CEREBRAL CIRCULATION AND

BRAINSTEM SYNDROMES

Presenter – Dr.GouthamModerator- Dr.SRIVANI MD

THE BRAIN

•Large mass of nervous tissue located in cranialcavity.•Has four major regions.

Cerebrum (Cerebral hemispheres)

Diencephalon: Thalamus, Hypothalamus, Subthalamus & Epithalamus

Cerebellum

Brainstem: Midbrain, Pons & Medulla oblongata

BLOOD SUPPLY OF BRAIN• Brain Receives 17% of cardiac output• Consumes 20% of entire Oxygen used by the

body• 10 seconds of interruption in blood flow leads to

unconsciousness• Most neurologic disorders are due to vascular

lesions

ANTERIOR AND POSTERIOR CIRCULATIONS• Anterior – Internal carotid arteries• Posterior – Vertebral arteries

ANTERIOR CIRCULATIONINTERNAL CAROTID artery Course it arises from the common carotid artery at the level of c4

vertebrae • Enters into Middle cranial fossa through carotid canal and

then enters through foramen lacerum into cavernous sinus Pierces dura and arachnoid maters.• It ends by Dividing into Anterior and Middle cerebral

arteries.

Branches of internal carotid artery1. Opthalmic artery

2. Posterior communicating artery

3. Anterior choroidal artery

4. Bifurcates into anterior cerebral artery and middle cerebral artery .

ANTERIOR CHOROIDAL ARTERY• Branch of internal carotid artery • Supplies posterior limb of internal capsule, retrolentiform and

sublentiform parts• Complete syndrome rare due to collaterals from MCA, PCA, and ICA• Syndrome comprises• c/l hemiplegia• c/l hemianaesthesia• c/l homonymous hemianopia

Anterior cerebral arterythe two anterior cerebral arteries joined together by anterior communicating artery.• Brain supplied by anterior cerebral artery Frontal poleMedial aspects of frontal and parietal lobes Basal gangliaCorpus callosum

Anterior Cerebral arteryA1 segment- proximal to anterior communicating artery it gives branches to anterior limb of internal capsule anteroinferior caudate anterior hypothalamus

A1 segment occlusion are rarely produces clinical syndrome because collateral flow through anterior communicating artery and collaterals from MCA and PCA

A2 SEGMENT• Part of anterior cerebral artery distal to anterior communicating

artery• supplies frontal pole , entire medial part of frontal and parietal lobe.

A2 SYNDROMELesion of A2 segment causes paralysis and sensory loss of C/L foot and

leg and involvement of paracentral lobule causes urinary incontinence.

MIDDLE CEREBRAL ARTERY • It arises from the internal carotid and continues into the later sulcus

where it then branches and projects to lateral cerebral cortex.

Middle cerebral ArteryM1 SEGMENT(proximal)-it gives deep penetrating or lenticulostriate branches which supplies Internal capsule, caudate nuclues, putamen and outer pallidus

M1 SYNDROME-occlusion of lenticulostriate branches-

Involvement of internal capsule produces contralateral hemiplegia.

Involvement of putamen, pallidus- leads to parkinsonian features.

Blood supply of internal capusle

Upper part ; lenticulo striate braches of MCALOWER PART : anterior chorodial artery

M2 Segment It has superior and inferior divisions supplies the entire superiolateral surface of cerebral hemispheres . Except• frontal pole• strip along the superiomedial frontal

and parietal cortex• medial temporal cortex• occipital lobe

M2 syndromes• If superior division involved• Brachial syndrome- weakness of hand and arm• Frontal opercular syndrome-Brocas aphasia with facial weakness with or without

arm weakness• proximal part of the superior division involved- clinical features of motor weakness,

sensory disturbances and brocas aphasia• If inferior division of M2 involved-• If dominant hemisphere- Wernickes aphasia without weakness with contralateral

homonymous superior quadrantanopia• If non dominant hemisphere- Hemispatial neglect , spatial agonosia without

weakness

Complete MCA syndrome• occulsion of both M1 AND M2 SEGEMENT IS COMPLETE MCA SYNDROME.

