Here is the vertex of a normal brain. Note the regular pattern of gyri and sulci. A sulcus is the depth between one gyrus and the next. The thin meninges cover the surface, but have been stripped away over part of the central fronto-parietal region at the right to reveal more clearly the sulci. The central fissure is where the extension of the dura between the hemispheres, called the falx cerebri, would be.