Broca's area

Last revised by EH Y on 27 Jan 2024

Broca's area (Brodmann areas 44 and 45) is an area of the lateral frontal lobe in the dominant hemisphere concerned with the production of speech.

Broca's area is located in the posterior inferior frontal gyrus (pars opercularis (Brodmann area 44) and pars triangularis (Brodmann area 45)) of the dominant hemisphere, anterior to the anterior commissure line. It is anterior to the primary motor cortex on the precentral gyrus.

It is bounded anteriorly by the ascending ramus of the lateral (Sylvian) fissure and posteriorly by the precentral sulcus.

This language-eloquent area is most often located in the left hemisphere, also in left-handed individuals 4. However, right-hemispheric dominance may occur in roughly 4% of right-handed individuals and may be as high as 27% in extreme left-handers 5.

Maybe even more interestingly, there appears to be significant plasticity of organization in the brain regarding the shift of language-eloquent hemisphere 5. This has recently been demonstrated to occur in right-handed patients under experimental conditions with left-sided (virtually reversible) perisylvian lesions by functional MRI (fMRI) 3.

Additionally, some doubt has been cast on the role of Broca's area in long term speech production outcomes following damage to Broca's area, with other regions (e.g. anterior arcuate fasciculus) implicated as being as, if not more, important 7.

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Cases and figures

  • Figure 1: Broca and Wernicke areas
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  • Figure 2: inferior frontal gyrus
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  • Figure 2: dual stream language model (MRI)
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  • Case 1: infarct involving Broca area
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