CLINICAL FEATURES • Contralateral hemiplegia• Contralateral hemianaesthesia• Contralateral homonymous hemianopia• If dominant hemisphere involved-Global aphasia• If non dominant hemisphere involved- Hemispatial neglect, and

constructional apraxia

CIRCLE OF WILLS o It is Formed by:

Two Anterior cerebral arteriesTwo Internal carotid arteriesTwo Posterior cerebral arteriesTwo Posterior communicating arteriesOne Anterior communicating artery

Branch of subclavian artery

• Structures Supplied by posterior circulation • Cerebellum• Medulla• Pons• Midbrain• Thalamus• Subthalamus• Hippocampus• Medial part of temporal lobe• Occipital lobe

Posterior cerebral artery

•P1 segment-proximal PCA supplies to - Midbrain, thalamus and subthalamus•P2 segment- distal PCA supplies to Temporal and occipital cortex.

P1 syndromes

•Due to the involvement of ipsilateral subthalamus, cerebral peduncles and midbrain

Posterior Cerebral Artery• P1 Syndromes

Syndrome Clinical features Localization

Claude’s syndrome 3rd nerve palsy contralateral ataxia

Rednucleus / cerebral peduncle

Weber’s syndrome 3rd nerve palsy hemiplegia Medial mid brain / cerebral peduncle

Benedikt’s syndrome 3rd Nerve palsy hemiplegiaAtaxia

Rednucleus / Medial mid brain

Subthalamic nucleus Contralateral hemiballismus

thalamic Déjerine-Roussy syndrome

contralateral hemisensory loss and agonizing pain

thalamus

P2 syndromes• ANTONS SYNDROME-bilateral occlusion in distal PCAs – bilateral

occipital lobe infarction- cortical blindness and patient often unaware and even deny it

• BALINTS SYNDROME-bilateral visual association areas- palinopsia and asimultagnosia

Blood supply of brain stem Structure Blood supply

Midbrain Posterior cerebral artery

Pons Basilar artery, superior cerebellar artery

Medulla Vertebral artery Posterior inferior cerebellar artery

Midbrain Syndromes

Syndrome Lesion location Structures involved Clinical features Comment

webers Midbrain base CN-3 fibers , cerebral peduncle

Ipsilateral 3-CN palsy,Contralateral hemiplegia

Usually vascular in origin

Claude’s Midbrain tegmentum

CN-3 fibers , red nucleus ,Superior cerebellar peduncle.

IpsilateraL 3-CN palsy,Rubral tremors,ContralateraL ataxia

Usually vascular in origin

Benedikt’s Midbrain tegmentum

CN-3 fibers , red nucleus ,Cerebral peduncle, Superior cerebellar peduncle

IpsilateraL 3-CN palsy, Rubral tremors,ContralateraL hemiplegia,Contralatera ataxia

Usually vascular in origin

Nothnagel’s Midbrain tectum(roof)

Ipsilateral OR BilateraL 3-CN, Superior cerebellar peduncle

3rd-CN palsy,Contralateral ataxia

Neoplastic in origin

Parineaud’s Midbrain dorsum Periaqueductal gray matter

Impaired upward gaze Usually due to mass lesion in the 3rd ventricle

Pontine syndromessyndrome Lesion

locationStructures involved Clinical features Comment

Millard-Gubler Pons Facial nerve nucleusCortico spinal tract

Ipsilateral facial nerve palsy,Contralateral hemiparesis

Usually vasucular

Foville’s Pons Facial nerve nucleusCortico spinal tractLateral gaze center

Ipsilateral facial nerve palsy,Contralateral hemiparesis,Horizontal gaze palsy.

Usually vasucular

Raymond’s Pons 6 th cranial nerve(abducence)Cortico spinal tract

Ipsilateral 6th nerve palsy,Contralateral hemiparesis,

Usually vasucular

Lateral medullary syndrome(Wallenburgs) Structure Clinical features

Spinothalamic tract Contralateral decreased pain and temperature

Spinocerebellar tract Ipsilateral ataxia

Sympathetic fibers Horners syndrome

Spinal trigeminal tract and nucleus(5th) Pain and numbness over Ipsilateral half of the face

Nucleus ambiguus Dysphagia,hoarseness

Vestibular nuclei Vertigo,nausea

Medial medullary syndromeStructure involved Clinical features

pyramid Contralateral hemiplegia

medial lemniscus contralateral loss of tactile and proprioception

hypoglossal nerve nucleus (12 th) Ipsilateral atrophy of half of tongue.

Thank u…