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7/31/2019 Brain Blood Supply I

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Blood supply to the medulla:Blood to the medulla is supplied by a number of arteries.

Anterior spinal artery: The anterior spinal artery supplies the whole medial part of the medulla oblongata. A blockage(such as in a stroke) will injure the pyramidal tract, medial lemniscus, and the hypoglossal nucleus. This causes asyndrome called medial medullary syndrome.

Posterior inferior cerebellar artery (PICA): The posterior inferior cerebellar artery, a major branch of the vertebral artery,supplies the posterolateral part of the medulla, where the main sensory tracts run and synapse. (As the name implies, italso supplies some of the cerebellum.)

Direct branches of the vertebral artery: The vertebral artery supplies an area between the other two main arteries,including the nucleus solitarius and other sensory nuclei and fibers. Lateral medullary syndrome can be caused byocclusion of either the PICA or the vertebral arteries.

No AICA for Medulla

Blood supply to the cerebellum:Three arteries supply blood to the cerebellum (Fig. 7):

The superior cerebellar artery (SCA), Anterior inferior cerebellar artery (AICA), and Posterior inferior cerebellar artery (PICA)

Artery: Posterior inferior cerebellar artery

The three major arteries of the cerebellum: the SCA, AICA, and PICA. (Posterior inferior cerebellar artery is PICA.)

The SCA branches off the lateral portion of the basilar artery, just inferior to its bifurcation into the posterior cerebral artery. Here itwraps posteriorly around the pons (to which it also supplies blood) before reaching the cerebellum. The SCA supplies blood tomost of the cerebellar cortex, the cerebellar nuclei, and the middle and superior cerebellar peduncles.The AICA branches off the lateral portion of the basilar artery, just superior to the junction of the vertebral arteries. From its origin,it branches along the inferior portion of the pons at the cerebellopontine angle before reaching the cerebellum. This artery suppliesblood to the anterior portion of the inferior cerebellum, and to the facial (CN VII) and vestibulocochlear nerves (CN VIII).Obstruction of the AICA can cause paresis, paralysis, and loss of sensation in the face; it can also cause hearing impairment.Moreover, it could cause an infarct of the cerebellopontine angle. This could lead to hyperacusia (dysfunction of the stapediusmuscle, innervated by CN VII) and vertigo (wrong interpretation from the vestibular semi-circular canal's endolymph accelerationcaused by alteration of CN VIII).The PICA branches off the lateral portion of the vertebral arteries just inferior to their junction with the basilar artery. Beforereaching the inferior surface of the cerebellum, the PICA sends branches into the medulla, supplying blood to several cranial nervenuclei. In the cerebellum, the PICA supplies blood to the posterior inferior portion of the cerebellum, the inferior cerebellarpeduncle, the nucleus ambiguus, the vagus motor nucleus, the spinal trigeminal nucleus, the solitary nucleus, and the

vestibulocochlear nuclei.


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Posterior inferior cerebellar artery

The posterior inferior cerebellar artery (PICsupplies for the cerebellum, part of the brain.vertebral artery leads to Wallenberg syndro

CourseIt winds backward around the upper part ofover the inferior cerebellar peduncle to the uThe medial branch continues backward to thunder surface of the cerebellum, as far as its lsuperior cerebellar branches of the basilar artBranches from this artery supply the choroid

DiseasesInfarction of this artery due to thrombosis orWallenberg syndrome. Severe occlusion of this

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3. Anterior ChoroidalArtery

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5. Basilar artery : Artery6. Internal Carotid Artery : Supplies7. Middle Cerebral Artery : Partly su

), the largest branch of the vertebral artery, is one of tOcclusion of the posterior inferior cerebellar artery ore, also called lateral medullary syndrome.

the medulla oblongata, passing between the origins ofdersurface of the cerebellum, where it divides into twnotch between the two hemispheres of the cerebellu

ateral border, where it anastomoses with the anterior iery.plexus of the fourth ventricle.

a stroke leads to lateral medullary syndrome, also knoor vertebral arteries could lead to Horner's Syndrome

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hose pontine branches supply blood to the pons, alonthe Substantia Nigra and STN along with the Post. Cpplies a large proportion of the basal ganglia, supplie

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capsule, Broca's area, Wernicke's Area, Heschl's Gyrus and the Angular Gyrus8. PICA : Artery that is a branch off the vertebral artery, along with which it supplies the medulla

oblongata. It also supplies the cerebellum9. Posterior cerebral artery : Forms when the basilar artery splits in 2 in the upper pons, it supplies the midbrain, thalamus,

inferior temporal lobes, medial occipital lobes and the cerebellum10. Posterior

communicating Artery: Supplies the Substantia Nigra and STN along with the Internal Carotid Artery and the

thalamus along with the posterior cerebral artery11. Superior Cerebellar

Artery: Artery that allows blood from the upper pons and lower medulla to be shared. It also supplies

the cerebellum12. Vertebral artery : Artery which supplies the medulla, along with PICA

