The process or point where two structures cross or intersect in an X shape, especially used in anatomy for nerve or fiber crossings.
From Latin decussatio, derived from decussare (to cross in X form). The -tion suffix creates a noun describing the action or result of crossing.
The optic chiasm is probably the most famous decussation in neuroscience—without this X-shaped crossing of your optic nerves, you couldn't see properly!
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