Brainstem stroke syndromes ppt

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  • Edingerwestphal n is the parasympathetic nucleus of 3rd cranial nerve3,7,9,10 = pure parasympathetic cranial nerves
  • CRUS CEREBRI= BASIS PEDUNCULI
  • Brainstem stroke syndromes ppt

    1. 1. BRAINSTEM STROKE SYNDROMES
    2. 2. Discussion will contain• Basic neuro-anatomy of the brainstem from a clinician’s perspective• Details of the blood supply of the brainstem• Various syndromes caused by stroke involving the brainstem vessels• RULE OF FOUR = a very simple way to remember various brainstem lesions.• Clinical case examples
    3. 3. BrainstemLocated between the cerebrumand the spinal cord Midbrain Provides a pathway for tracts runningbetween higher and lower neural centers. PonsConsists of the midbrain, pons,and medulla oblongata. Medulla obongata
    4. 4. Ventral surface of brain stem Midbrain Pons Medulla oblongata
    5. 5. Ventral – Lateral ViewMidbrainCerebralpeduncles Pons Basis pontis Medulla
    6. 6. Posterior circulationVertebral artery branchesPosterior inferior cerebellar Medulla, lower cerebellumBasilar artery branchesAnterior inferior cerebellar Lower and middle pons, anterior cerebellumSuperior cerebellar Upper pons, lower midbrain, upper cerebellumPosterior cerebral Medial occipital and temporal cortex and subjacent white matter, posterior corpus callosum, upper midbrainThalamoperforate branches ThalamusThalamogeniculate branches Thalamus
    7. 7. • Brain stem arteries - anterior view 1. Posterior cerebral artery 2. Superior cerebellar artery 3. Pontine branches of the basilar artery 4. Anterior inferior cerebellar artery 5. Internal auditory artery 6. Vertebral artery 7. Posterior inferior cerebellar a. 8. Anterior spinal artery• 9. Basilar artery 8
    8. 8. MID-BRAIN STOKE SYNDROMES
    9. 9. Midbrain
    10. 10. Midbrain Crus cerebriShortest brain stem,not more than2cm in length,lies in the posterior cranialFossa.For descriptive purpose,divided intoDorsal tectum and right and left cerebralPeduncles.Each cerebral peduncles divide furtherinto ventral crus cerebri and a dorsalTegmentum by a pigmented lamina“ Substantia nigra” Cerebral peduncles contains: -Descending fibers that go to the cerebellum via the pons -Descending pyramidal tracts Running through the midbrain is the hollow cerebral aqueduct which connects the 3rd and 4th ventricles of the brain.
    11. 11. Cerebral aqueduct Substantia nigra Basis pedunculi Crus cerebri(cerebral peduncle)
    12. 12. Ventral – Dorsal Organization Tectum Basis Tegmentum
    13. 13. Superior colliculiThe roof of the aqueduct ( the tectum) Inferiorcontains the corpora quadrigemina 2 superior colliculi that control reflex colliculi movements of the eyes, head and neck in response to visual stimuli 2 inferior colliculi that control reflex movements of the head, neck, and trunk in response to auditory stimuli Corpora quadregemina Superior and inferior colliculi seperated by cruciform sulcus Superior colliculi larger and darker than inferior colliculi,the difference In colour due to superficial neurons in Superior colliculi
    14. 14. Internal structureTransverse section of midbrainCommon to both at inferior and superior colliculus:Crus cerebri (or basis pedunculi): - Consists of fibres descending from cerebral cortex. - Its medial one-sixth is occupied by coticopontine fibres from frontal lobe,lateral one-sixth fibres from temporal,occipital and parietal lobes,the intermediate two third by corticospinal and cortico- nuclear fibres.Substantia nigra : - Present immediately behind and medial to basis pedunculi. - It appears dark as neuron within it contain pigment. ( neuromelanin )
    15. 15. Medial midbrain syndrome (paramedianbranches of upper basilar and proximal posterior cerebral arteries) • ON SIDE OF LESION Eye "down and out" secondary to unopposed action of fourth and sixth cranial nerves, with dilated and unresponsive pupil: Third nerve fibers ON OPPOSITE SIDE • Paralysis of face, arm, and leg: Corticobulbar and corticospinal tract descending in crus cerebri
