The medulla is the longest portion of the brainstem, measuring approximately 3 cm in length (eFig. 9.32A). At the rostral connection of the medulla to the pons, it has a broad conical shape that tapers caudally before connecting with the spinal cord at the level of the foramen magnum. Along the midline of the anterior surface is the anterior median fissure, which continues on to the anterior surface of the spinal cord (eFig. 9.33B). Lateral to the fissure are the medullary pyramids composed of motor fibers descending from the cerebral cortex (eFig. 9.33B). Continuing caudally, the pyramids eventually give way to the decussation of the pyramids where the majority of motor fibers decussate to the opposing side. Lateral to the pyramids are the olives, which represent the underlying inferior olivary nuclei. It is at the junction of the pyramid and the olive that the rootlets of cranial nerve XII, the hypoglossal nerve, emerge (eFig. 9.33D). Oriented posterior to the olives are the inferior cerebellar peduncles, which form a connection between the cerebellum and medulla (eFig. 9.33D). At the junction of the olive and inferior cerebellar peduncles from rostral to caudal, rootlets of cranial nerves IX (glossopharyngeal), X (vagus), and XI (spinal accessory) emerge. Like the pons, the posterior surface of the medulla forms the floor of the fourth ventricle (eFig. 9.32A). Coursing down the midline of the posterior medulla is the posterior median sulcus, which continues into the spinal cord. On either side of the sulcus are the gracile and cuneate tubercles, formed by the underlying gracile nucleus and cuneate nuclei (eFig. 9.32A).