1) The document discusses various syndromes that can result from lesions or occlusions in different parts of the posterior circulation arteries that supply the brainstem and cerebellum. 2) Specific syndromes are described based on the location of the lesion, including PCA, vertebral artery, and basilar artery syndromes. Onset, signs and symptoms on both sides of the lesion are outlined. 3) Midbrain, pontine, and medullary syndromes are also detailed. Bilateral lesions causing Anton's syndrome and Balint's syndrome are mentioned. A variety of resulting neurological deficits are associated with different posterior circulation artery occlusions.

1. DR.SARATH CHANDRA CHERUKURI
1st year PG in general medicine
KATURI MEDICAL COLLEGE

2.  Stroke or CVA is defined as abrupt onset of
neurologic deficit that is attributable to a
focal vascular cause.
 Stroke has occured if the neurologic signs
and symptoms last for >24 hours

3.  It is composed of the paired vertebral
artery,basilar artery&paired PCA’s
 These major arteries give rise to short&long
circumferential branches that supply the
cerebellum,medulla,pons,midbrain,thalamus,hipp
ocampus and medial temporal&occipital lobes
 PCA syndromes usually result from atheroma or
emboli at the top of basilar artery,fibromuscular
dysplasia or vertebral artery dissection

6.  P1 SYNDROME:infarction usually occurs in the
I/L subthalamus&medial thalamus and in I/L
cerebral peduncle&midbrain
 P2 SYNDROME:Cortical temporal and occipital
lobe signs

7.  The VERTEBRAL artery has 4 segments
V1,V2,V3&V4
 The fourth segment courses upward to join
the other vertebral artery to form the basilar
artery
 Only V4 gives rise to branches that supply the
brainstem&cerebellum
 The PICA,in its proximal segment supplies the
lateral medulla and in its distal branches the
inferior surface of cerebellum

9.  ON SIDE OF LESION:
1) Pain,numbness,impaired sensation over
one-half of face:5th nerve nucleus
2) Ataxia:restiform body,cerebellar
hemisphere,spinocerebellar tract
3) Nystagmus,diplopia,vertigo,nausea,vomting
:vestibular nucleus
4) Horner’s syndrome:descending sympathetic
tract
5) Dysphagia,paralysis of palate,vocal
cord,diminished gag reflex:fibres of
9th&10th nerves

10. 6)Loss of taste:nucleus&tractus solitarius
7)Numbness of I/L arm,trunk&leg:
cuneate&gracile nucleus
8)Weakness of lower face:UMN fibres to I/L
facial nucleus
 ON SIDE OPPOSITE LESION:
1) Impaired pain&thermal sense over half the
body,sometimes face:Spinothalamic tract

11.  On the side of lesion:
1) Paralysis with atrophy of half the tongue:
I/L 12th nerve
 On the side opposite lesion:
1) Paralysis of arm&leg sparing face;impaired
tactile&proprioceptive sense over one half
of the body:C/L pyramidal tract&medial
leminiscus

12.  Branches of basilar artery supply the base of
the pons&superior cerebellum and fall into
3 groups:
1) Paramedian,7-10 in number supply a wedge
of pons on either side of midline
2) Short circumferential,5-7 that supply lateral
two-thirds of pons&middle,superior
cerebellar peduncle
3) B/L long circumferential(SCA&AICA) course
around pons to supply the cerebellar
hemispheres

14.  MEDIAL INFERIOR PONTINE SYNDROME:
 ON THE SAME SIDE:
1) Paralysis of conjugate gaze to the side of
lesion
2) Nystagmus:vestibular nucleus
3) Ataxia:middle cerebellar peduncle
4) Diplopia on lateral gaze:abducens nerve
 ON THE OPPOSITE SIDE:
1) Paralysis of face,arm&leg:CB&CS tracts
2) Impaired tactile&proproiceptive sense over
one-half of body:medial leminiscus

15.  LATERAL INFERIOR PONTINE (AICA)
SYNDROME:
 ON THE SIDE OF LESION:
1) Horizontal&vertical gaze
nystagmus,vertigo,nausea,vomting:vestibula
r nerve or nucleus
2) Facial paralysis:7th nerve
3) Ataxia:middle cerebellar
peduncle&cerebellar hemisphere
4) Impaired sensation over face:descending
tract&5th nucleus
 ON THE SIDE OPPOSITE LESION:
1) Impaired pain and thermal sense over one-
half of body

