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Posteromedial central (perforating) arteries

The posteromedial central (perforating) arteries are small but crucial branches of the posterior cerebral circulation, playing a vital role in the vascular supply to deep midline structures of the brain. Despite their small size, they are clinically significant because they supply key areas such as the thalamus, hypothalamus, subthalamus, and parts of the internal capsule. Infarcts or injuries involving these arteries can result in profound neurological deficits due to the importance of the structures they perfuse.

Synonyms

  • Posterior thalamoperforating arteries

  • Thalamoperforating arteries (when context is clear)

  • Central perforating arteries (posteromedial group)

  • Medial posterior perforating arteries

Origin

  • Originate from the P1 segment of the posterior cerebral artery (PCA), which is the portion between the basilar artery bifurcation and the junction with the posterior communicating artery.

  • Occasionally, may also receive contributions from the posterior communicating artery itself.

Course

  • Arise near the interpeduncular fossa at the base of the brain.

  • Penetrate the posterior perforated substance, a region at the base of the midbrain situated between the cerebral peduncles.

  • Course dorsally and medially to supply deep midline structures, particularly in the diencephalon.

Function / Areas Supplied

  • Thalamus: Medial and anterior nuclei, contributing to sensory relay and regulatory functions.

  • Hypothalamus: Important in endocrine and autonomic control.

  • Subthalamus and Subthalamic Nucleus: Important in motor function regulation.

  • Mammillary bodies

  • Posterior limb of the internal capsule (anterior and medial portions)

  • Other adjacent structures: Such as the optic tract and portions of the midbrain.

MRI Appearance

  • Normal: The arteries themselves are not visualized on routine MRI due to their small caliber.

  • Pathology (Infarct): Acute ischemia in their territory appears as restricted diffusion (hyperintense on DWI, hypointense on ADC), most commonly in the paramedian thalamus and adjacent structures.

  • MR Angiography (MRA): May occasionally show the larger branches, but most are below the resolution of standard clinical imaging.

CT Appearance

  • Normal: Not directly visualized due to their size.

  • Pathology (Infarct): May show hypodensity in the paramedian thalamus or midbrain, depending on the extent and duration of ischemia.

  • CT Angiography (CTA): Larger branches may be faintly seen, but not reliably visualized except with high-resolution or advanced techniques.

MRI image

Posteromedial central (perforating) arteries mri 3t axial image