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Anterior orbital gyrus

The anterior orbital gyrus is a key subdivision of the orbital surface of the frontal lobe, located on the inferior aspect of the cerebral hemisphere above the orbits. It forms part of the orbital gyri, which are separated by the orbital sulci into four main regions (anterior, medial, lateral, and posterior). The anterior orbital gyrus lies at the most front part of the orbital surface, playing roles in higher cognitive functions, emotional regulation, and integration of sensory information, especially relating to social and olfactory cues.

Synonyms:

  • Anterior orbital convolution

  • Pars anterior orbitalis

  • Frontoorbital gyrus (anterior part)

  • Gyrus orbitalis anterior

Arterial Supply:

  • Primarily by branches of the orbital branches of the anterior cerebral artery (ACA).

  • Additional supply from the orbitofrontal branches of the middle cerebral artery (MCA).

  • Minor contributions from small meningeal branches of the internal carotid artery.

Venous Drainage:

  • Drained by superior orbital veins into the superior sagittal sinus.

  • Also receives drainage via superficial middle cerebral veins and frontal cortical veins.

  • Minor venous return through the sphenoparietal sinus.

Function:

  • Involved in decision making, reward, and affect regulation.

  • Important in olfactory processing and linking sensory cues to emotional responses.

  • Plays a role in social cognition, judgment, and adaptation of behavior to changing situations.

MRI Appearance:

  • T1-weighted images:

    • Appears isointense to slightly hypointense compared to adjacent cortical gray matter.

    • Cortical ribbon can be delineated from underlying white matter.

  • T2-weighted images:

    • Shows as hyperintense cortical gray matter with clear distinction from subcortical white matter.

    • Sulci and gyral patterns are well-visualized.

  • FLAIR sequences:

    • Gray matter appears intermediate to slightly hyperintense compared to white matter.

    • Helps identify pathologies such as cortical dysplasia, gliosis, or edema within the gyrus.

CT Appearance:

  • Appears as isodense to slightly hypodense cortical gray matter relative to adjacent brain structures.

  • Gyral pattern may be difficult to distinguish without pathology; visible as part of the orbital surface of the frontal lobe.

  • No calcifications or distinct features in normal conditions.

MRI images

anterior orbital gyrus MRI 3T axial image

MRI images

anterior orbital gyrus MRI 3T sagittal image

CT image

Anterior orbital gyrus CT axial anatomy image -img-00001-00001