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Posterior parietal artery

The Posterior Parietal Artery is one of the cortical branches of the middle cerebral artery (MCA) and is responsible for supplying blood to the posterior part of the parietal lobe, particularly the superior parietal lobule and sometimes parts of the angular gyrus. Its anatomical variations and contributions make it significant in both neurovascular anatomy and in clinical contexts such as ischemic stroke and neurosurgical planning. Identification of the posterior parietal artery on imaging is crucial, especially during the assessment of parietal lobe lesions and cerebrovascular events.

Synonyms

  • Posterior parietal cortical branch of the middle cerebral artery

  • Posterior parietal branch of MCA

  • Parietal posterior branch (less common)

Origin and Course

  • Arises from the middle cerebral artery (usually the M4 segment, which is the cortical segment).

  • Most frequently, it originates from the superior division of the MCA.

  • The artery travels posteriorly along the superior aspect of the parietal lobe, primarily supplying the superior parietal lobule and sometimes contributing to the angular gyrus.

  • May anastomose with branches of the anterior cerebral artery (especially the paracentral branch) and the posterior cerebral artery (parieto-occipital branches).

Function

  • Provides arterial blood supply to the posterior portion of the parietal lobe, especially:

    • Superior parietal lobule (Brodmann areas 5 and 7)

    • Posterior part of the intraparietal sulcus

    • Occasionally, the angular gyrus (Brodmann area 39)

  • Supports functions related to spatial orientation, visuomotor coordination, attention, and integration of sensory information.

MRI Appearance

  • Not directly visible as a discrete artery on standard MRI sequences.

  • May be visualized using MR angiography (MRA) as a small, superficial cortical branch running over the superior parietal cortex.

  • In cases of infarction, the supplied region shows restricted diffusion (DWI/ADC) in the superior and posterior parietal lobe.

  • Contrast-enhanced MRA or high-resolution 3D TOF MRA may show the vessel and its distribution in detail.

CT Appearance

  • Not typically visible on non-contrast CT due to its small size.

  • Can sometimes be seen as a thin enhancing branch on CT angiography (CTA), particularly in detailed vascular studies.

  • In cases of infarct, the area supplied will show hypodensity in the parietal lobe on non-contrast CT.

  • CTA is useful in acute stroke settings to assess patency or occlusion of cortical branches like the posterior parietal artery.

MRI image

Posterior parietal artery MRI 3T coronal image