Posterior cerebral artery

Changed by Andrew Dixon, 22 Jun 2018

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The posterior cerebral arteries (PCA) are the terminal branches of the basilar artery and supply the occipital lobes and posteromedial temporal lobes.

Summary

origin: terminal branches of the basilar artery
course: from basilar towards occiput
main branches
supply: occipital lobes and posteromedial temporal lobes

Gross anatomy

The PCA is divided into four segments:

P1: from it origin at the termination of the basilar artery to posterior communicating artery (PCOM), within interpeduncular cistern
P2: from the PCOM around the midbrain
- P2A (anterior) sub-segment within the crural cistern
- P2P (posterior, ambient) sub-segment in the ambient cistern
P3: quadrigeminal segment (segment within the quadrigeminal cistern)
P4: cortical segment (e.g. calcarine artery, within the calcarine fissure)

Branches

posterior communicating artery
choroidal branches (from P2)
- medial posterior choroidal arteries
- lateral posterior choroidal arteries
perforators
- anterior thalamoperforator (from PCOM)
- posterior thalamoperforator (from P1)
- thalamogeniculate perforator (from P2)
- peduncular perforator (from P2)
- circumflex (long and short)
cortical branches
- temporal branches
  - anterior temporal artery
  - posterior temporal artery
- lateral occipital artery
  - anterior inferior temporal artery
  - middle inferior temporal artery
  - posterior inferior temporal artery
- medial occipital artery
  - calcarine artery
  - parieto-occipital artery
- splenial artery

Supply

The posterior cerebral artery curls around the cerebral peduncle and passes above the tentorium to supply the posteromedial surface of the temporal lobe and the occipital lobe. The visual cortex responsible for the contralateral field of vision lies in its territory. The macular part of the visual cortex often receives a dual blood supply from the PCA and the MCA, which explains the "macular sparing" phenomenon in some patients following a PCA infarct.

Variant anatomy

~~PCA fenestration: rare~~
fetal origin of PCA: unilateral incidence 10%, bilateral incidence 8%

PCA fenestration: rare

duplicated PCA: rare, fetal origin and normal origin on same side ⁶

~~-<li>P2P (posterior, ambient) sub-segment in the <a title="Ambient cistern" href="/articles/ambient-cistern">ambient cistern</a>~~
+<li>P2P (posterior, ambient) sub-segment in the <a href="/articles/ambient-cistern">ambient cistern</a>
~~-<li>PCA fenestration: rare</li>~~
+<li>PCA fenestration: rare</li>
+<li>duplicated PCA: rare, fetal origin and normal origin on same side <sup>6</sup>
+</li>

References changed:

6. Masoud H, Nguyen T, Thatcher J, Barest G, Norbash A. Duplication of the Posterior Cerebral Artery and the 'True Fetal' Variant. Interv Neurol. 2015;4(1-2):64-7. <a href="https://doi.org/10.1159/000437310">doi:10.1159/000437310</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/26600800">Pubmed</a>

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