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Topic

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Precentral sulcus

The precentral sulcus is a prominent groove in the frontal lobe of the brain, located immediately anterior to the precentral gyrus and running parallel to the central sulcus. It acts as a critical anatomical landmark for dividing the frontal lobe and serves as an important reference point in neuroimaging and neurosurgery. Its position helps distinguish the motor cortex from the premotor and prefrontal regions, aiding in the identification of functional areas during structural or functional brain mapping.

Synonyms

  • Anterior central sulcus

  • Sulcus praecentralis (Latin)

Function

  • Anatomical landmark separating the precentral gyrus (primary motor cortex, Brodmann area 4) from the premotor cortex (Brodmann area 6)

  • Serves as a reference in neurosurgical planning and in neuroimaging for localizing functional areas

  • Helps delineate the boundary between primary motor and premotor areas

Arterial Supply

  • Supplied mainly by branches of the middle cerebral artery (MCA), specifically the precentral branches

  • Occasionally receives small branches from the anterior cerebral artery (ACA), particularly from its callosomarginal artery

Venous Drainage

  • Drained primarily by superior cerebral veins (superficial cortical veins), which empty into the superior sagittal sinus

  • Additional drainage may occur through the middle cerebral vein

MRI Appearance

  • T1-Weighted Images

    • Appears as a hypointense (dark) linear groove anterior to the precentral gyrus

    • Helps delineate the precentral gyrus (which appears as an isointense strip of cortex) from the anterior frontal gyri

  • T2-Weighted Images

    • Presents as a hyperintense (bright) CSF-filled sulcus

    • The precentral sulcus is seen as a well-defined linear space anterior to the central sulcus

  • FLAIR Sequence

    • Sulcus appears hypointense (dark) due to suppression of free CSF signal

    • Useful for detecting any abnormal signal within the sulcus (e.g., edema or inflammation), although in normal anatomy, the sulcus remains dark and well-defined

CT Appearance

  • Seen as a low-density (hypodense) linear groove on non-contrast CT, anterior to the more prominent central sulcus

  • Acts as an anatomical landmark for identifying the precentral gyrus, especially in trauma or infarct localization

  • May be more difficult to distinguish in elderly or in patients with brain atrophy, but typically remains identifiable in cross-section

MRI images

Precentral sulcus MRI 3T axial image

MRI images

Precentral sulcus MRI 3T sagittal image