Inferior frontal gyrus: anatomy, location and function

What it is

The inferior frontal gyrus is the lowest of the three frontal gyri on the lateral frontal lobe, and contains Broca's area on the dominant side.

Location

It lies below the inferior frontal sulcus and above the lateral sulcus, divided into orbital, triangular and opercular parts.

Function

In the language-dominant hemisphere, the triangular and opercular parts (Broca's area, Brodmann areas 44 and 45) are essential for speech production and grammar. It is also involved in response inhibition.

Body system

Nervous · paired (left and right)

FMA ID

FMA72658 (Foundational Model of Anatomy)

Key facts

• Usually the left hemisphere is dominant for language.
• Supplied by the superior division of the middle cerebral artery.

Clinical relevance

Damage to Broca's area and the surrounding cortex causes non-fluent (expressive) aphasia with relatively preserved comprehension; a lesion confined to Broca's area often gives milder, transient deficits.

The nearest named structures in the 3D model, measured from the centre of each part:

• Middle frontal gyrus · nervous
• Insula · nervous
• Superior frontal gyrus · nervous
• Putamen · nervous
• Sphenoid part of middle cerebral artery · cardiovascular
• Anterolateral central branch of middle cerebral artery · cardiovascular
• Globus pallidus · nervous
• White matter of cerebral hemisphere · nervous
• Internal capsule · nervous
• Caudate nucleus · nervous