decussation
Americannoun
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a process of becoming or condition of being crossed in the form of an X .
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Anatomy. a nerve or tract of nerve fibers that crosses from one side of the central nervous system to the other.
Etymology
Origin of decussation
Explanation
When two things cross and form the shape of an X, that's decussation. Nature has many examples of decussation, from patterns in leaves to nerve fibers in the human body. Decussation is a technical term for something that happens all the time in the natural world. In our brains, for example, there is a type of decussation where nerve fibers cross from one hemisphere to the other. Botanists describe the decussation of leaves on a plant when they cross each other in patterns that form right angles. The Latin source is decussis, "the figure or shape of ten," or in Roman numerals, X.
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
In the dorsal column system, this decussation takes place in the brain stem; in the spinothalamic pathway, it takes place in the spinal cord at the same spinal cord level at which the information entered.
From Textbooks • Jun. 19, 2013
The defining landmark of the medullary- spinal border is the pyramidal decussation, which is where most of the fibers in the corticospinal tract cross over to the opposite side of the brain.
From Textbooks • Jun. 19, 2013
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.
From Scientific American Supplement, No. 520, December 19, 1885 by Various
Scattered in the “reticular substance” of the medulla from the upper end of the fourth ventricle to the pyramidal decussation, they merit the collective designation of reticular ganglia.
From Degeneracy Its Causes, Signs and Results by Talbot, Eugene S.
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.
From 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 by Livingstone, R.W.
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
