decussation

[dee-kuh-sey-shuh n, dek-uh-]

noun

a process of becoming or condition of being crossed in the form of an X.
Anatomy. a nerve or tract of nerve fibers that crosses from one side of the central nervous system to the other.

Origin of decussation

First recorded in 1650–60; decussate + -ion

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

This arrangement is termed the decussation of the anterior columns of the medulla.
A Treatise on Physiology and Hygiene
Joseph Chrisman Hutchison
The most anterior is the pyramid or motor tract, the decussation of which has been seen.
Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 4
Various
Physicians are not without the use of this decussation in several operations, in ligatures and union of dissolved continuities.
The Works of Sir Thomas Browne
Thomas Browne

decussation in Medicine

(dĕk′ə-sā′shən, dē′kə-)

A crossing in the shape of an X.
An X-shaped crossing, especially of homonymous nerves or bands of nerve fibers, connecting corresponding parts on opposite sides of the brain or spinal cord.