Posterior cerebral circulation - Gross Anatomy

Gross anatomy of the posterior cerbral circulation

1. POSTERIOR CIRCULATION Dr D Sudeepta R ao 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

6. DIVISIONS:

7. 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. “SUBCLAVIAN STEAL”

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

9. 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

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

11. Branches of VA:

12. BRANCHES OF VA

13. Blood supply of Medulla

14. Basilar artery(BA) A rise 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

15. 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

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

17. Branches of Basilar artery

18. Branches of Basilar artery

19. Branches of Basilar artery

20. 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

21. PCA: Cortical Branches Temporal branches usually two supply Uncus Parahippocampus Medial and lateral occipetotemporal gyri Occipital branches supply C uneus Lingual gyrus Posterolateral surface of the occipetal lobe

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

23. Posterior Cerebral Artery

24. 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

25. PCA: Central branches

26. Thalamus blood supply

27. PCA: Cortical Branches

28. 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

29. Blood supply of the spinal cord

30. 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

31. Main source of blood

32. THANK YOU