1
: the action of crossing (as of nerve fibers) especially in the form of an X
2
: a crossed tract of nerve fibers passing between centers on opposite sides of the nervous system

Word History

First Known Use

circa 1656, in the meaning defined at sense 1

Time Traveler
The first known use of decussation was circa 1656

Cite this Entry

“Decussation.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/decussation. Accessed 11 Mar. 2025.

Medical Definition

decussation

noun
1
: the action of intersecting or crossing (as of nerve fibers) especially in the form of an X see pyramidal decussation
2
a
: a band of nerve fibers that connects unlike centers on opposite sides of the nervous system
b
: a crossed tract of nerve fibers passing between centers on opposite sides of the central nervous system : commissure
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