Topics

Topic

design image
Longitudinal cerebral fissure

The longitudinal cerebral fissure (also known as the interhemispheric fissure) is a prominent anatomical groove on the superior aspect of the brain, dividing the two cerebral hemispheres. This deep cleft runs along the midline, extending from the frontal to the occipital poles, and houses the falx cerebri, a dural fold. The fissure plays a critical role in separating the hemispheres, allowing for their individual development and function, and serving as a landmark in neuroimaging and neurosurgery.

Synonyms:

  • Interhemispheric fissure

  • Longitudinal fissure

  • Medial longitudinal fissure

  • Cerebral longitudinal fissure

Function:

  • Separates the right and left cerebral hemispheres

  • Provides space for the falx cerebri (a dural reflection)

  • Allows passage of major blood vessels (arteries and veins)

  • Serves as a landmark in neuroimaging and neurosurgical procedures

Arterial Supply:

  • Primarily supplied by the anterior cerebral arteries (ACA), which run within the fissure

  • Branches of the ACA (including the pericallosal and callosomarginal arteries) supply the medial aspects of the frontal and parietal lobes adjacent to the fissure

Venous Drainage:

  • Drained mainly by the superior sagittal sinus, which runs within the attached margin of the falx cerebri

  • Smaller cerebral veins drain into the superior sagittal sinus from the medial surfaces of the hemispheres

  • The inferior sagittal sinus (within the lower free margin of the falx cerebri) also receives venous blood from nearby medial brain structures

MRI Appearance:

  • T1-weighted MRI:

    • The fissure appears as a linear, hypointense (dark) gap filled with CSF, running between the higher signal intensities of the cortical gray matter

    • The falx cerebri is seen as a thin, low signal intensity line within the fissure

  • T2-weighted MRI:

    • CSF within the fissure appears hyperintense (bright)

    • The falx cerebri is hypointense (dark), sharply outlining the fissure

  • FLAIR MRI:

    • The fissure is visible as a dark (hypointense) line, as the CSF signal is suppressed

    • The falx cerebri remains hypointense, providing contrast against the suppressed CSF

CT Appearance:

  • Appears as a linear, hypodense (dark) midline cleft due to the low attenuation of CSF

  • The falx cerebri may be visualized as a thin, hyperdense (bright) structure within the fissure, especially if calcified

  • Clearly separates the two cerebral hemispheres, serving as a key landmark for identifying midline shift or space-occupying lesions

MRI images

Longitudinal cerebral fissure axial mri image

CT image

Longitudinal cerebral fissure CT