Medulla Oblongata - PDF

Prof. Dr. Selda Önderoğlu Near East University Faculty of Medicine Dept. Of Anatomy  Medulla Oblongata  The most inferior part of brain stem.  It is like the widening of spinal cord upwards.  surfaces of Medulla oblongata Anterior posterior  anterio...

Prof. Dr. Selda Önderoğlu Near East University Faculty of Medicine Dept. Of Anatomy  Medulla Oblongata  The most inferior part of brain stem.  It is like the widening of spinal cord upwards.  surfaces of Medulla oblongata Anterior posterior  anterior surface: external features (from midline laterally) -Ant. Median fissure -Pyramid -pyramidal Decussation -Anterolateral Sulcus exits:Hypoglossal N. -Olive -Retroolivary Sulcus Exits: Glossophryngeal N. vagus N. accessory N. olive  Posterolateral surface of Medulla oblongata  glossopharyngeal N.  Vagus N.  Accessory N.  Inferior cerebellar Peduncle  Inferior Cerebellar Peduncle connects medulla to cerebellum Contains fibers of:  post. Spinocerebellar Tract  Some fibers of ant. Spinocerebellar tr.  cuneocerebellar tr.  Olivocerebellar tr.  vestibulocerebellar tr.  fibers from cerebellum to vestibular&reticular nuclei  so, tracts from cerebellum to medulla or the opposite  Posterior surface of Medulla Oblangata is the lower triangle of rhomboid fossa(floor of 4th ventricle)  4th ventricle &Rhomboid Fossa  4th ventricle :Is the space bw. Medulla&pons- cerebellum.Filled with cerebrospinal fluid  Rhomboid fossa: floor of 4th ventricle shape:quadrangular  its Lower triangle is related to: medulla oblon gata  Upper triangle to: pons  inferior part of post. Surface of Medulla Oblongata-from midline laterally has  posterior median Sulcus  Tuberculum gracilis(medial)- Fasciculus gracilis  Tuberculum cuneatus (lateral)-Fasciculus cuneatus  Superior part of post. Surface of Medulla oblangata ( Rhomboid fossa’s lower triangle) From midline laterally has:  post. Median sulcus  Medial Eminence  Sulcus limitans  vestibular Area  Stria medullaris  Cranial nerves emerging from medulla oblongata  Last 4 cranial nn.  glossopharyngeal n. (9)  Vagus n. (10)  Accessory n. (11)  Hypoglossal n. (12) The nuclei of these nn are located at medulla level(internal structure) Cranial nerve Nuclei in brainstem(9-12)  Nuc. ambiguus  It is the The motor nucleus of 9-10-11th CN):  glossopharyngeal n.(CN9)+Vagus n.(CN10)+Cranial part of accessory nerve (CN11) the nuclei of those 3 nn. Unite and form the nucleus Ambiguus  Spinal tract and nucleus of Trigeminal nerve(CN V)  F: Related to pain and temperature sensation carried from head and neck regions.  Located at pons, medulla and upper 1-2 segments of spinal cord.  At medulla level it is located posterolaterally Skin innervation of the face: is by the trigeminal nerve’s 3 branches: ophthalmic,maxillary& mandibular nn. Solitary Tract Nucleus  Related to taste sensation  Facial(7th) and glossopharyngeal (9th) cranial nerves  Dorsal Nucleus of Vagus Nerve  Parasympathetic nucl.of vagus n.  Inferior Salivatory Nucleus  Salivation.  P-symp. Nucleus of glossopharyngeal n. (9th.cranial nerve)  Brain stem (Cranial nerves) Medulla oblongata Pons mesencephalon  Vestibular Nuclei  4 vestibular nuclei 1- superior 2- inferior 3-medial 4-lateral Medial&inferior are at medulla oblongata level  Reticular Nuclei at medulla level  Nuc. reticularis lateralis  Nuc. reticularis ventralis  Nuc. reticularis gigantocellularis  Nuc. reticularis parvocellullaris  Nuc. reticularis paramedianus  Nuclei raphes – Nn. raphes obscurus – N. raphes pallidus – N. raphes magnus  Internal structure of Medulla Oblongata (transverse section at lower levels) Pyramidal Decussation Fasciculus gracilis Fasciculus cuneatus  Transverse section at the level of pyramidal decussation  Nuc. cuneatus  Nuc. Gracilis  Spinal tract& nucleus of trigeminal nerve  Transverse section through the inferior level of olive  Cuneate nucleus  Accessorius cuneate nucleus  Nucleus gracilis  Spinal tract& nucleus of trigeminal nerve  lateral reticular Nucleus  Transv.Section through the level of inferior olivary complex principal olivary nuc. Nuc.olivarius accessorius posterior Nuc. olivarius accessorius med. accessory cuneate Nuc.  Transv.Section through upper levels of medulla  Medial vestibular nuc.  ınf. vestibular nuc.  Gigantocellullar reticular nuc.  Dorsal cochlear nuc.  inferior olivary nuc.  Pyramis  Vagus nerve  Transv. Section of medulla oblongata-level?  4th Ventricle  Cerebellar nuclei  inf. cerebellar Peduncle  Ventral& dorsal cochlear Nuc.  medial Lemniscus  Arcuate Nuc.