1. M2 Unit
Presented by M.SATHISH KUMAR

2. Stroke syndromes
Cluster of signs and symptoms
produced due to the occlusion of an
artery(due to an atherothrombotic
lesion or an emboli or dissection )
supplying a particular region of the
brain

3. classification
Large vessel stroke within the
anterior circulation
Large vessel stroke within the
posterior circulation
Small vessel disease of either
vascular bed

4. Cerebral circulation
Anterior circulation- MCA, ACA,
and Anterior choroidal artery
Posterior circulation-Vertebral
artery, Basilar artery and Posterior
cerebral artery

5. Circle of Willis

6. Anterior and posterior circulation

7. Stroke within the anterior
circulation
Due to occlusion of Internal carotid
artery and its branches
 Middle cerebral artery, Anterior
cerebral artery and Anterior
choroidal artery

8. Middle cerebral Artery
M1 segment(proximal)- deep
penetrating or lenticulostriate
branches– Internal capsule, caudate
nuclues, putamen and outer
pallidus

9. M1 segment

10. Cerebral Hemisphere in coronal
Section

11. M2 Segment
M2(distal)- superior and inferior
divisions- the entire superolateral
surface of frontal and parietal lobe
except frontal pole, strip along the
superomedial frontal and parietal
cortex, occipital lobe convolutions
and medial temporal cortex

12. M2 segment

13. Complete MCA syndrome
Contralateral hemiplegia
Contralateral hemianaesthesia
Contralateral homonymous hemianopia
Gaze preference to the ipsilateral side
If dominant hemisphere involved-Global
aphasia
If non dominant hemisphere involved-
Hemispatial neglect, anasognosia and
constructional apraxia

14. Partial syndromes
M1 syndrome-occlusion of
lenticulostriate branches-
If ischemia of internal capsule
produces pure motor or sensorymotor
stroke contralateral to the side of
lesion
If ischemia of putamen, pallidus-
predominantly parkinsonian features

15. Cerebral Hemisphere in coronal
Section

16. 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

17. M2 syndrome
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

18. M2 segment

19. Anterior Cerebral artery
A1 segment- from internal carotid to
anterior communicating artery-
branches to anterior limb of internal
capsule, anteroinferior caudate,
anterior hypothalamus
A2 segment-distal to anterior
communicating artery- supplies
frontal pole, entire medial part of
cerebral hemispheres

20. Precommunal A1 segment

21. Post communal A2 segment

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

23. A2 syndrome
 Motor area for leg and foot-c/l paralysis of foot and
leg
 Sensory area for foot and leg-c/l cortical sensory
loss of foot and leg
 Sensorimotor area in paracentral lobule-urinary
incontinence
 Medial surface of posterior frontal lobe-c/l grasp
and suckling reflex
 Cingulate gyrus and the medial inferior portions of
frontal, parietal and temporal lobes-abulia

24. Anterior choroidal 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

25. Others
Internal carotid artery
Common carotid artery

26. Stroke within the posterior
circulation
Paired Vertebral arteries
Basilar artery
 Paired Posterior cerebral arteries
Gives small penetrating branches
and short and long circumferential
branches

27. Posterior circulation

28. Posterior circulation
Supplies
 Cerebellum
 Medulla
 Pons
 Midbrain
 Thalamus
 Subthalamus
 Hippocampus
 Medial part of temporal lobe
 Occipital lobe

29. Posterior cerebral artery
P1 segment-Precommunal-
Midbrain, thalamus and
subthalamus
P2 segment-Temporal and occipital
cortex

30. P1 syndromes
Due to the involvement of
ipsilateral subthalamus, cerebral
peduncles and midbrain

31. P1 syndrome
Midbrain
Claudes- 3rd nerve palsy with c/l ataxia-
Red nuclues
Webers- 3rd nerve palsy with c/l
hemiplegia-Cerebral peduncle
Subthalamus-c/l hemiballismus
Thalamus- Thalamic dejerine Roussy
syndrome- c/l hemisensory loss followed
later by severe agonising pain

32. Midbrain Syndromes

33. P2 syndromes
Infarction of medial temporal and
occipital lobes
Occipital lobe-c/l homonymous
hemianopia with macular sparing, if
visual association area spared, patient
aware of visual defect
Medial temporal lobe- Memory
impairement
Visual hallucinations

34. 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

35. P2 syndromes

36. Vertebral(V4) and PICA arteries

37. V4 and PICA
V1 and V4- prone for
atherothrombosis
If V1 occlusion
If occlusion is in subclavian artery
proximal to origin of vertebral
artery-subclavian steal syndrome

38. Lateral medullary
syndrome(Wallenburgs)
 Caused due to occlusion of V4 segment or PICA
 Descending tract and nucleus of trigeminal nerve- Pain,
numbness and abnormal sensation over one half of face
 Vestibular nucleus-Vertigo, nausea, vomiting and diplopia
 Issuing fibres of 9th and 10th nerve nucleus- Dysphagia,
hoarseness, palatal paralysis
 Restiform body, and cerebellar hemispheres-Ataxia of
limbs
 Descending sympathetic tract-Horners syndrome
 Spinothalamic tract- c/l loss of pain and temperature

39. Medullary syndromes

40. Medial medullary syndrome
Infarction of pyramid- c/l hemiplegia
of arm and leg, sparing face
If medial lemniscus-c/l loss of tactile
and proprioception
If hypoglossal nerve nucleus involved-
ipsilateral LMN hypoglossal nerve
palsy – atrophy of half of tongue.

41. Basilar Artery
Paramedian- wedge of pons in
midline
Short circumerential- lateral two
thirds of pons and middle and
superior cerebellar peduncles
 Long circumferential- Superior and
anterior inferior cerebellar

42. Basilar artery syndromes
Occlusion of basilar artery-b/l
brainstem signs
Occlusion of basilar branch artery-
unilateral motor, sensory and
cranial nerves

43. Basilar artery syndromes
Complete basilar artery
occlusion(Locked in state)-b/l long
tract(sensory/motor) with cranial
nerve and cerebellar dysfunction-
preserved
consciousness,quadriplegia and
cranial nerve signs

44. Basilar artery branch-syndrome of anterior inferior
cerebellar artery(lateral inferior pontine syndrome)
Anterior inferior cerebellar artery-
lateral part of inferior pons and
anterior part of inferior cerebellar
hemispheres
 Cerebellum-Ataxia of limb and gait
 7th nerve nuclues- Facial weakness
 8th nerve nucleus-Deafness, tinnitus, vertigo, nausea,
vomiting
 Spinothalamic tract-c/l loss of pain and temperature

45. Inferior pontine syndrome

46. Basilar artery branch-Syndrome of superior cerebellar
artery(Lateral superior pontine syndrome)
Superior cerebellar artery- lateral
part of superior pons and superior
surface of cerebellar hemispheres
 Superior and middle cerebellar peduncles and
superior cerebellar hemisphere-Ataxia of limb and
gait
 Vestibular nucleus-dizziness, nausea and vomiting
 Spinothalamic tract-c/l loss of pain and
temperature

47. Superior pontine syndrome

48. Medial pontine syndromes
Caused due to occlusion of
paramedian and short circumferential
branches of basilar artery
Corticobulbar and corticospinal-c/l
face, arm and leg paralysis
Cerebellar peduncles-ataxia of limb
and gait

49. Reference: Harrisons 18e