    16. 16. Lateral midbrain syndrome (syndrome of small penetrating arteries arising from posterior cerebral artery) On side of lesion • Eye "down and out" secondary to unopposed action of fourth and sixth cranial nerves, with dilated and unresponsive pupil: Third nerve fibers and/or third nerve nucleus On side opposite lesion • Hemiataxia, hyperkinesias, tremor: Red nucleus, dentatorubrothalamic pathway
    17. 17. Mid brain syndromes
    18. 18. Medial midbrain syndrome (paramedianbranches of upper basilar and proximal posterior cerebral arteries) • ON SIDE OF LESION Eye "down and out" secondary to unopposed action of fourth and sixth cranial nerves, with dilated and unresponsive pupil: Third nerve fibers ON OPPOSITE SIDE • Paralysis of face, arm, and leg: Corticobulbar and corticospinal tract descending in crus cerebri
    19. 19. Pontine syndromes
    20. 20. Pons
    21. 21. PonsThe pons shows a convex anterior surface with prominent transversely running fibres. These fibres collect to form bundles,the middle cerebellar peduncles. PonsThe anterior surface of pons is marked in the midline by a shallow groove,the sulcusbasilaris which lodges the basilar artery. s Sulcus basilaris
    22. 22. Subdivided into ventral and dorsal partVentral part of the pons containsPontine nuclei:•Recieves corticopontine fibres from frontal, temporal,parietal and occipital lobes ofcerebrum•The efferent fibres form the transverse fibres of pons. Pontine nucleiVertically running corticospinal andcorticopontine fibres.Transversely running fibres arising inpontine nuclei
    23. 23. Dorsal part of pons MidponsThe dorsal part of the pons may be regarded ascontinuation of the part of the medulla behind thepyramids.Superiorly continous with the tegmentum of themidbrain. DORSAL PARTOccupied predominately by reticular formationPosterior surface help to form floor of fourthventricleThe dorsal part is bounded laterally by inferiorcerebellar peduncle in the lower part of the ponsand superior cerebellar peduncle in upper part. Upper pons
    24. 24. Medial inferior pontine syndrome (occlusion of paramedian branch of basilar artery) On side of lesion • Paralysis of conjugate gaze to side of lesion (preservation of convergence): Center for conjugate lateral gaze(PPRF) • Nystagmus: Vestibular nucleus • Ataxia of limbs and gait: Likely middle cerebellar peduncle • Diplopia on lateral gaze: Abducens nerve On side opposite lesion • Paralysis of face, arm, and leg: Corticobulbar and corticospinal tract in lower pons • Impaired tactile and proprioceptive sense over one- half of the body: Medial lemniscus
    25. 25. Lateral inferior pontine syndrome (occlusion of anterior inferior cerebellar artery) • On side of lesion • Horizontal and vertical nystagmus, vertigo, nausea, vomiting, oscillopsia: Vestibular nerve or nucleus • Facial paralysis: Seventh nerve • Paralysis of conjugate gaze to side of lesion: Center for conjugate lateral gaze • Deafness, tinnitus: Auditory nerve or cochlear nucleus • Ataxia: Middle cerebellar peduncle and cerebellar hemisphere • Impaired sensation over face: Descending tract and nucleus fifth nerve • On side opposite lesion • Impaired pain and thermal sense over one-half the body (may include face): Spinothalamic tract
    26. 26. Medial midpontine syndrome (paramedian branch of midbasilar artery) • On side of lesion • Ataxia of limbs and gait (more prominent in bilateral involvement): Pontine nuclei • On side opposite lesion • Paralysis of face, arm, and leg: Corticobulbar and corticospinal tract • Variable impaired touch and proprioception when lesion extends posteriorly: Medial lemniscus
