2. CONTENT:-
1) Carotid system
2) vertebrobasilar system
3) Circle of Willis
4) Blood supply of midbrain
5) Blood supply of pons
6) Blood supply of medulla
7) Blood supply of cerebellum
8) Blood supply of thalamus
9) Blood supply of internal capsule
10) Blood supply of spinal cord
11) Anatomical variants
12) Clinical pearls
5. • The internal carotid arteries provide about 80%,
supplying most of the telencephalon and
much of the diencephalon.
• The vertebral system provides the remaining 20%,
supplying the brainstem and cerebellum as well as
parts of the diencephalon, spinal cord, occipital
and temporal lobes.
30. Circle of willis
• It is formed by the anterior and middle cerebral branches of internal
carotid and the posterior cerebral branches of basilar artery.
31.
32.
33. BRANCHES
• The branches of the circulus arteriosus are cortical and the central.
Cortical or external branches run on the surface of the cerebrum,
anastomose freely and if these get blocked they give rise to small
infarcts
• The central branches perforate the white matter to supply the
thalamus, the corpus striatum, and the internal capsule. These do not
anastomose and if these get blocked, they give rise to large infarcts.
34. The central branches are arranged in 4 groups:
• a. Anteromedial: The largest branch is called the medial striate or
recurrent artery of Heubner. It supplies corpus striatum and internal
capsule which has motor fibres for face, tongue and shoulder
• b. Anterolateral:These are in two groups. The largest branch is called
lenticulostriate or Charcot's artery of cerebral haemorrhage. It
supplies internal capsule which has motor fibres for one side of the
body.
35. • c. Posterolateral or thalamogeniculate: They supply thalamus and
geniculate bodies.
• d. Posteromedial supply thalamus and hypothalamus.
45. • Anterior limb-
1. Superior half- lateral lenticulostriate branch of MCA
2. Inferior half- recurrent artery of heubner of ACA
• genu-
1. Superior half- lenticulostriate branch of MCA
2. Inferior half- internal carotid artery
• Posterior limb-
1. Superior half- lenticulostriate branch of MCA
2. Inferior half- anterior choroidal artery of ICA
3. A part of posterior limb is also supplied by
posterior cerebral artery
• Sublentiform and retrolentiform nucleus- anterior choroidal artery
46. Blood supply of the Spinal Cord
• The spinal cord receives its arterial supply from three small arteries:
the 2 posterior spinal arteries and 1 anterior spinal artery.
74. Subclavian steal syndrome
• In a large study of extracranial arterial disease, the incidence of
subclavian/innominate stenosis/occlusion was 17 percent, but only
2.5 percent fulfilled the criteria for subclavian steal
• Classic subclavian steal — Subclavian artery occlusion or a
hemodynamically significant stenosis proximal to the origin of the
vertebral artery results in lower pressure in the distal subclavian
artery . As a result, blood flows from the contralateral vertebral artery
to the basilar artery and may flow in a retrograde direction down the
ipsilateral vertebral artery, away from the brainstem . Reversed
vertebral artery flow, although it may have deleterious neurologic
effects, serves as an important collateral artery for the arm in this
setting.
Fields WS et
al;JAMA,1972
79. Benedikt syndrome (medial midbrain
syndrome )
• Site- tegmentum of midbrain
• B. S.- upper basilar artery, posterior cerebral artery
• Clinical features
1. Ipsilateral 3rd cranial nerve palsy- down and out eyes, I/ l ptosis, loss of pupillary light reflex, dilated pupil
2. Red nucleus damage- C/ l tremor and ataxia, C/ l hemiballismus
3. Corticospinal tract- c/ l hemiparesis
80. Claude syndrome (lateral midbrain syndrome)
• Site- tegmentum of midbrain
• Blood supply - posterior cerebral artery
• Clinical features
1. Red nucleus injury- C/ l ataxia and tremor,c/ l hyperkinesia
2. I/ l 3rd cranial nerve palsy
81. Weber syndrome
• Site- lesion at crus cerebri
• Clinical features
1. I/ l 3rd cranial nerve palsy
2. Corticospinal tract - c/ l hemiplegia
82. Parinaud syndrome
• Site- midbrain dorsum tectum
• In one study of 206 patients, the etiology was hydrocephalus in 80 patients, stroke in 53,
and tumor in 45
• Clinical features
1. Impaired upgaze
2. Light near dissociation
3. Sun setting sign
4. Collier sign
5. Skew deviation of eyes
6. Convergence retraction nystagmus
Keane JR et al; Neurology, 1990
84. Nothnagel syndrome
• Site- lesion of roof of tectum and quadrigeminal plate
• Clinical features
1. I/ l LMN 3rd cranial nerve palsy
2. C/ l ataxia (d/ t superior cerebellar peduncle)
3. Features of parinaud syndrome (due to dorsal extension)
92. dejerine syndrome (medial medullary
syndrome)
• Blood supply- vertebral artery
• Clinical features -
1. Medial lemniscus- C/ l loss of proprioception
2. Hypoglossal nerve- I/ l tongue paralysis
3. Corticospinal tract- C/ l hemiparesis (face spared)
93.
94. Wallenberg syndrome (lateral medullary
syndrome)
• Blood supply- vertebral artery> pica
• Clinical features
1. Inferior cerebellar peduncle- I/ l ataxia
2. Vestibular nucleus- I/ l vertigo
3. Nucleus ambiguous- i/l bulbar paralysis, loss of gag reflex, dysphagia, hoarseness of voice
4. Nucleus tractus solitarius- I/ l loss of taste
5. Sympathetic tract- I/ l horner syndrome
6. Spinal nucleus- I/ l loss of pain and temperature from face
7. Spinothalamic tract – C/L loss of pain and temperature from body
8. Nucleus gracilis and cuneatus- I/ l numbness of arm ,trunk ,hand and leg
