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Posterior orbital sulcus

The posterior orbital sulcus is a short cortical groove on the orbital (inferior) surface of the frontal lobe, located posteromedially on that surface. It typically lies behind the anterior orbital sulcus and helps separate the medial orbital gyrus from the posterior parts

Location

  • On the orbital (inferior) surface of the frontal lobe

  • Positioned posterior to the anterior orbital sulcus

  • Helps separate the medial orbital gyrus from the more lateral/posterior orbital gyri

  • Best seen on inferior frontal axial or coronal slices through the orbitofrontal cortex

MRI T1-weighted appearance

  • Sulcus (CSF) = low signal (dark)

  • Surrounding cortex = intermediate/gray

  • Adjacent white matter = brighter than cortex

  • Appears as a narrow dark groove on the inferior frontal surface

MRI T2-weighted appearance

  • Sulcus CSF = high signal (bright)

  • Cortex and white matter = darker relative to CSF

  • Appears as a bright line/groove between orbital gyri

MRI FLAIR appearance

  • Free CSF in sulcus = suppressed (dark)

  • Cortex and white matter = usual FLAIR signal

  • Appears as a thin dark cleft on the inferior frontal surface

CT (non-contrast) appearance

  • Sulcus (CSF) = low attenuation (dark)

  • Cortex and white matter = higher attenuation than CSF

  • Seen as a fine hypodense groove on the inferior frontal surface

CT (post-contrast) appearance

  • CSF in sulcus = non-enhancing, hypodense

MRI image

MRI Posterior orbital sulcus axial anatomy image -img-00000-00000