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Topic

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Olfactory sulcus

The olfactory sulcus is a prominent anatomical groove located on the inferior (orbital) surface of the frontal lobe of the brain. It is situated lateral to the gyrus rectus and medial to the orbital gyri, serving as a key landmark for the olfactory tract. The olfactory sulcus is essential for neurosurgical orientation, as its position relates closely to the olfactory bulb and tract, which are involved in the sense of smell. Its morphology and depth can also provide important clues in neuroimaging for developmental and neurodegenerative disorders.

Synonyms

  • Olfactory groove

  • Sulcus olfactorius

  • Olfactory fissure

Function

  • Acts as an anatomical landmark for the location of the olfactory bulb and tract.

  • Plays a crucial role in separating the gyrus rectus medially from the orbital gyri laterally.

  • Involved indirectly in the process of olfaction (smell perception) by housing the olfactory bulb and tract.

Arterial Supply

  • Supplied mainly by branches of the anterior cerebral artery (ACA), particularly the orbitofrontal branches.

  • Minor contributions from the anterior communicating artery may be present.

Venous Drainage

  • Drains into the superior sagittal sinus via the superficial cortical veins.

  • Additional drainage may occur through the anterior cerebral veins.

MRI Appearance

  • T1-weighted images: Appears as a linear hypointense (dark) groove on the inferior frontal lobe, lateral to the gyrus rectus.

  • T2-weighted images: Visualized as a linear hyperintense (bright) sulcus, better appreciated due to the high contrast between CSF (bright) and surrounding brain tissue (darker).

  • FLAIR: The sulcus appears hyperintense due to the CSF signal, but less bright compared to T2, as FLAIR suppresses pure CSF signal, providing enhanced delineation of adjacent lesions or pathology.

CT Appearance

  • The olfactory sulcus is visualized as a thin, linear, low-density groove along the inferior frontal lobe, though less conspicuous than on MRI.

  • Best seen in coronal and axial planes.

  • May become more prominent in cases of atrophy or developmental abnormalities.

MRI images

Olfactory sulcus MRI 3T axial image