part of part of regional part of brain operculum of brain operculum The most posterior portion of the inferior frontal gyrus of the frontal lobe in the brain. In an axial plane, the Sylvian fissure extends from the operculum posteriorly to divide the frontal from the temporal lobe. Broca's area is a notable part of the operculum, which plays a key role in conversation or speech production, reading and writing. Its vascular supply comes from the M3 branches of the middle cerebral artery[WP]. UBERON:0010262 SCTID:362351003 Wikipedia:Operculum_(brain) frontal lobe