[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Head and neck](https://durgical.com/en/anatomy/region/head-and-neck/) › Lateral sulcus [Nervous system](https://durgical.com/en/anatomy/system/nervous-system/) · [Head and neck](https://durgical.com/en/anatomy/region/head-and-neck/) # Lateral sulcus The lateral sulcus is the deep groove on the side of the brain above the temporal lobe; the middle cerebral artery runs in it and the insula lies hidden inside. [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=head_neck&select=lateral_sulcus&side=r) Opens in the Durgical app, no sign-up needed. ## What it is The deep groove on the side of the brain above the temporal lobe. ## What it does The middle cerebral artery runs in it; the insula lies hidden inside. ## Key points - From its stem at the limen insulae it gives three rami: anterior horizontal and anterior ascending (both cutting into the inferior frontal gyrus) and the long posterior ramus, which turns up into the supramarginal gyrus - Its floor is the insula, hidden by the frontal, frontoparietal and temporal opercula; the middle cerebral artery runs on the insula (M2) and out over the opercula (M3) to the surface - Language cortex rings it on the dominant (usually left) side: Broca's area above its front, Wernicke's area behind and below, joined by the arcuate fasciculus; damage here impairs repetition - The [transverse temporal gyri](https://durgical.com/en/anatomy/transverse-temporal-gyri/) (Heschl gyri), the auditory cortex, lie on the hidden upper surface of the temporal lobe in its floor ## Key facts **Where** Sylvian fissure: deep cleft on the lateral surface of the hemisphere **Function** Separates the temporal lobe from the frontal and parietal lobes; insula in its depth; middle cerebral artery runs in it ## Relations **Above** Frontal and parietal opercula: pars opercularis and pars triangularis ([Broca's area](https://durgical.com/en/anatomy/opercular-part-of-inferior-frontal-gyrus/) on the dominant side), the lower ends of the [motor cortex](https://durgical.com/en/anatomy/precentral-gyrus/) and [sensory cortex](https://durgical.com/en/anatomy/postcentral-gyrus/), and the supramarginal gyrus **Below** [Superior temporal gyrus](https://durgical.com/en/anatomy/superior-temporal-gyrus/) of the [temporal lobe](https://durgical.com/en/anatomy/middle-temporal-gyrus/); on its hidden upper surface, Heschl gyrus and, behind it, the planum temporale **Deep** [Insula](https://durgical.com/en/anatomy/insula/), outlined by the circular sulcus; beneath it the extreme capsule, claustrum, external capsule and [putamen](https://durgical.com/en/anatomy/putamen/) **In front** Its stem lies along the lesser wing of the [sphenoid bone](https://durgical.com/en/anatomy/sphenoid-bone/) (sphenoid ridge), between the [frontal lobe](https://durgical.com/en/anatomy/superior-frontal-gyrus/) and temporal lobe, opening medially toward the anterior perforated substance **Contents** [Middle cerebral artery](https://durgical.com/en/anatomy/middle-cerebral-artery/) and its branches, the superficial middle cerebral (sylvian) vein draining toward the sphenoparietal or [cavernous sinus](https://durgical.com/en/anatomy/cavernous-sinus/), and CSF of the sylvian cistern ## How to find it The deepest, longest cleft of the lateral surface, running back and slightly up from the temple; its front part lies roughly deep to the [pterion](https://durgical.com/en/anatomy/pterion/). Scalp line: from about 3 cm behind the frontozygomatic suture, back almost parallel to the zygomatic arch. At surgery it is split along the superficial sylvian vein to expose the middle cerebral artery and the insula (transsylvian approach). ## On imaging On CT, blood in the sylvian fissure suggests a ruptured middle cerebral artery aneurysm; a bright dot in the fissure (dot sign) marks a clotted M2 branch. Wide sylvian fissures go with brain atrophy and, with tight sulci over the vertex, are typical of normal pressure hydrocephalus. ## Clinical notes - Middle cerebral artery aneurysms, usually at the main bifurcation, sit inside the fissure; rupture can cause a temporal lobe haematoma as well as subarachnoid blood - The transsylvian approach opens the fissure to reach aneurysms of the [circle of Willis](https://durgical.com/en/anatomy/cerebral-arterial-circle/), insular tumours and the region above the sella - Conduction aphasia: fluent speech and good comprehension with poor repetition, from damage to the arcuate fasciculus beneath the supramarginal gyrus at the back of the fissure - Congenital bilateral perisylvian syndrome: polymicrogyria around both fissures with weak face, [tongue](https://durgical.com/en/anatomy/tongue/) and throat movements (pseudobulbar palsy) and often epilepsy ## Anatomical variants - Usually asymmetric: the left fissure is longer and flatter and the right posterior ramus ends higher, matching the usually larger left planum temporale ## Development One of the first sulci to form in the fetus; the opercula then grow over the insula, which stays exposed in very preterm brains and in lissencephaly, where the fissures are shallow. ## Test yourself Think of the answer, then tap the question to see it. ## What lies in the depth of the lateral sulcus? The insula, hidden by the frontal, frontoparietal and temporal opercula. ## Which artery runs in the lateral sulcus? The middle cerebral artery: on the insula (M2) and out over the opercula (M3) to the surface. ## What does blood in the sylvian fissure on CT suggest? A ruptured middle cerebral artery aneurysm, usually at the main bifurcation; rupture can also cause a temporal lobe haematoma. ## Which language areas ring the lateral sulcus on the dominant side? Broca's area above its front and Wernicke's area behind and below, joined by the arcuate fasciculus; damage here impairs repetition. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anatomy/lateral-sulcus/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** sulcus lateralis TA2 5436 **Official Spanish (DeCS)** Surco lateral **English (TA2)** Lateral sulcus **Also called** Sylvian fissure · fissura Sylvii ## Related - [Middle cerebral artery](https://durgical.com/en/anatomy/middle-cerebral-artery/) Sources: Terminologia Anatomica (TA2); [Neuroanatomy, Sylvian Fissure](https://www.ncbi.nlm.nih.gov/books/NBK574552/); Tratado de anatomía humana (9.ª ed.), tomo II, Sistema nervioso central: cerebro, núcleos grises centrales, vías de conducción y circulación cerebral. ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/lateral-sulcus/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/lateral-sulcus/