Anterior cerebral artery

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The anterior cerebral artery (ACA) along with the middle cerebral artery (MCA) 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; pericallosal and callosomarginal arteries (see below).

It supplies the medial aspect of the cerebral hemispheres back to the parietal lobe.

Gross anatomy

Segments

The anterior cerebral artery is divided into five segments ^8-10:

A1: horizontal or pre-communicating segment
- originating from the terminal bifurcation of the ICA, extending ~14 mm in length
- terminates at the anterior communicating artery (ACOM)
A2: vertical, post-communicating or infracallosal segment
- originating at the ACOM, extending anterior to the lamina terminalis and along the rostrum of the corpus callosum
- terminates either at the genu of the corpus callosum or at the origin of the callosomarginal artery
A3: precallosal segment
- extends around the genu of the corpus callosum or distal to the origin of the callosomarginal artery
- terminates where the artery turns directly posterior above the corpus callosum
A4: supracallosal segment
- above the body of the corpus callosum anterior to the plane of the coronal suture
A5: postcallosal segment
- above the body of the corpus callosum posterior to the plane of the coronal suture

The pericallosal artery refers either to the distal part of the ACA starting from A2 (after the origin of the ACOM) 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 are given off the callosomarginal artery.

In the second configuration, the callosomarginal is absent and the terminal branches arise directly from the pericallosal.

A1
- medial lenticulostriate arteries
- anterior communicating artery
A2
A3
- pericallosal artery
- 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:

They are named:

Frontal branches supply:

corpus callosum (with the exception of the splenium)
- pericallosal artery
cingulate gyrus
medial frontal gyrus
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:

precuneus

Central branches

Multiple small branches are given off proximally (A1, ACOM, proximal A2) supply:

anterior perforated substance
lamina terminalis
rostrum of the corpus callosum
septum pellucidum
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 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 from ACOM aneurysm clipping.

Variant anatomy

ACA fenestration with a reported incidence of 0-4% of A1 segment fenestration
azygos ACA: ACA territories supplied by a single A2 trunk; incidence of ~2% (range 0.2-4.0%)
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
persistent primitive olfactory artery ⁶

-</ul>Parietal branches supply:<ul><li><a href="/articles/precuneus">precuneus</a></li></ul><h6>Central branches</h6>Multiple small branches are given off proximally (A1, ACOM, proximal A2) supply:<ul>
+</ul>Parietal branches supply:<ul><li><a href="/articles/precuneus-1">precuneus</a></li></ul><h6>Central branches</h6>Multiple small branches are given off proximally (A1, ACOM, proximal A2) supply:<ul>

References changed:

