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Brain Stem Brain Stem Anterior View Anterior View Posterior View Posterior View Adducent 7 & 8 th 12 9,10,11 5 3 4 Facial collicul Striae Medullare

Brain Stem Anterior View Anterior View Posterior View Adducent 7 & 8 th 12 9,10,11 5 3 4 Facial colliculus Striae Medullare

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Brain StemBrain Stem

Anterior ViewAnterior View Posterior ViewPosterior View

Adducent7 & 8th

12

9,10,115

3

4

Facial colliculus

Striae Medullare

Medulla OblongataMedulla Oblongata Nuclei in the medulla are Nuclei in the medulla are

associated w/ autonomic associated w/ autonomic control, cranial nerves, and control, cranial nerves, and motor/sensory relay.motor/sensory relay.

Autonomic nuclei:Autonomic nuclei: Cardiovascular centersCardiovascular centers

Cardioinhibitory/cardioacceleratory Cardioinhibitory/cardioacceleratory centers alter the rate and force of centers alter the rate and force of cardiac contractionscardiac contractions

Vasomotor center alters the tone Vasomotor center alters the tone of vascular smooth muscleof vascular smooth muscle

Respiratory rhythmicity centersRespiratory rhythmicity centers Receive input from the ponsReceive input from the pons

Additional CentersAdditional Centers Emesis, deglutition, coughing, Emesis, deglutition, coughing,

hiccupping, and sneezinghiccupping, and sneezing

Medulla….Medulla….

Medulla Sagittal Section And Medulla Sagittal Section And Cranial Nuclei Cranial Nuclei

Cranial NucleiCranial Nuclei

Section of Medulla Section of Medulla

Section of Medulla At the level Section of Medulla At the level of Pyramidof Pyramid

Medullary syndromesMedullary syndromes

MedialMedial Lateral medullary syndromesLateral medullary syndromes

Medial Medullary SyndromeMedial Medullary Syndrome

Cranial NervesCranial Nerves Tongue Paralysis -Tongue Paralysis -

Hypoglossal NerveHypoglossal Nerve Motor PathwaysMotor Pathways

Contralateral Spastic Contralateral Spastic Paralysis -- Pyramids Paralysis -- Pyramids

Sensory PathwaysSensory Pathways Contralateral loss Contralateral loss

Fine Touch and Fine Touch and Proprioception -- Proprioception -- Medial LemniscusMedial Lemniscus

Alternating Alternating hemiplegiahemiplegia

HypoglossalHypoglossalPalsyPalsy

Lower Motor Lower Motor NeuronNeuron

SyndromeSyndrome

HypoglossalHypoglossalPalsyPalsy

Lower Motor Lower Motor NeuronNeuron

SyndromeSyndrome Deviation of Tongue to affected sideDeviation of Tongue to affected side

Atrophy of Tongue MusclesAtrophy of Tongue Muscles

Lateral medullary syndromeLateral medullary syndrome(Wallenberg's syndrome)(Wallenberg's syndrome)

This is the commonest of the brain This is the commonest of the brain stem strokes. Involvement of the stem strokes. Involvement of the spinothalamic tract results in spinothalamic tract results in contralateral loss of pain and contralateral loss of pain and temperature sensation below the temperature sensation below the neck. neck.

Involvement of the descending Involvement of the descending nucleus and tract of V results in loss nucleus and tract of V results in loss of pain and temperature sensation of pain and temperature sensation on the face ipsilateral to the lesion.on the face ipsilateral to the lesion.

Lateral medullary syndromeLateral medullary syndrome

Involvement of descending autonomic Involvement of descending autonomic fibers results in an ipsilateral Horner's fibers results in an ipsilateral Horner's syndrome (ptosis, meiosis, and syndrome (ptosis, meiosis, and anhidrosis). Involvement of the nucleus anhidrosis). Involvement of the nucleus ambiguus causes palatal weakness and ambiguus causes palatal weakness and dysphagia.dysphagia.

Involvement of the inferior cerebellar Involvement of the inferior cerebellar peduncle (restiform body) causes peduncle (restiform body) causes ipsilateral ataxia. ipsilateral ataxia.

