At the cord-medulla junction, 85% of the cortical axons cross the midline and shift to the lateral funiculus of the cord. Here, the contralateral corticospinal tract (left) is forming while 15% of the descending motor fibers remain in a ventral pyramidal tract.

• At the cord-medulla junction, 85% of the cortical axons cross the midline and shift to the lateral funiculus of the cord. Here, the contralateral corticospinal tract (left) is forming while 15% of the descending motor fibers remain in a ventral pyramidal tract.