17.  ON THE SIDE OF LESION:
1) Ataxia of limbs and gait-pontine nucleii
 ON THE SIDE OPPOSITE LESION:
1) Paralysis of face,arm&leg:corticobulbar and
corticospinal tracts
2) Variable impaired touch and
proprioception:medial leminiscus

18.  ON THE SIDE OF LESION:
1) Ataxia:middle cerebellar peduncle
 Paralysis of muscles of mastication:motor
fibres or nucleus of 5th nerve
 ON THE SIDE OPPOSITE LESION:
1) Impaired pain and thermal sense on limbs
and trunk:spinothalamic tract

20.  MEDIAL SUPERIOR PONTINE SYNDROME:
 ON THE SIDE OF LESION:
1) Cerebellar ataxia:superior/middle cerebellar
peduncle
2) Internuclear ophthalmoplegia:MLF
3) Myoclonic syndrome,palate,pharynx,vocal
cords-dentate projection,inferior olivary
nucleus
 ON THE SIDE OPPOSITE LESION:
1) Paralysis of face,arm&leg:CB&CS tract
2) Rarely touch,vibration&position:medial
leminiscus

21.  LATERAL SUPERIOR PONTINE
SYNDROME OR SCA OR MILLS’
SYNDROME:
 ON SIDE OF LESION:
1) Ataxia:middle&superior cerebellar
peduncles,dentate nucleus
2) Dizziness,nausea,horizontal
nystagmus:Vestibular nucleus
3) Horner’s syndrome:descending sympathetic
tract
4) Tremor:red nucleus,superior cerebellar
peduncle

22.  ON SIDE OPPOSITE LESION:
1) Impaired pain&thermal sense on
face,limbs&trunk:spinothalamic tract
2) Impaired touch,vibration&position
sense:medial leminiscus

23.  MILLARD-GUBLER SYNDROME:I/L LMN type
facial nerve palsy&C/L hemiparesis due to
involvement of 7th nerve nucleus&CST
 FOVILLE’S SYNDROME:I/L LMN type facial
nerve palsy&horizontal gaze palsy with C/L
hemiparesis due to involvement of horizontal
gaze centre,7th nerve nucleus&CST
 RAYMOND’S SYNDROME:I/L abducens palsy
C/L hemiparesis due to involvement of 6th
cranial nerve&CST

25.  MEDIAL MIDBRAIN SYNDROME:
1) ON THE SIDE OF LESION:Eye”down&out”
secondary to unopposed action of 4th&6th
cranial nerves,with dilated&unresponsive
pupil(3rd cranial nerve)
2) ON SIDE OPPOSITE LESION:paralysis of
face,arm,leg(CB&CS tracts in crus cerebri)
 LATERAL MIDBRAIN SYNDROME:
1) ON THE SIDE OF LESION:eye down&out
2) ON THE OPP. SIDE:
hemiataxia,hyperkinesias,tremor:Red
nucleus,dentatorubrothalamic pathway

26.  WEBER’S syndrome:third nerve palsy on the
I/L side due to involvement of occulomotor
nerve fascicles,Hemiplegia on C/L side due to
superior cerebral peduncle involvement
 CLAUDE’S syndrome:I/L 3rd nerve palsy,C/L
ataxia&tremor due superior cerebellar
peduncle involvement
 BENEDIKT’S syndrome:3rd nerve palsy on I/L
side&C/L side hemiparesis&ataxia due
involvement of red nucleus,SCP

27.  Lesion is dorsal midbrain
 Structures involved are quadrigeminal plate
region,periaqeuductal gray matter
 Clinical findings: impaired upgaze;
convergence&retraction nystagmus
 NOTHNAGEL’S SYNDROME:it is more a variant
of parinaud’s with U/L or B/L 3rd nerve
palsy.lesion is in midbrain tectum

28.  C/L homonymous hemianopia with visual sparing
is the usual manifestation
 ACUTE MEMORY DISTURBANCES:due to medial
temporal lobe&hippocampus involvement on the
dominant side
 ALEXIA without agraphia:due to dominant
hemisphere plus splenium of corpus callosum
involvement
 PEDUNCULAR HALLUCINOSIS:due to occlusion of
PCA

29.  ANTON’S syndrome:B/L infarction in distal
PCA produces cortical blindness
 If the visual association areas are spared and
only calcarine cortex is involved,patient may
be aware of his blindness
 BALINT’S syndrome:disorder of orderly visual
scanning of the environment due to bilateral
visual association area lesions,resulting from
infarctions secondary to low flow in the
watershed areas between the distal PCA&MCA
territories
 Pallinopsia&asimultognosia may also be seen

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