Medulla Oblongata

Neuroanatomy

1. Welcome to Neuroanatomy presentation Presented by: Dr. Md. Saiduzzaman MD Resident(Phase B) Mymensingh Medical College Hospital.

2. Medulla Oblongata

3. Outline: Gross appearance of Medulla. Internal structures. Blood supply of medulla. Functions. Applied anatomy.

4. Gross appearance: The medulla oblongata connects the Pons superiorly and the spinal cord inferiorly. Conical in shape with the broad extremity directed upwards.

5. Cont…d Central canal of the spinal cord continues upward into the lower half of the medulla. Upper half of the medulla expands to contain the fourth ventricle.

6. Pyramid: Swelling on each side of anterior median fissure. Composed of bundles of nerve fibers, ( corticospinal fibers) originate from the precentral gyrus of the cerebral cortex. The pyramids taper inferiorly and majority of the descending fibers decussate to the opposite side.

7. Olive: Olives are the posterolateral oval elevations produced by the underlying inferior olivary nuclei. From the groove between the pyramid and the olive, the rootlets of the hypoglossal nerve emerge.

8. Internal structures: A. At the level of decussation of pyramids. B. At the level of decussation of lemnisci .

9. Medial lemnisci : The great sensory decussation . The lemnisci have been formed by the internal arcuate fibers, which emerge from the anterior aspects of the nucleus gracilis and nucleus cuneatus . The deussation takes place anterior to the central grey mater.

10. Fig: At the level of the middle of the olivary nuclei

11. Fig: superior part of the olivary nuclei just inferior to the pons .

12. Arterial supply: Medulla oblongata is supplied by the branches of vertebral, anterior and posterior spinal, posterior inferior cerebellar and basilar arteries.

13. Medulla Oblongata Arterial supply: Vertebral artery Anterior spinal artery PICA PICA Ant sp Vert

14. Venous drainage: The medulla oblongata is drained by veins that open into the spinal veins and neighboring venous sinuses.

15. Functions: 1. Connects the higher levels of the brain to the spinal cord. Responsible for regulating several basic functions of the autonomic nervous system which include: • Respiration – chemoreceptors . • Cardiac center – sympathetic and parasympathetic nervous system. • Vasomotor center- baroreceptors . • Reflex centers of vomiting, coughing, sneezing, and swallowing.

16. Applied Anatomy

17. Diseases of medulla oblongata Genetic Developmental Vascular Degenarative Inflammatory Infective Neoplastic

18. Genetic disease KENNEDY'S DISEASE (x-linked bulbospinal neuronopathy)

19. KENNEDY'S DISEASE (Characteristic features) Pathogenesis: x-linked recessive inheritance. Abnormal CAG expansion. Neurological menifestation: Slowly progressive limb-girdle muscular weakness. Early tremor. Slowly progressive bulbar dysfunction. Muscle cramps and fasciculation.

20. KENNEDY'S DISEASE (continued) Systemic menifestation: Gynaecomastia Endocrine abnormality . Diabetes insipidus. Laboratory characterestics: Abnormal sensory nerve conduction study. Abnormal sex hormone level. Genetic study.

21. DEVELOPEMENTAL Arnold-chiari malformation Syringobulbia

22. Chiari Malformation Types: Type-1 Type-2 Type-3 Type-4 Sign-symptoms: Hydrocephalus. Cranial nerve palsy Features of raised ICP Foramen – magnum syndrome

23. CHIARI MALFORMATION

24. Syringobulbia Presence of syrinx into medulla. Sign-symptoms: palatal and vocal cord palsy. Dysarthria. Nystagmus . Tongue weakness.

25. Vascular diseases: Lateral medullary syndrome. Medial medullary syndrome Opalski syndrome Babiniski-nageotte syndrome Avellis syndrome

26. Fig: Lateral Medullary Syndrome

27. Lateral medullary syndrome

28. Fig: Medial Medullary Syndrome .

29. Medial medullary syndrome

30. Opalski syndrome: Lateral medullary syndrome + ipsilateral hemiparesis . Corticospinal fibers involment caudal to pyramidal decussation .

31. Babinski-Nageotte syndrome Combined medial and lateral medullary syndrome. Also called Hemi- medullary syndrome.

32. Avellis Syndrome: 10th cranial nerve involvement + contralateral hemi-sensory loss.

33. Degenerative diseases: Motor Neuron Disease Progressive bulbar palsy Pseudobulbar palsy.

34. Differences between Bulbar and Pseudobulbar palsy

35. Infective diseases: Brainstem encephalitis (Viral, Bacterial, Fungal,Protozoal ) Lyme disease( Borellia ) Post-infectious (Bickerstaff encephalitis)

36. Bickerstaff encephalitis: • Following infection by CMV, Campylobacter jejeuni , Mycoplasma pneumonia. • criteria: External ophthalmoplegia . Ataxia. Lower limb areflexia . Extensor plantar response. Altered level of consciousness.

37. Cont…d • Differential diagnosis: > Miller-Fisher syndrome > ADEM. • Investigations: CSF analysis- increased protein. Anti-GQ1b IgG Antibody- may be present. Anti- Ganglioside Antibody MRI of brain- Hyperintense lesion in brainstem.

38. Inflammatory diseases: Bulbar GBS. Multiple sclerosis. CNS vasculitis .

39. Polyneuritis cranialis : Multiple cranial nerve palsy. Can occur in case of - Variant of GBS - TB meningitis. - Lyme disease - Lymphoma - Herpes simplex(type-2)

40. Neoplastic diseases: Glioma Glioblastoma multiforme Schwannoma Haemangioblastoma .