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Genu of corpus callosum

The genu of the corpus callosum is the anterior, curved part of the corpus callosum, which is the largest white matter structure in the brain. It forms the bend between the rostrum and the body of the corpus callosum, connecting the left and right cerebral hemispheres and facilitating interhemispheric communication. Its structure and vascular supply are vital for normal brain function, and its appearance on imaging studies provides essential information for diagnosing a range of neurological conditions.

Anatomy of Genu of Corpus Callosum

  • The genu is the anterior bend of the corpus callosum, located just above the rostrum and anterior to the body.

  • It appears as a prominent C-shaped structure on midline sagittal brain images.

  • The fibers of the genu curve downward and backward, forming the forceps minor that project into the frontal lobes.

Function

  • Facilitates communication between the left and right frontal lobes.

  • Integrates cognitive and motor information from both cerebral hemispheres.

  • Plays a role in executive functions, decision-making, and voluntary motor control.

Arterial Supply

  • Primarily supplied by the pericallosal artery, a branch of the anterior cerebral artery (ACA).

  • Additional blood supply may come from the callosomarginal artery, another ACA branch.

  • The subcallosal and medial callosal arteries may contribute minor branches.

Venous Drainage

  • Drains mainly into the callosal and subependymal veins.

  • These veins ultimately drain into the internal cerebral veins.

  • Venous blood from the genu may also reach the superior sagittal sinus indirectly.

MRI Appearance

  • T1-weighted images:
    – The genu appears hyperintense (bright) relative to gray matter, as it is composed of tightly packed myelinated fibers (white matter).
    – Stands out as a bright band anterior to the frontal horns of the lateral ventricles.

  • T2-weighted images:
    – The genu appears hypointense (dark) compared to surrounding gray matter due to the high myelin content of white matter.
    – Less bright than CSF and cortical gray matter, seen as a dark band.

  • FLAIR images:
    – The genu is hypointense (dark) relative to gray matter, similar to its T2 appearance, as FLAIR is a modified T2 sequence with CSF signal suppressed.
    – Pathological changes such as demyelination or edema will cause the genu to appear hyperintense (bright) on FLAIR.

CT Appearance

  • Appears as a hypoattenuating (darker) band of white matter anterior to the frontal horns of the lateral ventricles.

  • The genu is less distinct on CT than on MRI due to limited soft tissue contrast.

  • Pathological changes (e.g., infarcts, demyelination) may present as areas of hypoattenuation or volume loss.

MRI images

Genu of corpus callosum mri 3t coronal image

MRI images

Genu of corpus callosum mri 3t sagittal image