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Central sulcus

Anatomy

  • The central sulcus separates the frontal and parietal lobes.
  • The suclus runs from the paracentral lobule medially laterally to the subcentral gyrus.
  • The primary motor cortex sits anterior to the central sulcus.
  • The primary sensory cortex sits posterior to the central sulcus.

Identifying the central suclus

The central sulcus can be identified using a number of characteristic features described below. Where definitive localisation is required, for exmaple before resection of a tumour, fMRI and DTI can be used.

In the axial plane:

  • Omega sign: The hand motor knob, which has the shape of an inverted '' shape, projects into the central sulcus.
  • The superior frontal sulcus mets the pre-central sulcus, which is the sulcus anterior to the central suclus.
  • Bracket sign: the pars marginalis encompases the paracentral lobule. The central sulcus is the next anterior sulcus to the pars marginalis.
  • The post-central sulcus is slimmer than the post-central sulcus.
  • On gradient-echo or SWI, the primary motor cortex is lower signal than other cortex.

In the sagittal plane:

  • The pars marginalis of the cingulate sulcus curves upwards enclosing the paracentral lobule. The central sulcus it next sulcus anterior to the pars marginalis.
  • Hook sign: The hand motor knob, which projects into the central sulcus has a distintive 'hook' shape.
  • U sign: The 'U-shaped' subcentral gyrus wraps around the infero-lateral extent of the central sulcus.
  • M sign: The three components of the frontal operculum (a.k.a. inferior frontal gyrus) give an 'M-shape', which abut the inferior-lateral extent of the pre-central sulcus. The central sulus is the next posterior sulcus.