Glossary
Sulcus
What is a sulcus?
A sulcus is a groove or furrow on the brain's surface. The plural is sulci. The raised ridges between grooves are gyri. Together, these folds allow more cortical surface to fit inside the skull.
Major sulci of the brain
- Central sulcus: Separates the frontal and parietal lobes. The primary motor cortex lies in front of it, and the primary somatosensory cortex lies behind it.
- Lateral sulcus: Also called the Sylvian fissure, it separates the temporal lobe from the frontal and parietal lobes. The insular cortex lies deep within it.
- Calcarine sulcus: Lies in the occipital lobe, with primary visual cortex mainly along its banks.
Why it matters
Sulci are landmarks used to describe brain anatomy and interpret images. A visible fold is useful for orientation, but it does not mark every functional boundary exactly.