decussation of pyramids
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a crossing over; the intercrossing of fellow parts or structures in the form of an X.
decussation of pyramids the anterior part of the lower medulla oblongata in which most of the fibers of each pyramid intersect as they cross the midline and descend as the lateral corticospinal tracts.
de·cus·sa·tion of pyramids[TA]
the intercrossing of the bundles of corticospinal fibers at the lower border region of the medulla oblongata.