Brainstem stroke syndromes ppt

1. BRAINSTEM STROKE SYNDROMES

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. Located between the cerebrum and the spinal cord  Provides a pathway for tracts running between higher and lower neural centers. Consists of the midbrain, pons , and medulla oblongata . Brainstem Midbrain Pons Medulla obongata

4. Midbrain Pons Medulla oblongata Ventral surface of brain stem

5. Midbrain Cerebral peduncles Pons Basis pontis Medulla Ventral – Lateral View

6. Posterior circulation Vertebral artery branches   Posterior inferior cerebellar Medulla, lower cerebellum Basilar artery branches   Anterior inferior cerebellar Lower and middle pons , anterior cerebellum Superior cerebellar Upper pons , lower midbrain, upper cerebellum Posterior cerebral Medial occipital and temporal cortex and subjacent white matter, posterior corpus callosum , upper midbrain Thalamoperforate branches Thalamus Thalamogeniculate branches Thalamus

7. 8 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. MID-BRAIN STOKE SYNDROMES

9. Midbrain

10. Shortest brain stem,not more than 2cm in length,lies in the posterior cranial Fossa. For descriptive purpose,divided into Dorsal tectum and right and left cerebral Peduncles. Each cerebral peduncles divide further into ventral crus cerebri and a dorsal Tegmentum 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 3 rd and 4 th ventricles of the brain. Midbrain Crus cerebri

11. Basis pedunculi Substantia nigra Crus cerebri (cerebral peduncle) Cerebral aqueduct

12. Basis Tegmentum Tectum Ventral – Dorsal Organization

13. The roof of the aqueduct ( the tectum ) contains the corpora quadrigemina 2 superior colliculi that control reflex 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 colliculi larger and darker than inferior colliculi,the difference In colour due to superficial neurons in Superior colliculi Superior and inferior colliculi seperated by cruciform sulcus Superior colliculi Inferior colliculi

14. Internal structure Transverse section of midbrain Common 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. Medial midbrain syndrome ( paramedian branches 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. 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. Mid brain syndromes

18. Medial midbrain syndrome ( paramedian branches 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. Pontine syndromes

20. Pons

21. Pons The pons shows a convex anterior surface with prominent transversely running fibres . These fibres collect to form bundles,the middle cerebellar peduncles. The anterior surface of pons is marked in the midline by a shallow groove,the sulcus basilaris which lodges the basilar artery. Pons s Sulcus basilaris

22. Subdivided into ventral and dorsal part Ventral part of the pons contains Pontine nuclei: Recieves corticopontine fibres from frontal, temporal,parietal and occipital lobes of cerebrum The efferent fibres form the transverse fibres of pons . Vertically running corticospinal and corticopontine fibres . Transversely running fibres arising in pontine nuclei Pontine nuclei

23. The dorsal part of the pons may be regarded as continuation of the part of the medulla behind the pyramids. Superiorly continous with the tegmentum of the midbrain. Occupied predominately by reticular formation Posterior surface help to form floor of fourth ventricle The dorsal part is bounded laterally by inferior cerebellar peduncle in the lower part of the pons and superior cerebellar peduncle in upper part. Dorsal part of pons DORSAL PART Midpons Upper pons

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. 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. 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. 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. 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. Rt internuclear ophthalmoplegia

30. One and a half syndrome RT LT

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 (Horner's 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. MEDULLA OBLONGATA

33. 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 Posterior median fissure Medulla oblongata Most inferior region of the brain stem. Becomes the spinal cord at the level of the foramen magnum. External structure of medulla

34. Ventral surface of medulla oblongata contains Pyramid elevation between anterior median and anterolateral sulcus Formed due to decussation of corticospinal fibres . Pyramid Olive Olive Oval swelling between anterolateral posterolateral sulcus,half an inch long Produced by large mass of gray matter called inferior olivary nucleus External surface of medulla

35. Anterior median fissure Pyramid Anterolateral fissure Olive

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. 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 Horner's 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