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Superior frontal gyrus

The superior frontal gyrus (SFG) is a prominent longitudinal convolution located on the superior and medial aspect of the frontal lobe. It forms part of the prefrontal cortex, extending from the frontal pole anteriorly to the precentral gyrus posteriorly. The SFG is divided into lateral and medial components by the superior frontal sulcus and includes parts of the supplementary motor area (SMA) and medial prefrontal cortex.

It plays a critical role in motor planning, working memory, decision-making, self-awareness, and voluntary movement control. Functionally, it is involved in higher cognitive processes and executive control networks, and lesions in this region can lead to deficits in attention, emotion regulation, and motor initiation.

Synonyms

  • Gyrus frontalis superior

  • Dorsomedial prefrontal cortex (medial portion)

Location and Structure

  • Anatomical position: The most superior gyrus of the frontal lobe, lying between the superior frontal sulcus (laterally) and the interhemispheric fissure (medially).

  • Boundaries:

    • Anteriorly: Frontal pole

    • Posteriorly: Precentral sulcus (separating it from precentral gyrus)

    • Inferiorly: Middle frontal gyrus

    • Medially: Cingulate sulcus and cingulate gyrus

  • Cortical composition: Contains both association and motor areas—Brodmann areas 6, 8, 9, 10, and 32.

Function

  • Cognitive control: Involved in reasoning, planning, decision-making, and sustained attention

  • Motor function: Medial portion forms the supplementary motor area controlling bilateral and complex motor sequences

  • Behavioral regulation: Linked with personality, mood, and social behavior

  • Self-awareness: Participates in introspective thought and executive functions

Clinical Significance

  • Lesions: May cause apathy, lack of motivation, and impaired judgment (“frontal lobe syndrome”)

  • Tumors and gliomas: Commonly low-grade gliomas, meningiomas, or metastases affecting the SFG

  • Ischemia: Involvement of the anterior cerebral artery territory causes contralateral leg weakness

  • Neurodegeneration: Affected early in frontotemporal dementia

  • Imaging importance: Site frequently evaluated in brain tumor grading, perfusion, and cortical mapping studies

MRI Appearance

T1-weighted images:

  • Cortex: Intermediate gray signal (gray matter)

  • White matter: Bright compared to cortex

  • Sulci and CSF: Dark (low signal)

  • Lesions:

    • Tumors appear as low-to-intermediate signal masses with cortical expansion

    • Infarcts show hypointensity with cortical thinning or volume loss

    • Hemorrhage (subacute) shows high signal intensity due to methemoglobin

T2-weighted images:

  • Cortex: Intermediate-to-bright signal

  • White matter: Darker than cortex

  • CSF: Very bright

  • Lesions:

    • Edema and gliosis: bright hyperintensity

    • Demyelination or infarction: hyperintense with poor gray-white differentiation

    • Chronic changes: gliotic cortical thickening with signal heterogeneity

FLAIR (Fluid-Attenuated Inversion Recovery):

  • Normal cortex: Intermediate gray signal

  • White matter: Slightly darker

  • CSF: Suppressed (dark)

  • Pathology:

    • Edema, gliosis, or demyelination: Bright hyperintense regions within the superior frontal gyrus

    • Cortical dysplasia or low-grade glioma: Subtle hyperintense thickening with indistinct cortical margins

    • Infarct or encephalomalacia: Mixed hyperintense and hypointense zones with sulcal enlargement

DWI (Diffusion-Weighted Imaging):

  • Normal cortex: Isointense to brain parenchyma

  • Acute infarction: Bright (restricted diffusion) with corresponding ADC hypointensity

  • Tumor necrosis or abscess: May show variable diffusion restriction depending on cellularity or pus content

  • Cytotoxic edema: Prominent restricted diffusion during acute ischemia

T1 Fat-Saturated Post-Contrast:

  • Normal cortex: Minimal enhancement

  • Enhancing lesions:

    • High-grade tumors or metastases: Intense heterogeneous enhancement with mass effect and surrounding edema

    • Meningioma: Uniform dural-based enhancement along convexity

    • Infective or inflammatory lesions: Patchy or ring enhancement with perilesional FLAIR hyperintensity

    • Post-surgical or radiation changes: Irregular enhancement along margins of resection cavity

CT Appearance

Non-Contrast CT:

  • Gray matter: Intermediate density, slightly denser than white matter

  • White matter: Lower attenuation

  • CSF spaces: Hypodense

  • Pathology:

    • Acute hemorrhage: Hyperdense area in the superior frontal region

    • Infarct: Hypodense cortical-subcortical area with loss of gray-white differentiation

    • Calcified lesions (oligodendroglioma, meningioma): Focal high-density deposits

    • Chronic infarct or atrophy: Cortical thinning and widened sulci

Post-Contrast CT:

  • Normal cortex: Minimal or no enhancement

  • Enhancing lesions:

    • Meningioma: Intense, homogeneous enhancement adjacent to inner table of skull

    • Metastasis or glioma: Irregular, ring, or nodular enhancement with surrounding hypodense edema

    • Infection or abscess: Peripheral rim enhancement with central low attenuation

    • Subacute infarct: May show mild gyral enhancement in reperfusion phase

MRI images

Superior frontal gyrus MRI 3T axial IMAGE

MRI images

Superior frontal gyrus MRI 3T SAGITTAL IMAGE

CT image

Superior frontal gyrus CT axial cross sectional anatomy radiology image