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Straight gyrus

The straight gyrus, also known as the gyrus rectus, is a medial structure of the frontal lobe located on the inferior surface of the brain. It runs parallel and medial to the olfactory sulcus and is continuous anteriorly with the medial orbital gyrus. Though its precise function is not fully understood, the straight gyrus is thought to play a role in higher cognitive functions, emotion, and olfaction. It is clinically significant in neuroimaging and neurosurgery due to its proximity to important basal structures and midline pathologies.

Synonyms

  • Gyrus rectus

  • Medial orbitofrontal gyrus

  • Straight convolution

Arterial Supply

  • Mainly supplied by branches of the anterior cerebral artery (ACA), specifically the orbitofrontal branches.

  • Some contribution from the medial branches of the anterior communicating artery.

Venous Drainage

  • Drained by small cortical veins.

  • These veins typically empty into the superior sagittal sinus and, to a lesser extent, into the basal veins of Rosenthal.

Function

  • Involved in higher-order cognitive processes.

  • Plays a role in personality and emotional regulation.

  • Has connections to olfactory (smell) processing regions.

  • In some studies, associated with decision-making and social behavior.

MRI Appearance

  • T1-weighted imaging:

    • Slightly hypointense compared to white matter.

  • T2-weighted imaging:

    • Isointense to gray matter; similar signal to other cortical gray matter.

  • FLAIR imaging:

    • Similar signal characteristics to T2, except with fluid suppression (CSF appears dark).

CT Appearance

  • Appears slightly hyperintense (denser) compared to white matter.

  • Gray-white differentiation may be subtle but the straight gyrus stands out due to its medial, inferior location.

MRI images

Straight gyrus MRI 3T axial image

MRI images

Straight gyrus MRI 3T sagittal image

CT image

Straight gyrus CT axial cross sectional anatomy radiology image -img-00001-00001