Supramarginal

Supramarginal refers to a region of the brain, most commonly the supramarginal gyrus, which forms part of the inferior parietal lobule in the cerebral cortex. The term literally means “situated above the margin,” reflecting its position wrapping around the end of the Sylvian (lateral) fissure. In the left hemisphere, the supramarginal gyrus is typically identified as part of Brodmann area 40 and is closely linked with language-related networks; the right hemisphere version is more often associated with attention and spatial processing. The supramarginal gyrus lies above the lateral sulcus and is bordered by the angular gyrus posteriorly and adjacent language-related regions of the temporal and frontal lobes.

Functions attributed to the supramarginal gyrus include phonological processing, verbal working memory, and the perceptual integration of speech sounds with articulation. It participates in reading, speech repetition, and other language tasks, especially when phonological encoding or short-term memory for phonemes is required. On the right side, it contributes to attention, spatial orientation, and the integration of sensory information across modalities.

Clinical relevance centers on the consequences of damage or disruption to this region. Lesions in the left supramarginal gyrus can impair phonological processing and verbal working memory, affecting language tasks such as repetition and decoding. Functional imaging often shows SMG activation during language and phonological tasks, while right-hemisphere involvement appears in attentional and spatial contexts.

See also: angular gyrus, inferior parietal lobule, Wernicke’s area, arcuate fasciculus.