Alternating hemianaesthesiaAlternating hemianaesthesia

Brain stem Anterior viewBrain stem Anterior view

Brain stem Posterior viewBrain stem Posterior view

Section of Pons at the level of Section of Pons at the level of Facial colliculusFacial colliculus

Section of pons at the level of Section of pons at the level of trigeminal nucleitrigeminal nuclei

Vestibular component of VIII Vestibular component of VIII NerveNerve

Cochlear component of VIII Cochlear component of VIII NerveNerve

Pontine syndromesPontine syndromesMedial pontine SyndromeMedial pontine Syndrome

Structures AssociatedStructures Associated CSTCST Medial lemniscusMedial lemniscus 6th nerve fibers6th nerve fibers 77thth nerve fibres nerve fibres

SignSign Contralateral spastic Contralateral spastic

hemiparesis of the bodyhemiparesis of the body Contralateral loss of Contralateral loss of

position and vibration of position and vibration of the bodythe body

Medial strabismusMedial strabismus Raymond's SyndromeRaymond's Syndrome

Alternating abducent Alternating abducent hemiplegiahemiplegia

Miller-gubler syndromeMiller-gubler syndrome Alternating Facial Alternating Facial

hemiplegia.hemiplegia.

Lateral pontine syndromeLateral pontine syndrome

StructureStructure ICPICP Spinal 5Spinal 5 Spinothalamic Spinothalamic Fibers of 7Fibers of 7 Fibers of 8Fibers of 8

SignSign Ipsilateral limb ataxiaIpsilateral limb ataxia Ipsilateral pain and Ipsilateral pain and

temp loss - Facetemp loss - Face Contralateral pain and Contralateral pain and

temp-Bodytemp-Body Horner’s syndrome Horner’s syndrome

(Ipsilateral)(Ipsilateral) Hearing lossHearing loss Ipsilateral facial Ipsilateral facial

paralysisparalysis

Section of Mid Brain at Inferior Section of Mid Brain at Inferior colliculuscolliculus

Section of Mid Brain at superior Section of Mid Brain at superior colliculuscolliculus

At Superior colliculusAt Superior colliculus

Ventromedial Superior Midbrain Ventromedial Superior Midbrain SyndromeSyndrome

(Weber’s Syndrome)(Weber’s Syndrome) ContralateralContralateral

paralysis of face, arm and legparalysis of face, arm and leg IpsilateralIpsilateral

III palsy (fascicular)III palsy (fascicular) ArteryArtery

paramedian perforators of terminal basilar, paramedian perforators of terminal basilar, oror

peduncular perforating branches of peduncular perforating branches of posterior cerebral arteryposterior cerebral artery

Paracentral (Tegmental) Superior Paracentral (Tegmental) Superior Midbrain SyndromesMidbrain Syndromes

(Claude’s and Benedikt’s (Claude’s and Benedikt’s syndromes)syndromes)

ContralateralContralateral ataxia with tremor (red nucleus) ± ataxia with tremor (red nucleus) ±

hemichorea hemichorea (subthalamic nucleus)(subthalamic nucleus)

IpsilateralIpsilateral III fascicular palsyIII fascicular palsy

ArteryArtery paramedian perforators of terminal basilar, paramedian perforators of terminal basilar,

or or interpeduncular branches of Posterior interpeduncular branches of Posterior

Cerebral ArteryCerebral Artery

Dorsal Superior Midbrain Dorsal Superior Midbrain SyndromeSyndrome

(Parinaud’s, of Sylvian (Parinaud’s, of Sylvian Aqueduct)Aqueduct)

Paralysis of upgaze ± convergenceParalysis of upgaze ± convergence Light/near dissociationLight/near dissociation Eyelid retractionEyelid retraction Convergence/retraction nystagmusConvergence/retraction nystagmus ArteryArtery - posterior choroidal/quadrigeminal- posterior choroidal/quadrigeminal (Note - usually (Note - usually notnot vascular) vascular)

““Top of the Basilar” SyndromeTop of the Basilar” Syndrome

Usually due to embolic occlusionUsually due to embolic occlusion Posterior Cerebral Artery cortical territory Posterior Cerebral Artery cortical territory

infarction (unilateral or bilateral)infarction (unilateral or bilateral) hemianopia/cortical blindnesshemianopia/cortical blindness amnesiaamnesia

Basilar/Posterior Cerebral Artery Basilar/Posterior Cerebral Artery thalamic/midbrain territory infarctionthalamic/midbrain territory infarction impairment of ocular movements (e.g. skew impairment of ocular movements (e.g. skew

deviation, vertical gaze palsies)deviation, vertical gaze palsies) pupillary abnormalities (various)pupillary abnormalities (various)