Anterior cerebral artery
Updates to Article Attributes
The anterior cerebral artery(ACA), along with the middle cerebral artery (MCA) forms forms at the termination of the internal carotid artery (ICA). It is the smaller of the two and arches anteromedially to pass anterior to the genu of the corpus callosum, dividing as it does so into its two major branches: the pericallosal and callosomarginal arteries.
It supplies the medial aspect of the cerebral hemispheres back to the parietal lobe.
Summary
origin:termination of the internal carotid artery
course:from the medial end of the lateral fissure stem to the corpus callosum
-
main branches
supply:
thethe corpus callosum, the septum pellucidum, the putamen (anterior portion), the head of the caudate nucleus, and parts of the internal capsule
Gross anatomy
Segments
The anterior cerebral artery is divided into five segments 8-10:
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A1: horizontal or pre-communicating segment
originating from the terminal bifurcation of the internal carotid artery, extending ~14 mm in length
terminates at the anterior communicating artery
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A2: vertical, post-communicating or infracallosal segment
originating at the anterior communicating artery, extending anterior to the lamina terminalis and along the rostrum of the corpus callosum
terminates either at the junction of the rostrum and genu of the corpus callosum at the apex of the dorsal convex arch, or at the origin of the callosomarginal artery
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A3:
precallosalprecallosal segmentextends around the genu of the corpus callosum, or originates distal to the origin of the callosomarginal artery
terminates where the artery turns directly posterior above the corpus callosum
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A4:
supracallosalsupracallosal segmentabove the body of the corpus callosum anterior to the plane of the coronal suture
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A5:postcallosal segment
above the body of the corpus callosum posterior to the plane of the coronal suture
The pericallosal artery refers refers either to the distal part of the ACA starting from A2 (after the origin of the anterior communicating artery) or from A3 (defined after the origin of the callosomarginal artery). In the former case, the A2, A3, and A4-5 segments refer to proximal, middle, and distal segments of the pericallosal artery, respectively 11,12.
The A4 and A5 segments predominantly run along the callosal sulcus, but in a minority of cases run above that, medial to the cingulate gyrus.
Branches
There are two main branching patterns of the anterior cerebral artery. In the first, the A2 gives off the callosomarginal artery (which lies in the cingulate sulcus) and continues as the pericallosal artery. In this configuration, the terminal (cortical) branches arise from the callosomarginal artery.
In the second configuration, the callosomarginal artery is absent and the terminal branches arise directly from the pericallosal artery.
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A1
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A2
recurrent artery of Heubner(may arise from distal A1 segment or proximal A2)
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A3
callosomarginal artery (runs in the cingulate sulcus)
Terminal (cortical) branches
Orbital branches, 2 or 3 in number, branch over the orbital surface of the frontal lobe supplying:
olfactory cortex
They are named:
Frontal branches supply:
-
corpus callosum (with the exception of the splenium)
paracentral lobule (as the branches reach over the vertex to supply a strip of cortex on the surface, they are responsible for supply to the lower limbs)
Parietal branches supply:
Central branches
Multiple small branches are given off proximally (A1, ACom, proximal A2) supply:
rostrum of the corpus callosum
anterior part of the putamen
head of the caudate nucleus
anteromedial part of the anterior limb of the internal capsule
The latter two - head of caudate and adjacent part of the internal capsule - are are supplied by the recurrent artery of Heubner and associated smaller perforating branches. It has its origin near the A1-ACom-A2 junction and can arise from all three, although usually, it is from the A2. It curves back on itself and is at risk of ACom aneurysm clipping.
Variant anatomy
ACA fenestration
withwith a reported incidence of 0-4% of A1 segment fenestrationazygos ACA: ACA territories supplied by a single A2 trunk; incidence of ~2% (range 0.2-4%)
ACA trifurcation: three A2 segments; incidence of ~7.5% (range 2-13%)
bihemispheric ACA: a hypoplastic A2 segment with contralateral A2 segment dominance supplying both ACA territories; incidence of ~4.5% (range 2-7%)
A1 segment absence/hypoplasia, contralateral A1 segment dominance and supply to ipsilateral A2 segment by a large anterior communicating artery: 10% of individuals demonstrate hypoplasia of A1 segment using a diameter 1.5 mm or smaller
duplication of A1
two or three anterior communicating arteries
asymmetry of A1 segment which is associated with ACA aneurysm
-<p>The<strong> anterior cerebral artery</strong> (<strong>ACA</strong>), along with the <a href="/articles/middle-cerebral-artery">middle cerebral artery (MCA)</a> forms at the termination of the <a href="/articles/internal-carotid-artery-1">internal carotid artery (ICA)</a>. It is the smaller of the two and arches anteromedially to pass anterior to the genu of the <a href="/articles/corpus-callosum">corpus callosum</a>, dividing as it does so into its two major branches: the <a href="/articles/pericallosal-artery" title="Pericallosal artery">pericallosal</a> and <a href="/articles/callosomarginal-artery" title="Callosomarginal artery">callosomarginal</a> arteries. </p><p>It supplies the medial aspect of the cerebral hemispheres back to the parietal lobe.</p><h4>Summary</h4><ul>-<li><p><strong>origin: </strong>termination of the <a href="/articles/internal-carotid-artery-1">internal carotid artery</a></p></li>-<li><p><strong>course: </strong>from the medial end of the lateral fissure stem to the corpus callosum</p></li>- +<p>The<strong> anterior cerebral artery</strong> (<strong>ACA</strong>), along with the <a href="/articles/middle-cerebral-artery">middle cerebral artery (MCA)</a> forms at the termination of the <a href="/articles/internal-carotid-artery-1">internal carotid artery (ICA)</a>. It is the smaller of the two and arches anteromedially to pass anterior to the genu of the <a href="/articles/corpus-callosum">corpus callosum</a>, dividing as it does so into its two major branches: the <a href="/articles/pericallosal-artery" title="Pericallosal artery">pericallosal</a> and <a href="/articles/callosomarginal-artery" title="Callosomarginal artery">callosomarginal</a> arteries. </p><p>It supplies the medial aspect of the cerebral hemispheres back to the parietal lobe.</p><h4>Summary</h4><ul>
