Last revised by Daniel J Bell on 23 Mar 2023

The operculum (plural: opercula) is the cortical structure which forms the lid over the insular cortex, overlapping it and covering it from external view. More specifically it consists of the cortical areas adjacent to the insular lobe and its surrounding circular sulcus.

The operculum can be divided into three portions:

  • the frontal operculum begins at the anterior ramus of the lateral fissure and extends to the inferior portions of the precentral gyrus, encompassing the pars triangularis and opercularis of the inferior frontal gyrus

  • the parietal operculum lies between the inferior portion of the postcentral gyrus and posterior rami of the lateral fissure. The frontal and parietal regions are often grouped together as the frontoparietal operculum

  • the temporal operculum is inferior to the lateral fissure itself and is formed by the superior temporal and transverse temporal (Heschl's) gyri

The function of the operculum depends primarily on the location of each of its segments. The frontal operculum rostral to the ascending ramus of the lateral fissure is associated with the prefrontal association cortex and plays a role in thought, cognition, and planning behavior. 

The frontoparietal operculum caudal to the ascending ramus is thought to contain the gustatory cortex and govern discrimination of various taste qualities. As this portion of the frontoparietal operculum contains inferior portions of the precentral (pars opercularis) and postcentral gyri, it also has a role in primary somatosensory and motor function.

The temporal operculum contains Heschl's gyrus which serves as the primary auditory complex. This is the termination of the afferent auditory pathway after having received fibers from the medial geniculate nucleus.

Operculum is the Latin word for lid or cover.

After the dissection of Albert Einstein's brain, there were claims that it was missing the parietal opercula bilaterally allowing his inferior parietal lobe to grow 15% wider than normal. It was thought that this could explain his great mathematical and scientific prowess. However, the debate regarding the legitimacy of these variations still continues.

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Figure 1: operculum
    Drag here to reorder.
  • Figure 2: Insula and operculum (annotated MRI)
    Drag here to reorder.