Anterior communicating artery

The anterior communicating artery (ACOM) arises from the anterior cerebral artery and acts as an anastomosis between the left and right anterior cerebral circulation. Approximately 4 mm in length, it demarcates the junction between the A1 and A2 segments of the anterior cerebral artery.


The ACOM gives off numerous small branches that go on to supply the following structures:

Variant anatomy

  • ACOM duplication: incidence 18%
  • ACOM fenestration: incidence ~15% (range 12-21%)
  • ACA trifurcation arising from the ACOM: incidence ~7.5% (range 2-13%)
  • absent ACOM: incidence 5% (surgical dissection) 2

If the vessel is not well seen on routine angiography, cross-compression view of the ACA/ACOM complex can be performed.

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Article information

rID: 4804
Section: Anatomy
Synonyms or Alternate Spellings:
  • Anterior communicating artery (ACOM)
  • ACOM

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Cases and figures

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    Figure 1: diagram - basilar artery and circle of Willis
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    Cross Compression
    Figure 2: angiogram
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    Figure 3: ACOM fenestration
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    Figure 4: ACOM aneurysm
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    Figure 5
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    Figure 6: absent ACOM with fenestrated A1 on right common A2 trunk
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