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Central sulcus of insula

The central sulcus of the insula is a prominent anatomical landmark found within the insular cortex of the human brain. It runs obliquely, dividing the insula into two main regions: the anterior short gyri and the posterior long gyri. The central sulcus of the insula plays a crucial role in defining the functional and anatomical organization of the insular cortex, which is deeply embedded within the lateral sulcus and covered by the frontal, parietal, and temporal opercula.

Synonyms

  • Central insular sulcus

  • Insular central sulcus

  • Sulcus centralis insulae

Function

  • Serves as a major anatomical boundary within the insula, dividing it into anterior and posterior lobules.

  • Helps delineate functional regions: the anterior insula is involved in emotion, cognition, and awareness, while the posterior insula is more involved in somatosensory and autonomic processes.

  • Important for surgical planning as a key landmark during insular resections or epilepsy surgery.

Arterial Supply

  • Mainly supplied by branches of the middle cerebral artery (MCA), especially the insular branches (also known as the insular arteries) originating from the M2 segment.

  • Additional small perforating arteries may arise from the MCA opercular branches.

Venous Drainage

  • Venous drainage primarily occurs via the deep middle cerebral vein (also called the Sylvian vein).

  • Smaller insular veins may drain into the superficial middle cerebral vein or other adjacent cortical veins.

MRI Appearance

  • T1-weighted MRI:

    • The central sulcus of the insula appears as a linear hypointense (dark) structure separating the anterior and posterior insular gyri.

    • Insular cortex and gyri appear isointense to surrounding cortex.

  • T2-weighted MRI:

    • The sulcus appears as a hyperintense (bright) linear structure due to the presence of cerebrospinal fluid (CSF) within the sulcus.

    • Gyri surrounding the sulcus are intermediate to hyperintense.

  • FLAIR MRI:

    • CSF within the central sulcus is typically hypointense (dark), allowing for clear delineation of the sulcus.

    • Adjacent insular gyri appear hyperintense in certain pathological conditions (e.g., edema, gliosis), otherwise isointense to cortex.

CT Appearance

  • On non-contrast CT, the central sulcus of the insula appears as a linear low-density (hypodense) structure due to the CSF within the sulcus.

  • The insular cortex itself appears isodense to the rest of the cortex; the sulcus is best visualized on thin slices or with multiplanar reformats.

MRI images

Circular sulcus of insula MRI 3T AXIAL IMAGE