Exploration of the brain from its lateral aspect

External sagittal stratum

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Image #14-2
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Exploration of the brain from its lateral aspect
External sagittal stratum
The dissection has been continued posteriorly to the occipital pole by the removal of cortex and association bundles including the posterior part of the superior longitudinal fasciculus. This exposes a massive system of fibers (the external sagittal stratum) running toward the occipital pole in the depths of the hemisphere. Many of these fibers interconnect thalamic and cortical centers and course in the retrolenticular and sublenticular parts of the internal capsule (e.g., posterior stalk of the thalamus, geniculocalcarine tract). Fibers of the visual radiation (geniculocalcarine tract) at first pass outward from the lateral geniculate body, in the sublenticular part of the internal capsule (14), then turn posteriorly. They apparently do not form any exaggerated forward loops as is sometimes depicted.
1 . Central sulcus (of Rolando)
2 . Frontal part internal capsule
3 . Lentiform nucleus
4 . Inferior occipitofrontal fasciculus (cut across)
5 . Uncinate fasciculus (cut across)
6 . Middle cerebral artery (cut off)
7 . Temporal pole
8 . Right parietal lobe
9 . Parieto-occipital fissure right
10 . Cuneus
11 . Superior longitudinal fasciculus (cut across)
12 . Calcarine fissure right
13 . External sagittal stratum
14 . Sublenticular part of internal capsule
15 . Cerebellum
16 . Spinal medulla