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Paracentral sulcus

The paracentral sulcus is a prominent groove located on the medial surface of the cerebral hemisphere, adjacent to the central sulcus. It forms the anterior border of the paracentral lobule, separating it from the superior frontal gyrus. The paracentral sulcus is considered an important anatomical landmark in neuroimaging and neurosurgery, as it helps delineate the regions responsible for motor and sensory functions of the lower limb. Its appearance and boundaries may show individual variation, but its relationship with surrounding gyri and sulci remains critical for brain mapping.

Synonyms

  • Sulcus paracentralis

  • Paracentral groove

  • Medial precentral sulcus (less commonly)

Function

  • Anatomical boundary: Marks the anterior limit of the paracentral lobule.

  • Separates motor and sensory areas associated with the lower extremities.

  • Serves as a surgical landmark in procedures involving the medial cerebral hemisphere.

  • Helps in the identification of functional cortical areas on imaging.

Arterial Supply

  • Supplied mainly by branches of the anterior cerebral artery (ACA), particularly the pericallosal and callosomarginal arteries.

  • Small cortical branches ensure perfusion to the adjacent medial frontal and paracentral regions.

Venous Drainage

  • Drained by superior sagittal sinus via cortical veins.

  • The medial cerebral hemisphere’s superficial veins, including the paracentral sulcus region, primarily drain into the superior sagittal sinus.

MRI Appearance

  • T1-Weighted Images:

    • The paracentral sulcus appears as a hypointense (dark) groove separating gyri, filled with cerebrospinal fluid (CSF).

    • The sulcus clearly demarcates the adjacent cortex of the paracentral lobule and superior frontal gyrus.

  • T2-Weighted Images:

    • The sulcus appears hyperintense (bright) due to CSF signal, providing excellent contrast with the surrounding gray and white matter.

    • Useful in identifying subtle anatomical variations.

  • FLAIR Images:

    • The paracentral sulcus is seen as a low-signal (dark) line because CSF signal is suppressed.

    • Helps to differentiate sulci from periventricular or cortical pathology, which appears hyperintense.

CT Appearance

  • Appears as a linear hypodense (dark) structure on non-contrast CT, representing CSF within the sulcus.

  • Paracentral sulcus can be identified by following the medial aspect of the hemisphere, anterior to the central sulcus, but is less conspicuous than on MRI.

MRI images

Paracentral sulcus MRI 3T axial image

MRI images

Paracentral sulcus MRI 3T sagittal image