlusion

Occlusion of the anterior cerebral artery may result in the following defects:^{[citation needed] [4]} If stroke occurs prior to the anterior communicating artery it is usually well tolerated secondary to collateral circulation. Occlusion of A2 segment(Post communal segment of Anterior cerebral artery) the following signs and symptoms ma be noted.

1. Paralysis or weakness of the contralateral foot and leg due to involvement of Motor leg area
2. Cortical Sensory loss in the contralateral foot and leg
3. Gait apraxia Impairtment of gait and stance
4. Abulia akinetic mutism, slowness and lack of spontaneity
5. Urinary incontinence which usually occurs with bilateral damage in the acute phase
6. Frontal Cortical release reflexes: Contralateral grasp reflex, sucking reflex, gegenhalten(paratonic rigidity)

Additional images

Anterior cerebral artery   Medial surface of cerebral hemisphere, showing areas supplied by cerebral arteries. Areas supplied by the anterior cerebral artery are shown in blue.   Anterior view of cerebral circulation, including rough courses of A1, A2, and A3 with pericallosal and supracallosal branches.

References

External links

• MedEd at Loyola Neuro/neurovasc/navigation/aca.htm
• SUNY Labs 28:09-0218
• Atlas of anatomy at UMich n3a8p1
• Roche Lexicon - illustrated navigator, at Elsevier 13048.000-1
• Roche Lexicon - illustrated navigator, at Elsevier 13048.000-3

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