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Brain: Decussation of pyramids
Gray684
Deep dissection of brain-stem. Lateral view. ("pyramidal tract" visible in red, and "pyramidal decussation" labeled at lower right.)
[[Image:|250px|center|]]
Latin decussatio pyramidum
Gray's subject #192 870
Part of
Components
Artery
Vein
BrainInfo/UW hier-796
MeSH [1]

The two pyramids contain the motor fibers that pass from the brain to the medulla oblongata and medulla spinalis, corticobulbar and corticospinal fibers.

When these pyramidal fibers are traced downward, it is found that some three-fifths or more of them leave the pyramids in successive bundles, and decussate in the anterior median fissure of the medulla oblongata, forming what is termed the pyramidal decussation or motor decussation.

Having crossed the middle line, they pass down in the posterior part of the lateral funiculus as the lateral cerebrospinal fasciculus.

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This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.


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