Posterior_communicating_artery

Posterior communicating artery

Posterior communicating artery

Arteries at the base of the brain that form part of the circle of Willis

In human anatomy, the left and right posterior communicating arteries are small[1]: 471  arteries at the base of the brain that form part of the circle of Willis.

Quick Facts Details, Identifiers ...

Anteriorly, it unites with the internal carotid artery (ICA) (prior to the terminal bifurcation of the ICA into the anterior cerebral artery and middle cerebral artery); posteriorly, it unites with the posterior cerebral artery.

With the anterior communicating artery, the posterior communicating arteries establish a system of collateral circulation in cerebral circulation.

Anatomy

The arteries contribute to the blood supply of the optic tract.[1]: 465 

The two posterior communicating arteries often differ in size.[1]: 472 

Relations

Each posterior communicating artery is situated within the interpeduncular cistern, superolateral to the pituitary gland.[2]: 450  Each are is situated upon the medial surface of the ipsilateral cerebral peduncle[1]: 477  and adjacent to the anterior perforated substance.[1]: 471 

The ipsilateral oculomotor nerve (CN III) passes inferolaterally to the artery[1]: 494  (pathology of the artery may thus compress the CN III[3]: 407 ).

Development

The development of the posterior cerebral artery (PCA) in the fetal brain occurs relatively late and arises from the fusion of several embryonic vessels near the caudal end of the posterior communicating artery.

The PCA begins as a continuation of the posterior communicating artery in 70-90% of fetuses with the remainder of PCAs having a basilar origin. The fetal carotid origin of the PCA usually regresses as the vertebral and basilar arteries become dominant and it finds a new origin in the basilar artery. About 20% of adults retain PCA origin from the posterior communicating artery, and in turn, the internal carotid arteries.[4]

Function

The brain is supplied with blood by the internal carotid arteries and also by the posterior cerebral arteries; the posterior communicating arteries connects the two systems. This provides redundancies or collaterals in the cerebral circulation so that, if one system is blocked or narrowed, the other can take over.

Clinical significance

Aneurysms of the posterior communicating artery are the third most common circle of Willis aneurysm[5] (the most common are anterior communicating artery aneurysms) and can lead to oculomotor nerve palsy.[6]

References

  1. [1]
    Sinnatamby, Chummy S. (2011). Last's Anatomy (12th ed.). ISBN 978-0-7295-3752-0.
  2. [2]
    Sinnatamby, Chummy S. (2011). Last's Anatomy (12th ed.). ISBN 978-0-7295-3752-0.
  3. [3]
    Sinnatamby, Chummy S. (2011). Last's Anatomy (12th ed.). ISBN 978-0-7295-3752-0.
  4. [4]
    Osborn, Anne G.; Jacobs, John M. (1999), Diagnostic Cerebral Angiography, Lippincott Williams & Wilkins, pp. 153
  5. [5]
    Beck J, Rohde S, Berkefeld J, Seifert V, Raabe A. Size and location of ruptured and unruptured intracranial aneurysms measured by 3-dimensional rotational angiography. Surg Neurol. 2006 Jan;65(1):18-25; discussion 25-7. PMID 16378842.
  6. [6]
    Dimopoulos VG, Fountas KN, Feltes CH, Robinson JS, Grigorian AA. Literature review regarding the methodology of assessing third nerve paresis associated with non-ruptured posterior communicating artery aneurysms. Neurosurg Rev. 2005 Oct;28(4):256-60. PMID 15947958.
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