Decussation of the pyramids
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| Brain: Decussation of the pyramids | ||
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| Deep dissection of brain-stem. Lateral view. ("pyramidal tract" visible in red, and "pyramidal decussation" labeled at lower right.) | ||
| Latin | decussatio pyramidum | |
| Gray's | subject #192 870 | |
| NeuroNames | hier-796 | |
| Dorlands/Elsevier | d_04/12282126 | |
The two pyramids contain the motor fibers which 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 two-thirds or more of them leave the pyramids in successive bundles, and decussate in the anterior median fissure, forming what is termed the pyramidal decussation.
Having crossed the middle line, they pass down in the posterior part of the lateral funiculus as the lateral cerebrospinal fasciculus.
[edit] Additional images
 Diagrams of the medulla spinalis. |
 Medulla oblongata and pons. Anterior surface. |
 Decussation of pyramids. Scheme showing passage of various fasciculi from medulla spinalis to medulla oblongata. |
 Section of the medulla oblongata through the lower part of the decussation of the pyramids |
 Section of the medulla oblongata at the level of the decussation of the pyramids. |
 Superficial dissection of brain-stem. Ventral view. |
 The motor tract. |
[edit] External links
- Dictionary at eMedicine pyramidal+decussation
- Anatomy Atlases - Microscopic Anatomy, plate 17.326 - "Medula Oblongata"
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 As such, some of the information contained herein may be outdated.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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