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inferior_frontal_gyrus

Inferior frontal gyrus

Gyrus of the frontal lobe.

It is labelled gyrus frontalis inferior, its Latin name.

Its superior border is the inferior frontal sulcus (which divides it from the gyrus frontalis medius).

Its inferior border the lateral fissure (which divides it from the gyrus temporalis superior), and its posterior border is the inferior precentral sulcus.

Above it is the middle frontal gyrus (the gyrus frontalis medius), behind it the precentral gyrus (the gyrus praecentralis).

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

The middle frontal gyrus is usually more sinous than the inferior frontal gyrus (IFG) or superior frontal gyrus (SFG).

Parts

Pars opercularis

Pars triangularis

Pars orbitalis

The bone flap has been removed and the dura mater has been opened as a flap pediculated towards the greater sphenoid wing previously roungered to improve parasellar visualization. Sylvian fissure, Inferior frontal gyrus, Superior temporal gyrus and Middle temporal gyrus are exposed. Three pars of parasylvian inferior frontal gyrus must be distinguished: pars orbitalis (pOr) in relation to the orbital roof; pars triangularis (pT) the widest area of sylvian fissure (good place for start opening of sylvian fissure); pars opercularis (pOp) where Broca’s Area is located.

Removal of glioma from the dominant side of the inferior frontal gyrus (IFG) is associated with a risk of permanent language dysfunction. While intraoperative cortical and subcortical electrical stimulations can be used for functional language mapping in an effort to reduce the risk of postoperative neurological impairment, the extent of resection is limited by the functional boundaries. Recent reports proposed that a two-stage surgical approach for low-grade glioma in eloquent areas could avoid permanent deficits via the functional plasticity that occurs between the two operations.

In a patient with World Health Organization (WHO) grade II oligoastrocytoma in the left IFG, in functional plasticity of language occurred in the interval between two consecutive surgeries. Intraoperative electrical stimulations suggested that a language area and related subcortical fiber crossed the pre-central sulcus during tumor progression owing to functional plasticity. In the present case, the authors integrated neurophysiological data into the intraoperative neuronavigation system. They also confirmed the peri-lesional shift of language area and related subcortical fiber on image findings. Consequently, the tumor was sub-totally removed with two separate resections. Permanent language disturbance did not occur, and this favorable outcome was attributed to functional plasticity. The present experience sustains the multistage approach for low-grade gliomas in the language area. A combination of intraoperative electrical stimulations and updated neuronavigation may facilitate the characterization of brain functional plasticity 1).

1)
Saito T, Muragaki Y, Miura I, Tamura M, Maruyama T, Nitta M, Kurisu K, Iseki H, Okada Y. Functional Plasticity of Language Confirmed with Intraoperative Electrical Stimulations and Updated Neuronavigation: Case Report of Low-Grade Glioma of the Left Inferior Frontal Gyrus. Neurol Med Chir (Tokyo). 2014 Feb 28. [Epub ahead of print] PubMed PMID: 24584281.
inferior_frontal_gyrus.txt · Last modified: 2016/05/27 22:27 (external edit)