Fetal posterior communicating cerebral artery

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

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 case of non fetal PCA, the PCOM lies superomedial to the occulomotor nerve, whereas in case of fetal PCA, it lies superior or superolateral to the occulomotor nerve.


Neuroanatomy
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Article Information

rID: 4914
Section: Anatomy
Tags: refs, rewrite
Synonyms or Alternate Spellings:
  • Fetal PCOM
  • Fetal posterior comminucating artery
  • Fetal origin of posterior cerebral artery
  • Fetal P-comm

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    Case 3 : fetal PCA with para PCom aneurysm
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    Case 3: infarction consequences of fetal PCA
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    Case 7: bilateral fetal Pcomms
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