Inferior frontal gyrus

Inferior frontal gyrus
Inferior frontal gyrus of the human brain, gyrus frontalis inferior.
Lateral surface of left cerebral hemisphere, viewed from the side.
Details
Part of	Frontal lobe
Components	Pars opercularis, Pars triangularis, Pars orbitalis
Artery	Middle cerebral
Identifiers
Latin	gyrus frontalis inferior
NeuroNames	hier-67
NeuroLex ID	Inferior frontal gyrus
TA	A14.1.09.113
FMA	61860
Anatomical terms of neuroanatomy []

The inferior frontal gyrus is a part of the frontal gyrus of the frontal lobe (the yellow area of the human brain image to the right). It is labelled gyrus frontalis inferior, its Latin name. In the yellow area, its superior border is the inferior frontal sulcus (which divides it from the gyrus frontalis medius in the yellow area), its inferior border the lateral fissure (which divides it from the gyrus temporalis superior in the green area), and its posterior border is the inferior precentral sulcus (in the yellow area). Above it is the middle frontal gyrus (the gyrus frontalis medius), behind it the precentral gyrus (the gyrus praecentralis), both gyri in the yellow area of the image.

The inferior frontal gyrus, like the medial frontal gyrus, middle frontal gyrus and the superior frontal gyrus, is more of a region of the frontal gyrus than a true gyrus.

The inferior frontal gyrus can be subdivided into the following macroanatomical structures, shown in yellow in the top image, just below the label gyrus frontalis inferior:

The inferior frontal gyrus includes the following cytoarchitectonic areas:

The cytoarchitectonic areas very roughly correspond to the following macroanatomic structures: Brodmann area 44 to Pars opercularis, Brodmann area 45 to Pars triangularis, and Brodmann area 47 to Pars orbitalis. Brodmann area 44 corresponds to Broca's area (sometimes Broca's area is taken to encompass Brodmann's areas 44 and 45) — for the dominant hemisphere of the brain.

The left posterior inferior frontal gyrus (pIFG) is a part of the articulatory network I involved in motor syllable programs. The articulatory network itself contains three cortical areas; the posterior inferior frontal gyrus, the premotor cortex, and the anterior insula. These systems are interrelated but each has specific independent functions in speech comprehension and production. This system acts mostly when the vocal tract opens and closes during syllable production. Considered a "controller" of the motor aspect of speech production, the pIFG does not directly interact with the vocal tract; instead, it acts indirectly through the motor cortex. The posterior inferior frontal gyrus, connected to Brodmann Area 44, codes motor programs for this system while the auditory cortex (via the Spt) houses a series of sensory targets. Together, these areas function as a sensory-motor loop for syllable information coding.