About 80% to 90% of pyramidal or corticospinal tracts decussate in the pyramids of the medulla oblongata and descend as the lateral corticospinal tracts. Hence, they are known as “pyramidal tracts.” The uncrossed fibers decussate in the spinal cord, they form the anterior corticospinal tracts.
Due to this crossing over, the right hemisphere of the cerebrum controls the left side of the body and vice versa. Two exceptions of this crossing over are, olfactory system and somatic system, they project to the same side of the brain (ipsilateral projection).
Thus, the blanks can be filled with olfactory system; somatic system.