Human Brain's Calcarine Spur, Medial View

Description

Calcarine spur projects into the medial wall of the occipital horn of the lateral ventricle as a sharp inward ridge created by the overlying calcarine sulcus of the occipital lobe. Superior to the sulcus, the cuneus forms the dorsal bank; inferiorly, the lingual gyrus forms the ventral bank, with the spur marking their ventricular impression. From this fixed medial perspective, the spur sits posterior to the atrium (trigone) and posterior to the region where the choroid plexus typically extends, helping orient the viewer within the posterior ventricular system. A hard landmark. Because the calcarine sulcus overlies primary visual cortex (V1, Brodmann area 17), the calcarine spur becomes a practical internal reference when you need to translate surface neuroanatomy to deep ventricular relationships, including the territory implicated in posterior cerebral artery infarction with contralateral homonymous hemianopia and possible macular sparing. For neurosurgeons, the spur and adjacent occipital horn anatomy matter during intraventricular endoscopy, occipital horn catheter placement, and approaches traversing the atrium, where a few millimeters can separate an optimal trajectory from injury to optic radiations (Meyer loop more temporal, but posterior radiations crowd the periventricular occipital white matter). Crisp relief and controlled lighting make the ridge-to-sulcus relationship easy to teach without over-reliance on labels. Neuroanatomy and neuropsychology courses can pair this illustration with functional maps of the calcarine cortex to reinforce why occipital lesions produce specific visual field deficits. It also suits neurosurgical atlases and radiology teaching files as a reference point when correlating MRI of the occipital horn, periventricular leukomalacia patterns, or occipital horn enlargement in hydrocephalus. Anatomical accuracy verified by SciePro's Medical Advisory Board.