Dissected Brainstem Demonstrating the Abducens Nucleus and Facial Nerve. This dorsolateral perspective of the dissected brainstem reveals the courses of the facial and abducens nerves. The spinal trigeminal tract descends posteriorly through the lateral pontine tegmentum, dorsolateral to the facial motor nucleus and abducens nerve, and continues into the medulla.  Further medially can be seen the central tegmental tract and close to midline the medial longitudinal fasciculus.  On the right side of the brainstem, the superior cerebellar peduncle runs in the dorsolateral wall of the fourth ventricle. (Image courtesy of AL Rhoton, Jr.)