Anterior View of Dissected Brainstem. The corticospinal tract descends in sequence through the cerebral peduncle, basis pons, and medullary pyramid.  At the medulla-spinal cord junction, the fibers undergo a partial decussation (pyramidal decussation), with the majority of fibers crossing over to form the spinal cord lateral corticospinal tract.  The vestibulocochlear nerve exits the brainstem laterally at the ponto-medullary junction. Medial to the vestibulocochlear nerve, the facial nerve exits the brainstem. Further medially still, the abducens nerve exits at the ponto-medullary junction. (Image courtesy of M Nunez)