Definition of decussation 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.

What is decussation in the nervous system?

when fibers cross from one side of a structure to the other. For example, motor fibers that travel in the corticospinal tract originate in the cerebral cortex and travel down to the body.

What is decussation of pyramid?

Medical Definition of pyramidal decussation : the crossing of the fibers of the corticospinal tracts from one side of the central nervous system to the other near the junction of the medulla and the spinal cord. — called also decussation of the pyramids.