Fetal posterior cerebral artery

A fetal (origin of the) posterior cerebral artery is a common variant in the posterior cerebral circulation, estimated to occur in 20-30% of individuals 2.

The posterior communicating artery (PCOM) is larger than the P1 segment of the posterior cerebral artery (PCA) and supplies the bulk of the blood to the PCA. If bilateral, the basilar artery is significantly smaller than normal. 

The term is typically used to refer to the situation where the PCOM is larger than the P1. However, variation in usage abounds.

The P1 can be small (hypoplastic) or absent. The significance is in the stroke pattern, as the PCA is therefore part of the anterior circulation. Additionally a larger PCOM (with P1 present) allows for collateral circulation.

In cases of non-fetal PCA, the PCOM lies superomedial to the oculomotor nerve, whereas in cases of fetal PCA, it lies superior or superolateral to the oculomotor nerve.

Anatomy: Brain

Anatomy: Brain

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Article information

rID: 4914
Synonyms or Alternate Spellings:
  • Fetal PCOM
  • Fetal posterior comminucating artery
  • Fetal origin of posterior cerebral artery
  • Fetal P-comm

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Cases and figures

  • Figure 1
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  • Case 1
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  • Case 2
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  • Bone - overlapped
    Case 3 : fetal PCA with para PCom aneurysm
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  • Case 3: infarction consequences of fetal PCA
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  • Case 4
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  • Case 5
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  • Case 6
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  • Case 7: bilateral fetal Pcomms
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