    27. 27. Lateral midpontine syndrome (short circumferential artery) On side of lesion • Ataxia of limbs: Middle cerebellar peduncle • Paralysis of muscles of mastication: Motor fibers or nucleus of fifth nerve • Impaired sensation over side of face: Sensory fibers or nucleus of fifth nerve On side opposite lesion • Impaired pain and thermal sense on limbs and trunk: Spinothalamic tract
    28. 28. Medial superior pontine syndrome (paramedian branches of upper basilar artery) On side of lesion • Cerebellar ataxia (probably): Superior and/or middle cerebellar peduncle • Internuclear ophthalmoplegia: Medial longitudinal fasciculus • Myoclonic syndrome, of palate, pharynx, vocal cords, respiratory apparatus, face, oculomotor apparatus, etc.: — central tegmental bundle. On side opposite lesion • Paralysis of face, arm, and leg: Corticobulbar and corticospinal tract • Rarely touch, vibration, and position are affected(arm>leg): Medial lemniscus
    29. 29. Rt internuclear ophthalmoplegia
    30. 30. One and a half syndrome RT LT
    31. 31. Lateral superior pontine syndrome (syndrome of superior cerebellar artery) On side of lesion • Ataxia of limbs and gait, falling to side of lesion: Middle and superior cerebellar peduncles, superior surface of cerebellum, dentate nucleus • Dizziness, nausea, vomiting; horizontal nystagmus: Vestibular nucleus • Paresis of conjugate gaze (ipsilateral): Pontine contralateral gaze • Miosis, ptosis, decreased sweating over face (Horners syndrome): Descending sympathetic fibers On side opposite lesion • Impaired pain and thermal sense on face, limbs, and trunk: Spinothalamic tract • Impaired touch, vibration, and position sense, more in leg than arm : Medial lemniscus (lateral portion)
    32. 32. MEDULLAOBLONGATA
    33. 33. External structure of medullaMost inferior region of the brain stem.Becomes the spinal cord at the level ofthe foramen magnum.Medulla is broad above ,joins with pons narrow below, continous with spinal cordLength is about 3cm, width is about 2cm at its upper endSurfaces shows series of fissuresAnterior median fissure Medulla oblongataPosterior median fissure
    34. 34. External surface of medullaVentral surface of medulla oblongata containsPyramid•elevation between anterior median and anterolateral sulcus•Formed due to decussation of corticospinal fibres. Olive •Oval swelling between anterolateral posterolateral sulcus,half an inch long •Produced by large mass of gray matter called inferior olivary nucleus Olive Pyramid
    35. 35. Pyramid OliveAnterolateral fissure Anterior median fissure
    36. 36. Medial medullary syndrome(occlusion of vertebral artery or of branch of vertebral or lower basilar artery) On side of lesion • Paralysis with atrophy of one-half half the tongue: Ipsilateral twelfth nerve On side opposite lesion • Paralysis of arm and leg, sparing face; impaired tactile and proprioceptive sense over one-half the body: Contralateral pyramidal tract and medial lemniscus
    37. 37. Lateral medullary syndrome(occlusion of any of five vessels may be responsible—vertebral, posterior inferior cerebellar, superior, middle, or inferior lateral medullary arteries) On side of lesion • Pain, numbness, impaired sensation over one- half the face: Descending tract and nucleus fifth nerve • Ataxia of limbs, falling to side of lesion: Uncertain—restiform body, cerebellar hemisphere, cerebellar fibers, spinocerebellar tract (?) • Nystagmus, diplopia, oscillopsia, vertigo, nausea, vomiting: Vestibular nucleus • Horners syndrome (miosis, ptosis, decreased sweating): Descending sympathetic tract • Dysphagia, hoarseness, paralysis of palate, paralysis of vocal cord, diminished gag reflex: Issuing fibers ninth and tenth nerves • Loss of taste: Nucleus and tractus solitarius • Numbness of ipsilateral arm, trunk, or leg: Cuneate and gracile nuclei • Weakness of lower face: Genuflected upper motor neuron fibers to ipsilateral facial nucleus On side opposite lesion • Impaired pain and thermal sense over half the body, sometimes face: Spinothalamic tract

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