Posterior Communicating Artery

VESSEL PATHWAY

The posterior communicating artery is a component of the circle of Willis. It connects the internal carotid artery (right before it bifurcates into the ACA and MCA) and the PCA.

Aorta → Brachiocephalic  (only on right) → Common Carotid → Internal Carotid → Posterior Communicating

Aorta → Brachiocephalic (only on right) → Subclavian → Vertebral Artery → Basilar Artery → PCA → Posterior Communicating

Anatomical location of the posterior communicating artery (source)
Anatomical location of the posterior communicating artery (source)
FUNCTION

Connect the internal carotid artery and the PCA.

CAUSES OF INJURY

Aneurysm of this artery can be caused by…

CLINICAL PRESENTATION OF INJURY

Aneurysm of this artery can compress the oculomotor nerve (CN III) due to very close proximity (this vessel is especially susceptible to this happening). Given also that pupilloconstrictor fibers lie superficially on this nerve, this type of compression injury can manifest as:

  • A tonically dilated pupil, and a deficient pupillary response to both direct and consensual stimulation (shining light in either eye will not cause the affected eye to constrict).
  • Diplopia as the aneurysm enlarges and compresses the nerves that supply the medial rectus muscle.
OTHER INFO

 

Page updated: 06.20.2016