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Topic

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Medial orbital gyrus

The medial orbital gyrus is a prominent structure located on the inferior surface of the frontal lobe within the orbital part of the prefrontal cortex. It forms part of the orbital gyri complex, situated medially adjacent to the olfactory sulcus and separated laterally by the medial orbital sulcus from the other orbital gyri. This gyrus is essential for integrating sensory information and is involved in emotion, reward processing, and decision-making.

Synonyms

  • Medial orbital gyrus

  • Gyrus orbitalis medialis (Latin)

  • Medial orbital convolution

  • Medial orbital part of the frontal lobe

Arterial Supply

  • Primarily supplied by branches of the anterior cerebral artery (ACA), particularly the orbitofrontal artery (a branch of ACA)

  • May receive additional blood supply from small branches of the middle cerebral artery (MCA) (orbitofrontal branch)

  • The anterior communicating artery may provide minor collateral supply

Venous Drainage

  • Drained by small cortical veins that empty into the superior sagittal sinus and cavernous sinus

  • Drains via the superior orbital vein and anterior cerebral veins

  • Venous drainage pathways connect with the deep venous system of the brain

Function

  • Plays a crucial role in emotional processing and reward-related behaviors

  • Involved in decision-making and evaluation of risk versus reward

  • Integrates olfactory (smell) information with emotions and social behavior

  • Implicated in impulse control and aspects of personality

MRI Appearance

  • T1-weighted Images: Appears as gray matter, isointense to the cortex, with well-defined margins; adjacent sulci may be visible

  • T2-weighted Images: Hyperintense compared to white matter, with high water content typical of gray matter; sulci and gyri are well delineated

  • FLAIR (Fluid Attenuated Inversion Recovery): Gray matter remains hyperintense relative to white matter; helps to identify lesions (e.g., gliosis, infarcts) in the region

CT Appearance

  • Appears as isodense to other cortical gray matter

  • Boundaries may be less well defined compared to MRI, but medial location and relationship to the olfactory sulcus can aid identification

  • Pathological changes (such as infarcts or hemorrhage) are more easily seen as density changes or mass effect in this region

MRI images

medial orbital gyrus MRI 3T axial image

MRI images

medial orbital gyrus MRI 3T sagittal image

CT image

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