1. Henry Gray, Patricia Collins. Gray's Anatomy. (2005) ISBN: 9780443071683 - <a href="http://books.google.com/books?vid=ISBN9780443071683">Google Books</a>
2. Kang H, Han M, Kwon B, Kwon O, Kim S, Chang K. Evaluation of the Lenticulostriate Arteries with Rotational Angiography and 3D Reconstruction. AJNR Am J Neuroradiol. 2005;26(2):306-12. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7974073">PMC7974073</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/15709128">Pubmed</a>
3. Hans-Joachim Kretschmann, Wolfgang Weinrich. Cranial Neuroimaging and Clinical Neuroanatomy. (2004) ISBN: 9781588901453 - <a href="http://books.google.com/books?vid=ISBN9781588901453">Google Books</a>
4. Julien Bogousslavsky. Stroke Syndromes. (2001) ISBN: 9780521771429 - <a href="http://books.google.com/books?vid=ISBN9780521771429">Google Books</a>
5. Hugo Krayenbühl, Peter Huber, Mahmut Gazi Yaşargil. Cerebral Angiography. (1982) ISBN: 9780865770676 - <a href="http://books.google.com/books?vid=ISBN9780865770676">Google Books</a>
6. Dimmick S & Faulder K. Normal Variants of the Cerebral Circulation at Multidetector CT Angiography. Radiographics. 2009;29(4):1027-43. <a href="https://doi.org/10.1148/rg.294085730">doi:10.1148/rg.294085730</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/19605654">Pubmed</a>
7. Paul Butler, Adam Mitchell, Jeremiah C. Healy. Applied Radiological Anatomy. (2012) ISBN: 9780521766661 - <a href="http://books.google.com/books?vid=ISBN9780521766661">Google Books</a>
8. Alfredo Quiñones-Hinojosa. Schmidek and Sweet: Operative Neurosurgical Techniques 2-Volume Set,Indications, Methods and Results (Expert Consult - Online and Print),6. (2012) ISBN: 9781416068396 - <a href="http://books.google.com/books?vid=ISBN9781416068396">Google Books</a>
9. Perlmutter D & Rhoton A. Microsurgical Anatomy of the Distal Anterior Cerebral Artery. J Neurosurg. 1978;49(2):204-28. <a href="https://doi.org/10.3171/jns.1978.49.2.0204">doi:10.3171/jns.1978.49.2.0204</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/671075">Pubmed</a>
10. Kakou M, Destrieux C, Velut S. Microanatomy of the Pericallosal Arterial Complex. J Neurosurg. 2000;93(4):667-75. <a href="https://doi.org/10.3171/jns.2000.93.4.0667">doi:10.3171/jns.2000.93.4.0667</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/11014546">Pubmed</a>
11. Pfaff J, Herweh C, Pham M et al. Mechanical Thrombectomy of Distal Occlusions in the Anterior Cerebral Artery: Recanalization Rates, Periprocedural Complications, and Clinical Outcome. AJNR Am J Neuroradiol. 2016;37(4):673-8. <a href="https://doi.org/10.3174/ajnr.A4594">doi:10.3174/ajnr.A4594</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/26542233">Pubmed</a>
12. Lehecka M, Dashti R, Hernesniemi J et al. Microneurosurgical Management of Aneurysms at the A2 Segment of Anterior Cerebral Artery (Proximal Pericallosal Artery) and Its Frontobasal Branches. Surg Neurol. 2008;70(3):232-46; discussion 246. <a href="https://doi.org/10.1016/j.surneu.2008.03.008">doi:10.1016/j.surneu.2008.03.008</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/18486199">Pubmed</a>
1. Gray's anatomy. Churchill Livingstone. (2005) ISBN:0443071683. <a href="http://books.google.com/books?vid=ISBN0443071683">Read it at Google Books</a> - <a href="http://www.amazon.com/gp/product/0443071683">Find it at Amazon</a>
2. Kang HS, Han MH, Kwon BJ et-al. Evaluation of the lenticulostriate arteries with rotational angiography and 3D reconstruction. (2005) AJNR. American journal of neuroradiology. 26 (2): 306-12. <a href="https://www.ncbi.nlm.nih.gov/pubmed/15709128">Pubmed</a>
3. Hans-Joachim Kretschmann, Wolfgang Weinrich. Cranial Neuroimaging and Clinical Neuroanatomy. (2020) <a href="https://books.google.co.uk/books?vid=ISBN9781588901453">ISBN: 9781588901453</a>
4. Julien Bogousslavsky, Louis R. Caplan. Stroke Syndromes. (2001) <a href="https://books.google.co.uk/books?vid=ISBN9780521771429">ISBN: 9780521771429</a>
5. Hugo Krayenbühl, Mahmut Gazi Yaşargil, Peter Huber. Cerebral Angiography. (1982) <a href="https://books.google.co.uk/books?vid=ISBN9780865770676">ISBN: 9780865770676</a>
6. Dimmick SJ, Faulder KC. Normal variants of the cerebral circulation at multidetector CT angiography. Radiographics. 2009;29 (4): 1027-43. <a href="http://radiographics.rsna.org/content/29/4/1027.full">Radiographics (full text)</a> - <a href="http://dx.doi.org/10.1148/rg.294085730">doi:10.1148/rg.294085730</a> - <a href="http://www.ncbi.nlm.nih.gov/pubmed/19605654">Pubmed citation</a>
7. Butler P, Mitchell A, Healy JC. Applied Radiological Anatomy. Cambridge University Press. (2012) ISBN:0521766664. <a href="http://books.google.com/books?vid=ISBN0521766664">Read it at Google Books</a> - <a href="http://www.amazon.com/gp/product/0521766664">Find it at Amazon</a>
8. Alfredo Quinones-Hinojosa. Schmidek and Sweet: Operative Neurosurgical Techniques. (2020) <a href="https://books.google.co.uk/books?vid=ISBN9781416068396">ISBN: 9781416068396</a>
9. Perlmutter D, Rhoton AL. Microsurgical anatomy of the distal anterior cerebral artery. (1978) Journal of neurosurgery. 49 (2): 204-28. <a href="https://doi.org/10.3171/jns.1978.49.2.0204">doi:10.3171/jns.1978.49.2.0204</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/671075">Pubmed</a>
10. Kakou M, Destrieux C, Velut S. Microanatomy of the pericallosal arterial complex. (2000) Journal of neurosurgery. 93 (4): 667-75. <a href="https://doi.org/10.3171/jns.2000.93.4.0667">doi:10.3171/jns.2000.93.4.0667</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/11014546">Pubmed</a>
11. J. Pfaff, C. Herweh, M. Pham et-al. Mechanical Thrombectomy of Distal Occlusions in the Anterior Cerebral Artery: Recanalization Rates, Periprocedural Complications, and Clinical Outcome. (2016) American Journal of Neuroradiology. 37 (4): 673. <a href="https://doi.org/10.3174/ajnr.A4594">doi:10.3174/ajnr.A4594</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/26542233">Pubmed</a>
12. Lehecka M, Dashti R, Hernesniemi J et-al. Microneurosurgical management of aneurysms at the A2 segment of anterior cerebral artery (proximal pericallosal artery) and its frontobasal branches. (2008) Surgical neurology. 70 (3): 232-46; discussion 246. <a href="https://doi.org/10.1016/j.surneu.2008.03.008">doi:10.1016/j.surneu.2008.03.008</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/18486199">Pubmed</a>

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