44. T.S. Medulla -Open Part , At Level of Olive
"open part" (upper medulla) reveals the floor of the fourth ventricle with characteristic features like the median sulcus, hypoglossal and vagal triangles, vestibular area, and area postrema (a chemoreceptor zone). Internally, it shows nuclei for cranial nerves IX-XII, sensory tracts, and the inferior olivary nuclei, with the central canal expanding into the ventricle, contrasting with the "closed" lower medulla.