The term area 31 of Brodmann refers to a subdivision of the cytoarchitecturally defined cingulate region of cerebral cortex. In the human it occupies portions of the posterior cingulate gyrus and medial aspect of the parietal lobe. Approximate boundaries are the cingulate sulcus dorsally and the parieto-occipital sulcus caudally. It partially surrounds the splenial sulcus. Cytoarchitecturally it is bounded rostrally by the area 24 of Brodmann (human), ventrally by the area 23 of Brodmann (human), dorsally by the area 4 of Brodmann (human) and area 5 of Brodmann (human) and caudally by the area 7 of Brodmann (human) ( Brodmann-1909 ).