Cerebellum 3: Function, Blood Supply and Clinical Correlates1. Adiadochokinesia : inability to perform rapid successive movements

2. All cerebellar syndromes cause signs onwhich side?

: ipsilateral signs

3. Anterior lobe of cerebellum supplied by : superior cerebellar artery (SCA)4. Archicerebellum (midline, vermis) does

what motor function?: Equilibrium, Posture

5. Archicerebellum (midline, vermis) doeswhat non-motor function?

: Autonomic responses, Emotion, Sexuality, Affectively important memory

6. Cerebellar Hemisphere Syndrome signs are : Ataxia, Dysmetria, Dyssynergia, Adiadochokinesia, Tremor, volitional

(intentional, harder you try, more it shakes), Muscular hypotonia,Dysarthria, Nystagmus

7. Describe initiation of movement in thecerebellum

: 3.Initiation of movement is via the Deep cerebellar nuclei firesimultaneously with pyramidal cortical neurons prior to movement

8. Describe motor learning in the cerebellum : 2. Motor learning is via Increased firing of Purkinje cells during learning ofa new motor task

9. Describe sensory-motor integration in thecerebellum

: 4. Sensory-motor integration, in which the cerebellum is involved ingenerating the prediction of the sensory consequence of movement (e.g.Inhibition of self tickle response)

10. Dysarthria : slurred speech11. Dysmetria : inability to estimate range of movement (past pointing, i.e. on touch nose

then touch finger, they miss finger)12. Dyssynergia : uneven & jerky movement

13. Lateral hemisphere lesions cause ataxiawhere?

: limb ataxia

14. Midline Cerebellum syndrome, sometimescalled archicerebellar syndrome can resultfrom?

: medulloblastoma upon vermis

15. Midline lesions cause ataxia where? : trunk ataxia16. Much of what is understood about the

functions of the cerebellum has been inferredhow?

: after careful documentation of the effects of focal lesions in humanpatients, and through research on the effects of focal lesions in animals

17. Nystagmus : rhythmic, involuntary eye movements.18. Posterior lobe of cerebellum supplied by : posterior inferior cerebellar artery (PICA)19. Signs of midline cerebellum syndrome : Truncal Ataxia, Nystagmus20. Ventral part of anterior cerebellum, and

posteior lobes, also flocculurnodular lobesupplied by

: anterior inferior cerebellar artery (AICA)

21. What are the 3 main NON-MOTORFUNCTIONS of the cerebellum?

: A) Autonomic (respiration, intestinal motility, bladder tone, etc.), B)Behavior (mood), C) Cognition & Memory.

22. What are the 4 motor functions of thecerebellum?

: 1. Error Detection & correction of cortically-originating movement; 2.Motor learning 3. Initiation of movement movement; and 4. Sensory-motor integration

23. What funciton does the Posterior Lobeperform?

: Concerned with higher order functions, Cognition in hemispheres,Limbic function in vermis

24. What function does the Anterior Lobe do? : Mainly involved with motor control25. What function does the Floccularnodular lobe

handle?: Balance and eye movement

26. What motor function does the Neocerebellum(hemispheres) do?

: Coordination

27. What non-motor function does theNeocerebellum (hemispheres) do?

: Planning, Memory, Language, Learning


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REGIONAL ARTERIAL SUPPLY OF THE BRAIN

Brain stemThe medulla oblongatais supplied by the branches of the

Vertebral, Anterior and posterior spinal, Posterior inferior cerebellar and Basilar arteries,

(Which enter along the anterior median fissure and the posterior median sulcus. Vessels that supply the central substance enteralong the rootlets of the glossopharyngeal, vagus, accessory and hypoglossal nerves. There is an additional supply via a pial plexus

from the same main arteries.)

The pons is supplied by the Basilar artery and Anterior inferior and Superior cerebellar arteries.

Direct branches from the basilar artery enter the pons along the ventral medial groove (basilar sulcus). Other vessels enter alongthe trigeminal, abducens, facial and vestibulcochlear nerves and from the pial plexus.

The midbrain is supplied by the Posterior cerebral, Superior cerebellar and Basilar arteries.

The crura cerebri are supplied by vessels entering on their medial and lateral sides. The medial vessels enter the medial side of thecrus and also supply the superomedial part of the tegmentum, including the oculomotor nucleus, and lateral vessels supply thelateral part of the crus and the tegmentum. The colliculi are supplied by three vessels on each side from the posterior cerebral andsuperior cerebellar arteries. An additional supply to the crura, and the colliculi and their penduncles, comes from the posterolateralgroup of central branches of the posterior cerebral artery.

CerebellumThe cerebellum is supplied by the

Posterior inferior, Anterior inferior and Superior cerebellar arteries.

The cerebellar arteries form superficial anastomoses on the cortical surface. Anastomoses between deeper, subcortical, brancheshave been postulated.

The choroid plexus of the fourth ventricle is supplied by the posterior inferior cerebellar arteries.

brain blood supply i

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