Opercular part of inferior frontal gyrus
Pars opercularis gyri frontalis inferioris
The hindmost section of the inferior frontal gyrus, lying in front of the precentral gyrus and covering part of the insula.
At a glance
- English
- Opercular part of inferior frontal gyrus
- Latin (TA2)
- Pars opercularis gyri frontalis inferioris
- System
- Brain and spinal cord
- Region
- Head
- Side
- Paired, left and right
About the opercular part of inferior frontal gyrus
The inferior frontal gyrus is the lowest of the three horizontal gyri on the lateral surface of the frontal lobe. Two short limbs of the lateral sulcus cut into it from below and divide it into three parts. The ascending ramus runs up into the gyrus, and the anterior or horizontal ramus runs forwards into it. Behind the ascending ramus is the opercular part; between the two rami is the triangular part; and in front of and below the horizontal ramus is the orbital part.
The opercular part, or pars opercularis, is the posterior section. It is bounded behind by the inferior precentral sulcus and the lower end of the precentral gyrus, in front by the ascending ramus, and below by the lateral sulcus. As its name says, it forms part of the frontal operculum, the lid of cortex that overhangs and hides the insula.
Its cortex is of a distinct type and corresponds to Brodmann area 44. In the left hemisphere of most people, area 44 together with the triangular part (area 45) makes up Broca's area, the region concerned with producing speech and with grammar. Studies link the opercular part in particular with planning the movements of speech, with processing word endings and sentence structure, and with recognising tone of voice in the native language. It also takes part in imitation and in inhibiting responses.
Damage here, typically from a stroke in the territory of the upper division of the middle cerebral artery, produces an expressive aphasia: speech becomes slow, effortful and short of grammatical words, while understanding is relatively spared.
Function and supply
- Function
- Part of Broca's area in the dominant hemisphere; involved in planning speech movements, processing grammar and recognising tone of voice.
- Blood supply
- Branches of the superior division of the middle cerebral artery, especially the prefrontal (candelabra) branches.
Anthromica
See the opercular part of inferior frontal gyrus where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
