Gross anatomy of the posterior cerbral circulation

1. POSTERIOR
CIRCULATION
Dr D Sudeepta Rao
PG-General Medicine
DCMS

2. Vertebrobasilar System
 Vertebral arteries
 Basilar artery
 Posterior cerebral arteries

3. VERTEBROBASILAR SYSTEM

4. Blood Supply
 Upper spinal cord
 Brain stem
 Cerebellum
 Occipital lobe
 Part of Temporal lobe
 Thalamus
 Hypothalamus

5. Vertebral artery(VA)
 Subclavian artery
 Ascend in foramina transversaria
 Upper six cervical vertebra
 Enter cranial cavity thro foramen
magnum
 Anterolateral aspect of medulla
 Divided into 4 parts: V 1 to V 4

7. DIVISIONS:

8. “SUBCLAVIAN STEAL”
• Subclavian occluded
proximal to origin of
vertebral.
• Leads of reversal in the
direction of blood flow in the
ipsilateral vertebral artery.
• Exercise of ipsilateral arm
may increase demand on
vertebral flow, leading to
posterior circulation TIAs.

9. Branches of VA
 Anterior spinal artery
◦ Join at mid medullary level
◦ Descend on ventral midline of spinal cord
◦ Supply triangular area of medulla
oblongata

10. Branches of VA(contd…)
 Posterior inferior cerebellar artery
◦ Largest branch
◦ Ascends behind the roots of the ix & x cr.
Nerves
◦ Turns laterally into cerebellar vallecula
◦ Medial and lateral branches
◦ Supply medulla oblongata dorsal to
olivary nucleus & lateral to xii nucleus

11. Branches of VA(contd…)
 Posterior spinal artery
Arises from pica
 Minute medullary branches

12. Branches of VA:

13. BRANCHES OF VA

14. Blood supply of Medulla

15. Basilar artery(BA)
 Arise at Lower border of pons
 Extend upto upper border of pons
 Large median vessel formed by union
of vertebral arteries
 Terminates by dividing into 2 posterior
cerebral arteries at the
interpeduncular fossa

16. Branches of Basilar artery
 Pontine branches
 Anterior inferior cerebellar artery
◦ Lower part of BA
◦ Labyrinthine artery
◦ Supplies inferior cerebellar surface
anterolaterally
◦ Anastomose with PICA
◦ Few branches to inferolateral pons
 Superior cerebellar artery

17. Branches of Basilar
artery(contd..)
 Superior cerebellar artery
◦ Distal portion of BA
◦ Oculomotor nerve separates it from
posterior cerebral artery
◦ Trochlear nerve laterally

18. Branches of Basilar artery

19. Branches of Basilar artery

20. Branches of Basilar artery

21. Posterior Cerebral
Artery(PCA)
 Terminal branch of basilar artery
 Surgical nomenclature identifies 3
segments:
◦ P1 basilar bifurcation to post
communicating a
◦ P2 portion in perimesencephalic cistern
◦ P3 portion in the calcarine fissure
 Supplies temporal and occipital lobes
◦ Has cortical and perforate/central
branches

22. PCA: Cortical Branches
 Temporal branches usually two supply
◦ Uncus
◦ Parahippocampus
◦ Medial and lateral occipetotemporal gyri
 Occipital branches supply
◦ Cuneus
◦ Lingual gyrus
◦ Posterolateral surface of the occipetal
lobe

23. Posterior Cerebral Artery
 Supplies visual areas of the cerebral
cortex
 Concept of Macular sparring

24. Posterior Cerebral Artery

25. PCA: Central branches
 Supply subcortical structures
 Posteromedial central branches(thalamo
perforate)
◦ Ant thalamus, subthalamus, latral wall of third
ventricle and globus pallidus
 Posterolateral central branches(thalamo
geniculate)
◦ Supply peduncle posterior thalamus, MGB,
superior &inferior colliculi
 Posterior choroidal branch
◦ LGB & ends in the lateral ventricle

26. PCA: Central branches

27. Thalamus blood supply

28. PCA: Cortical Branches

29. Blood supply of the spinal
cord
 Anterior spinal artery in anterior
median fissure
 Two Posterior spinal arteries in the
posterolateral sulcus
 Arterial vasocorona an arterial plexus
in the pia mater

30. Blood supply of the spinal
cord

31. Main source of blood
 Main source of blood to spinal arteries
 Vertebral arteries upto cervical
segments
 Radicular ateries that reach the cord
along spinal nerve roots

32. Main source of blood

33. THANK YOU