The lateral sulcus is the most prominent and deepest part of the cortical sulci, according to The Free Dictionary. The lateral sulcus extends from an anterior perforated type of substance.
The sulcus is made up of three portions that include a larger posterior ramus, which is more commonly known as the lateral sulcus. A shorter anterior ramus, which is found between pars triangularis and pars orbitalis and the shorter ascending ramus, is located between pars opercularis and pars triangularis. The synonyms of the sulcus lateralis include fissures of Sylvius, sylvian fissure, lateral cerebral fissure and fissure cerebi lateralis. This deep horizontal cleft marks a separation between the parietal lobes and the temporal lobes.