decussation of the pyramids

noun

variants or decussation of pyramids

anatomy

: pyramidal decussation

An acute right-sided corticospinal system lesion above the decussation of the pyramids or a left-sided lesion below the decussation but above the seventh dorsal cord segment will abolish the left abdominal reflexes.

—Robert T. Ross, How to Examine the Nervous System, 2006

Word History

First Known Use

1810, in the meaning defined above

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