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Precuneus

The precuneus is a prominent structure located on the medial surface of the parietal lobe, situated between the cingulate gyrus and the parieto-occipital sulcus. Despite being less discussed in classic neurology, it plays a vital role in higher-order brain functions, including visuospatial processing, episodic memory retrieval, self-related mental representations, and aspects of consciousness. The precuneus is a key component of the default mode network, making it essential in studies of resting-state brain activity.

Synonyms:

  • Medial parietal cortex (informal)

  • Paracentral area (historically, but less precise)

Arterial Supply:

  • Primarily supplied by the pericallosal branch of the anterior cerebral artery (ACA).

  • May also receive contributions from the parieto-occipital branch of the posterior cerebral artery (PCA), especially posteriorly.

Venous Drainage:

  • Drained mainly via the superior sagittal sinus.

  • Also drains into the subependymal veins and then into the internal cerebral veins.

Function:

  • Involved in visuospatial imagery and spatial orientation.

  • Plays a role in episodic memory retrieval.

  • Contributes to self-consciousness and reflective thought.

  • Acts as a hub in the default mode network for baseline/resting state brain activity.

MRI Appearance:

  • T1-weighted MRI:

    • Appears as gray matter (intermediate signal intensity) bordering the midline, easily distinguished from surrounding white matter.

    • Anatomical boundaries best visualized on sagittal images.

  • T2-weighted MRI:

    • Gray matter of the precuneus demonstrates slightly higher signal compared to white matter.

    • Sulci and adjacent parietal structures may enhance anatomical definition.

  • FLAIR (Fluid-Attenuated Inversion Recovery):

    • Similar to T2, but with suppression of cerebrospinal fluid (CSF) signal in sulci.

    • Lesions, demyelination, or infarcts are better visualized due to higher contrast between cortex and CSF.

​CT Appearance

  • The precuneus appears as slightly hyperintense compared to white matter, due to higher cellular density and blood volume typical of cortical gray matter

MRI images

Precuneus mri 3t axial image

MRI images

Precuneus mri 3t sagittal image

CT image

Precuneus CT sag cross sectional anatomy radiology image -img-00001-00001