- +<li><p><strong>origin: </strong>termination of the <a href="/articles/internal-carotid-artery-1">internal carotid artery</a></p></li>
- +<li><p><strong>course: </strong>from the medial end of the lateral fissure stem to the corpus callosum</p></li>
-<li><p><a href="/articles/recurrent-artery-of-heubner-1">recurrent artery of Heubner</a> </p></li>- +<li><p><a href="/articles/recurrent-artery-of-heubner-1">recurrent artery of Heubner</a> </p></li>
-<li><p><strong>supply:</strong> the corpus callosum, the septum pellucidum, the putamen (anterior portion), the head of the caudate nucleus, and parts of the internal capsule</p></li>- +<li><p><strong>supply:</strong> the corpus callosum, the septum pellucidum, the putamen (anterior portion), the head of the caudate nucleus, and parts of the internal capsule</p></li>
-<p><strong>A3: precallosal segment</strong></p>- +<p><strong>A3: precallosal segment</strong></p>
-<p><strong>A4: supracallosal segment</strong></p>- +<p><strong>A4: supracallosal segment</strong></p>
-<p><strong>A5: postcallosal segment</strong></p>- +<p><strong>A5: postcallosal segment</strong></p>
-</ul><p>The <a href="/articles/pericallosal-artery">pericallosal artery</a> refers either to the distal part of the ACA starting from A2 (after the origin of the anterior communicating artery) or from A3 (defined after the origin of the callosomarginal artery). In the former case, the A2, A3, and A4-5 segments refer to proximal, middle, and distal segments of the pericallosal artery, respectively <sup>11,12</sup>.</p><p>The A4 and A5 segments predominantly run along the callosal sulcus, but in a minority of cases run above that, medial to the cingulate gyrus.</p><h5>Branches</h5><p>There are two main branching patterns of the anterior cerebral artery. In the first, the A2 gives off the callosomarginal artery (which lies in the cingulate sulcus) and continues as the pericallosal artery. In this configuration, the terminal (cortical) branches arise from the callosomarginal artery.</p><p>In the second configuration, the callosomarginal artery is absent and the terminal branches arise directly from the pericallosal artery.</p><ul>- +</ul><p>The <a href="/articles/pericallosal-artery">pericallosal artery</a> refers either to the distal part of the ACA starting from A2 (after the origin of the anterior communicating artery) or from A3 (defined after the origin of the callosomarginal artery). In the former case, the A2, A3, and A4-5 segments refer to proximal, middle, and distal segments of the pericallosal artery, respectively <sup>11,12</sup>.</p><p>The A4 and A5 segments predominantly run along the callosal sulcus, but in a minority of cases run above that, medial to the cingulate gyrus.</p><h5>Branches</h5><p>There are two main branching patterns of the anterior cerebral artery. In the first, the A2 gives off the callosomarginal artery (which lies in the cingulate sulcus) and continues as the pericallosal artery. In this configuration, the terminal (cortical) branches arise from the callosomarginal artery.</p><p>In the second configuration, the callosomarginal artery is absent and the terminal branches arise directly from the pericallosal artery.</p><ul>
-<li><p><a href="/articles/anterior-communicating-artery">anterior communicating artery</a> </p></li>- +<li><p><a href="/articles/anterior-communicating-artery">anterior communicating artery</a> </p></li>
-<li><p><a href="/articles/recurrent-artery-of-heubner-1">recurrent artery of Heubner</a> (may arise from distal A1 segment or proximal A2)</p></li>- +<li><p><a href="/articles/recurrent-artery-of-heubner-1">recurrent artery of Heubner</a> (may arise from distal A1 segment or proximal A2)</p></li>
-</ul><p>The latter two - head of caudate and adjacent part of the internal capsule - are supplied by the <a href="/articles/recurrent-artery-of-huebner">recurrent artery of Heubner</a> and associated smaller perforating branches. It has its origin near the A1-ACom-A2 junction and can arise from all three, although usually, it is from the A2. It curves back on itself and is at risk of ACom <a href="/articles/intracranial-aneurysm-overview" title="Cerebral aneurysm">aneurysm</a> clipping.</p><h4>Variant anatomy</h4><ul>-<li><p>ACA <a href="/articles/intracranial-arterial-fenestration">fenestration</a> with a reported incidence of 0-4% of A1 segment fenestration</p></li>- +</ul><p>The latter two - head of caudate and adjacent part of the internal capsule - are supplied by the <a href="/articles/recurrent-artery-of-huebner">recurrent artery of Heubner</a> and associated smaller perforating branches. It has its origin near the A1-ACom-A2 junction and can arise from all three, although usually, it is from the A2. It curves back on itself and is at risk of ACom <a href="/articles/intracranial-aneurysm-overview" title="Cerebral aneurysm">aneurysm</a> clipping.</p><h4>Variant anatomy</h4><ul>
- +<li><p>ACA <a href="/articles/intracranial-arterial-fenestration">fenestration</a> with a reported incidence of 0-4% of A1 segment fenestration</p></li>
-<li><p><a href="/articles/persistent-primitive-olfactory-artery">persistent primitive olfactory artery</a> <sup>6</sup></p></li>- +<li><p><a href="/articles/persistent-primitive-olfactory-artery">persistent primitive olfactory artery</a> <sup>6</sup></p></li>
Image 15 CT ( VR images) ( create )
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