The posterior median sulcus of medulla oblongata (or posterior median fissure or dorsal median sulcus ) is a narrow groove; and exists only in the closed part of the medulla oblongata ; it becomes gradually shallower from below upward, and finally ends about the middle of the medulla oblongata, where the central canal expands into the cavity of the fourth ventricle .
Brain : rhombencephalon (hindbrain)
Metencephalon /pons
surface: Locus ceruleus
Trigeminal lemniscus (Dorsal trigeminal tract , Ventral trigeminal tract )
cranial nuclei :GSA : Principal V /Spinal V - VIII-c (Dorsal , Anterior )/VIII-v (Lateral , Superior , Medial , Inferior ) - SVE : Motor V - VII - GSE : VI - GVE : VII: Superior salivary nucleus
MLF, III, IV and VI (vestibulo-oculomotor fibers , medial vestibulospinal tract )
sensory/ascending: Trapezoid body/VIII - Superior olivary nucleus
Inferior cerebellar peduncle (Vestibulocerebellar tract )
motor/descending: Apneustic center • Pneumotaxic center (Medial parabrachial nucleus ) - Lateral parabrachial nucleus
Middle cerebellar peduncles (Pontocerebellar fibers ) - Pontine nuclei motor/descending: Corticospinal tract - Corticobulbar tract - Corticopontine fibers
Raphe/reticular
Reticular formation (Caudal , Oral , Tegmental , Paramedian ) • Raphe nuclei (Median )
Myelencephalon /medulla
Dorsal
surface: Posterior median sulcus - Postero-lateral sulcus - Area postrema
cranial nuclei :GVA : VII,IX,X: Solitary /tract • SVA : Gustatory nucleus • GSE : XII • GVE : IX,X,XI: Ambiguus • SVE : X: Dorsal • IX: Inferior salivatory nucleus - MLF, III, IV and VI
sensory/ascending: Gracile nucleus • Cuneate nucleus (Accessory cuneate nucleus ) • Sensory decussation • Medial lemniscus
motor/descending: Dorsal respiratory group
Ventral
motor/descending: Ventral respiratory group - Pyramid (Motor decussation ) - Inferior olivary nucleus (Olivocerebellar tract , Rubro-olivary tract )surface: Anterior median fissure - Antero-lateral sulcus - Arcuate nucleus of medulla - Olivary body
Raphe/reticular
Reticular formation (Gigantocellular , Parvocellular , Ventral , Lateral , Paramedian ) • Raphe nuclei (Obscurus , Magnus , Pallidus )