Superolateral surface of brain
Reading File
Finding Sources
Finding Sources
Finding Sources
Finding Sources
Finding Sources
Finding Sources
Finding Sources
Finding Sources
Finding Sources
Searching the Web
superolateral surface of brain anatomy gyri sulci lobes
Reading File
Reading Web Page
https://www.ncbi.nlm.nih.gov/books/NBK575742
Reading Web Page
https://www.ncbi.nlm.nih.gov/books/NBK575742
Now I have sufficient information for a comprehensive answer. Let me compile it from both the textbook content and web sources.
Superolateral Surface of the Brain
The superolateral (dorsolateral) surface is the convex outer surface of the cerebral hemisphere that faces the inner table of the skull. It is separated from:
- The medial surface by the superomedial border (frontal to occipital pole)
- The inferior surface by the inferolateral border (part of which, anterior to the stem of the lateral sulcus, is called the superciliary border)
Key Primary Sulci (Constant Landmarks)
Four primary sulci divide the hemisphere into lobes. Two are prominent on the superolateral surface:
| Sulcus | Course | Significance |
|---|---|---|
| Lateral sulcus (of Sylvius) | Stem from inferior surface - branches into anterior horizontal, anterior ascending, and posterior branches on the lateral surface | Separates frontal/parietal lobe above from temporal lobe below |
| Central sulcus (of Rolando) | From superomedial border (1 cm behind midpoint of frontal-occipital poles) downward toward lateral sulcus | Separates primary motor cortex (precentral) anteriorly from primary somatosensory cortex (postcentral) posteriorly |
| Parieto-occipital sulcus | Mostly medial, but its upper end just notches onto the superolateral surface | Marks posterior boundary of parietal lobe |
Lobes on the Superolateral Surface
1. Frontal Lobe
Anterior to the central sulcus, above the lateral sulcus.
Sulci:
- Precentral sulcus - parallel and anterior to central sulcus
- Superior frontal sulcus
- Inferior frontal sulcus
Gyri:
| Gyrus | Location | Function |
|---|---|---|
| Precentral gyrus | Immediately anterior to central sulcus | Primary motor cortex (area 4) |
| Superior frontal gyrus | Above superior frontal sulcus | Supplementary motor area (medially) |
| Middle frontal gyrus | Between superior and inferior frontal sulci | Prefrontal association; eye fields (area 8) |
| Inferior frontal gyrus | Below inferior frontal sulcus; divided into pars orbitalis, pars triangularis, pars opercularis | Broca's area (pars opercularis + triangularis, area 44 & 45) in dominant hemisphere - motor speech |
2. Parietal Lobe
Posterior to central sulcus, above lateral sulcus, anterior to the occipital lobe.
Sulci:
- Postcentral sulcus
- Intraparietal (interparietal) sulcus - divides parietal lobe into superior and inferior parietal lobules
Gyri:
| Gyrus | Location | Function |
|---|---|---|
| Postcentral gyrus | Immediately posterior to central sulcus | Primary somatosensory cortex (areas 3, 1, 2) |
| Superior parietal lobule | Above intraparietal sulcus | Somatosensory association; spatial awareness |
| Inferior parietal lobule | Below intraparietal sulcus | Contains two important gyri: |
| - Supramarginal gyrus | Caps the upturned end of lateral sulcus | Part of Wernicke's area (area 40); reading/language |
| - Angular gyrus | Caps the superior temporal sulcus | Multimodal association; reading, writing (area 39) |
3. Temporal Lobe
Below the lateral sulcus, anterior to occipital lobe.
Sulci:
- Superior temporal sulcus
- Inferior temporal sulcus (often discontinuous)
Gyri:
| Gyrus | Location | Function |
|---|---|---|
| Superior temporal gyrus | Between lateral sulcus above and superior temporal sulcus below | Wernicke's area (posterior part, area 22) - auditory speech comprehension |
| Transverse temporal gyri of Heschl | On superior surface of superior temporal gyrus (within lateral sulcus) | Primary auditory cortex (areas 41 & 42) |
| Middle temporal gyrus | Between superior and inferior temporal sulci | Multimodal association |
| Inferior temporal gyrus | Below inferior temporal sulcus | Visual association |
4. Occipital Lobe
Posterior pole of the hemisphere. On the superolateral surface it is less well-demarcated (no constant sulcus separates it from the parietal lobe laterally - an imaginary line from the parieto-occipital sulcus to the pre-occipital notch marks the boundary).
Gyri: Variable - typically lateral occipital gyri (superior and inferior), involved in visual processing and object recognition.
Summary of Key Functional Areas on the Superolateral Surface
| Area | Location | Brodmann Area |
|---|---|---|
| Primary motor cortex | Precentral gyrus | Area 4 |
| Premotor cortex | Anterior to precentral gyrus | Area 6 |
| Frontal eye fields | Posterior middle frontal gyrus | Area 8 |
| Broca's speech area | Pars opercularis + triangularis of inferior frontal gyrus (dominant) | Areas 44, 45 |
| Primary somatosensory | Postcentral gyrus | Areas 3, 1, 2 |
| Primary auditory | Transverse temporal gyri (Heschl) | Areas 41, 42 |
| Wernicke's speech area | Posterior superior temporal gyrus (dominant) | Area 22 |
| Visual association | Lateral occipital gyri | Areas 18, 19 |
Clinical Correlations
- Broca's aphasia: lesion in pars opercularis/triangularis of dominant inferior frontal gyrus - non-fluent speech with intact comprehension
- Wernicke's aphasia: lesion in posterior superior temporal gyrus - fluent but meaningless speech, impaired comprehension
- Contralateral hemiplegia: precentral gyrus lesion (upper motor neuron)
- Contralateral hemisensory loss: postcentral gyrus lesion
- Gerstmann syndrome: angular gyrus lesion (dominant) - acalculia, agraphia, finger agnosia, left-right disorientation
- Neglect syndrome: inferior parietal lobule lesion (non-dominant) - hemispatial neglect
- Cortical deafness: bilateral Heschl's gyrus lesions
Sources: NCBI - Anatomy of the Cerebral Cortex; Kenhub - Gyri and Cerebral Cortex; Neuroscience: Exploring the Brain, 5th Edition
This is a shared conversation. Sign in to Orris to start your own chat.