[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/) › Occipital lobe [Nervous system](https://durgical.com/en/anatomy/system/nervous-system/) · [Head and neck](https://durgical.com/en/anatomy/region/head-and-neck/) # Occipital lobe The occipital lobe is the back part of each half of the brain, at the back of the head; it processes vision. Official name: Superior occipital gyri [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=head_neck&select=occipital_lobe&side=r) Opens in the Durgical app, no sign-up needed. ## What it is The back of each hemisphere. ## What it does Processes vision. ## Key points - [Posterior cerebral artery](https://durgical.com/en/anatomy/posterior-cerebral-artery/) stroke: contralateral homonymous hemianopia, often with macular sparing, as the occipital pole may also get [middle cerebral artery](https://durgical.com/en/anatomy/middle-cerebral-artery/) branches - Bilateral damage causes cortical blindness with normal pupillary light reflexes (the reflex leaves the pathway before the cortex); some people deny being blind (Anton syndrome) - Two outflow streams: dorsal to the parietal lobe (where things are, motion) and ventral to the temporal lobe (what they are: objects, faces, colour) - Occipital seizures begin with simple visual phenomena, such as flashes or coloured shapes in the opposite visual field ## Key facts **Where** Back of the hemisphere behind the parieto-occipital sulcus **Blood supply** PCA **Function** Vision ## Relations **In front** [Parietal lobe](https://durgical.com/en/anatomy/superior-parietal-lobule/) (parieto-occipital sulcus on the medial surface) and, below, the [temporal lobe](https://durgical.com/en/anatomy/middle-temporal-gyrus/) **Behind** [Occipital bone](https://durgical.com/en/anatomy/occipital-bone/); the [transverse sinus](https://durgical.com/en/anatomy/transverse-sinus/) runs along the tentorial attachment at its lower edge **Below** [Tentorium](https://durgical.com/en/anatomy/tentorium-cerebelli/), with the [cerebellum](https://durgical.com/en/anatomy/anterior-quadrangular-lobule/) beneath it **Medial** [Falx cerebri](https://durgical.com/en/anatomy/falx-cerebri/); on the medial surface the calcarine sulcus with the [visual cortex](https://durgical.com/en/anatomy/cuneus/), the cuneus above and the lingual gyrus below **Deep** Occipital horn of the [lateral ventricles](https://durgical.com/en/anatomy/lateral-ventricle/) and the end of the optic radiation ## How to find it The parieto-occipital sulcus on the medial surface is its clear front border; the calcarine sulcus runs forward from the occipital pole and joins it in a Y. Laterally there is no dividing sulcus, only a line to the preoccipital notch. From outside, the lobe lies above the level of the inion (external occipital protuberance), which overlies the [confluence of sinuses](https://durgical.com/en/anatomy/confluence-of-sinuses/). ## Examination - Confrontation visual fields, each quadrant of each eye: a matching (homonymous) defect on the same side in both eyes places the lesion behind the [optic chiasm](https://durgical.com/en/anatomy/optic-chiasm/) - Pupillary light reflex: preserved in cortical blindness; reduced when the eye, [optic nerve](https://durgical.com/en/anatomy/optic-nerve/) or chiasm is the cause ## On imaging Diffusion-weighted MRI shows a posterior cerebral artery infarct along the medial occipital lobe. Posterior reversible encephalopathy syndrome (with severe high blood pressure, eclampsia or some immunosuppressants) shows vasogenic oedema on FLAIR, mainly in the parieto-occipital [white matter](https://durgical.com/en/anatomy/white-matter-of-telencephalon/) and cortex of both sides. ## Common problems - Head injury and tumours here change personality, judgement and planning. - Front-lobe dementia changes behaviour first. ## How it is diagnosed Neurological and memory tests; CT or MRI. ## Treatment - Surgery for tumours when possible. - Rehabilitation and support. ## Clinical notes - Alexia without agraphia: a left posterior cerebral artery stroke that also takes the splenium of the [corpus callosum](https://durgical.com/en/anatomy/corpus-callosum/); the person can write but cannot read what was written - Visual migraine aura, a shimmering zigzag scotoma that spreads over minutes, is attributed to spreading depression across the occipital cortex ## Related conditions - [MELAS (mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes)](https://durgical.com/en/conditions/melas/) - [Dementia with Lewy bodies](https://durgical.com/en/conditions/dementia-with-lewy-bodies/) - [Sturge–Weber syndrome](https://durgical.com/en/conditions/sturge-weber-syndrome/) - [Hallucinogen and dissociative drug intoxication (LSD, PCP, ketamine)](https://durgical.com/en/conditions/hallucinogen-and-dissociative-drug-intoxication/) - [Epilepsy and seizures](https://durgical.com/en/conditions/epilepsy-and-seizures/) ## Test yourself Think of the answer, then tap the question to see it. ## What visual field defect does a posterior cerebral artery stroke of the occipital lobe cause? A contralateral homonymous hemianopia, often with macular sparing, as the occipital pole may also get middle cerebral artery branches. ## Why are pupillary light reflexes normal in cortical blindness? The reflex fibres leave the visual pathway before the cortex; some people with bilateral occipital damage deny being blind (Anton syndrome). ## What are the two visual outflow streams from the occipital lobe? Dorsal to the parietal lobe (where things are, motion) and ventral to the temporal lobe (what they are: objects, faces, colour). ## What causes alexia without agraphia? A left posterior cerebral artery stroke that also takes the splenium of the corpus callosum: the person can write but cannot read what was written. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anatomy/superior-occipital-gyri/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** gyri occipitales superiores TA2 5481 **Official Spanish (DeCS)** Lóbulo Occipital DeCS D009778 **English (TA2)** Superior occipital gyri ## Related - [Posterior cerebral artery](https://durgical.com/en/anatomy/posterior-cerebral-artery/) Sources: Terminologia Anatomica (TA2); [DeCS](https://decs.bvsalud.org/es/ths/resource/?id=9963); [Neuroanatomy, Occipital Lobe](https://www.ncbi.nlm.nih.gov/books/NBK544320/). ## **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/superior-occipital-gyri/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/superior-occipital-gyri/