from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A crossing in the shape of an X.
- n. Anatomy An X-shaped crossing, especially of nerves or bands of nerve fibers, connecting corresponding parts on opposite sides of the brain or spinal cord.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A crossing or intersection of lines etc. so as to form an X-shape.
from the GNU version of the Collaborative International Dictionary of English
- n. Act of crossing at an acute angle, or state of being thus crossed; an intersection in the form of an X
from The Century Dictionary and Cyclopedia
- n. The act of crossing or intersecting; an intersection; the crossing of two lines, rays, fibers of nerves, etc.
- n. The state of being decussated, or that which decussates; a chiasm.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. an intersection or crossing of two tracts in the form of the letter X
He described the decussation of the optic nerves and the capsule of the crystalline lens, and gave the first clear description that has survived of the structure of the eye.
The Legacy of Greece Essays By: Gilbert Murray, W. R. Inge, J. Burnet, Sir T. L. Heath, D'arcy W. Thompson, Charles Singer, R. W. Livingston, A. Toynbee, A. E. Zimmern, Percy Gardner, Sir Reginald Blomfield
Prof. Hamilton, of Aberdeen, claims that the corpus callosum is not a commissure, but the decussation of cortical fibers on their way down to enter the internal and external capsules of the opposite side.
The red arrow, a, a, indicates the course the lateral cerebrospinal fasciculus takes at the level of the decussation of the pyramids; the blue arrow, b, b, indicates the course which the sensory fibers take.
Section of the medulla oblongata through the lower part of the decussation of the pyramids.
Transverse section passing through the sensory decussation.
The fibers converge toward the angle of the mouth, where the central fibers intersect each other, those from below being continuous with the upper segment of the Orbicularis oris, and those from above with the lower segment; the upper and lower fibers are continued forward into the corresponding lip without decussation.
The uppermost and lowermost fibers of the Buccinator pass across the lips from side to side without decussation.
The decussation of these sensory fibers is situated above that of the motor fibers, and is named the decussation of the lemniscus or sensory decussation.
Its lower part is interrupted by bundles of fibers which cross obliquely from one side to the other, and constitute the pyramidal decussation.
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.