Pars marginalis

The marginal sulcus, also known as pars marginalis or ramus marginalis, is the extension of the cingulate sulcus posterosuperiorly, separating the paracentral lobule from the precuneus of the parietal lobe on the medial surface of the cerebral hemispheres.

Practical point

On axial images it appears as a short sulcus, reaching the apex but not extending laterally. It is an excellent landmark to help confirm the location of the central sulcus, which is located one sulcus anterior to the marginal sulcus, on the other side of the postcentral gyrus (bracket sign).