Parietal (superior) optic radiation
Radiation & CN III · Inferior quadrantanopia
The superior fibres of the optic radiation carry the superior retina, and therefore the inferior contralateral visual quadrant, straight backwards through the retrolenticular part of the internal capsule and the parietal white matter to the upper bank of the calcarine sulcus (cuneus).
Traced from the start
- Temporal hemiretinaNasal hemiretinaMacula and papillomacular bundle
- Optic nerve (CN II)
- Optic tract
- Lateral geniculate nucleus
- Parietal (superior) optic radiation
Detail
- Carries
- Superior retinal quadrants, i.e. the inferior contralateral visual field
- Course
- Retrolenticular internal capsule, lateral to the atrium of the lateral ventricle, to the occipital lobe
- Terminates
- Cuneus, above the calcarine sulcus
- Blood supply
- Middle cerebral artery branches, with the posterior cerebral artery posteriorly
When it goes wrong
Parietal lobe lesion (superior-division MCA infarct, tumour)
Contralateral inferior homonymous quadrantanopia ('pie on the floor'), with cortical sensory loss, hemineglect if non-dominant or Gerstmann syndrome if dominant, and asymmetric optokinetic nystagmus
Lesion of the whole radiation in the deep temporoparietal white matter or internal capsule
Complete contralateral homonymous hemianopia, usually congruous, with no RAPD and no macular sparing
Practise this structure
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