The aim of this doctoral thesis was to gain a better understanding of the sulcal pattern of the human orbitofrontal cortex and its relation to the underlying cytoarchitecture. The first study resolved the confusion associated with the orbitofrontal sulci by identifying, quantifying, and precisely localizing the various orbital sulci from fifty human magnetic resonance scans that were transformed into the standardized stereotaxic space of Talairach and Tournoux (1988). The second study compared the individual sulci and sulcal patterns of these fifty human brains with the brains of fifty adult rhesus monkeys. Having examined the orbitofrontal sulci in these two species, a nomenclature for the human orbitofrontal sulci was established which was based on comparable sulci in the less convoluted macaque monkey brain while trying to preserve many of the familiar labels associated with this region in the human brain. The final part of this thesis examined the orbitofrontal cytoarchitecture of 10 human adult cerebral hemispheres to determine if a correlation exists between the different orbital sulci and the borders of the architectonic subregions.