1. Blood Supply Fall 2012 General Concepts Internal Carotid Artery
Vertebral Artery
Circle of Willis
Fall 2012

2. Cerebral Blood Flow Central nervous system
2% of body by weight
15% of all cardiac output
20% of all O2 consumed
Total brain blood volume every 5-7/min
Loss of consciousness after 10 sec
Necrosis after 4-5 min of hypoxia

3. Cerebral Blood Flow
Arterial supply to brain and much of spinal cord derived from 2 sets of arteries
Internal carotid arteries
Anterior circulation - 80% of blood supply
Vertebral arteries
Posterior circulation - 20% of blood supply
Linear extent of capillaries/Unit volume
Gray matter > White matter
Sensory, interneurons > Motor

4. Internal Carotid Artery
Common Carotid Artery
Off Brachiocephalic Trunk – Right
Off Arch of Aorta - Left
Subclavian Artery

5. Normally at superior border of thyroid cartilage = C4 vertebra
Carotid Bifurcation
<1% 4% 12% 30%
35% 12% 5% 1%
Normally at superior border of thyroid cartilage = C4 vertebra

6. Ophthalmic Artery
Optic Nerve
Ophthalmic Artery
ICA

7. ICA Branches Anterior Cerebral A. Middle Cerebral A. ICA Post. Comm.
Artery
Anterior
Choroidal
Artery

8. ICA Branches Anterior Cerebral Artery Ophthalmic Artery ICA
Middle Cerebral Artery
Anterior Choroidal Artery
Posterior
Communicating
Artery

9. Anterior Choroidal Artery
AChA = yellow

10. Anterior Cerebral Artery
Communicating
Artery
ACA

11. (Recurrent A. of Heubner)
Anterior Cerebral Artery
Anterior Communicating Artery
Medial Striate Artery
(Recurrent A. of Heubner)
ACA

12. Anterior Cerebral Artery
ACA

13. Anterior Cerebral Artery
Frontopolar
branches
Internal frontal
branches
Paracentral
branches
Internal parietal
branches

14. Anterior Cerebral Artery
ACA = pink

15. Middle Cerebral Artery
ACA
Middle Cerebral A.
M1 segment

16. Middle Cerebral Artery Subdivisions

17. Middle Cerebral Artery
Medial Striate Artery
Lateral Striate As. M1
ACA

18. Middle Cerebral Artery
Post. Parietal A.
Ant. Parietal A.
Central A.
Precentral A.
Frontal A.
Orbital A.
MCA, sup. trunk
Angular A.
MCA
Temporal As.
MCA, inf. trunk

19. Middle Cerebral Artery
MCA = green

20. Vertebral Artery Variants Left off arch of aorta 4% Left dominant 60%
Right hypoplastic 10%
Left hypoplastic 5%
Left atretic, no communication with basilar 3%
Right atretic, no communication with basilar 2%
Subclavian Artery

21. Vertebral Artery C1 C2 C3 1% 2% 5%
90% C4 C5 C6 C7 T1

22. Vertebral Artery

23. Vertebral Artery Basilar Artery Vertebral Artery PICA
Anterior Spinal Artery
PICA

24. Vertebral Artery Basilar Artery Vertebral Artery
Posterior Spinal Artery
(25%)
Anterior Spinal Artery

25. Vertebral Artery Basilar Artery PICA Vertebral Artery
Posterior Spinal Artery
(75%)
Anterior Spinal Artery

26. Spinal Arteries

27. Spinal Arteries

28. Spinal Arteries
Artery of Adamkiewicz

29. PICA
Basilar Artery
PICA

30. Basilar Artery - Branches
Pontine Arteries
Basilar Artery
AICA
Labyrinthine Artery

31. Basilar Artery - Branches
Posterior Communicating Artery
Posterior Cerebral Artery
CN III
Superior Cerebellar Artery

32. Basilar Artery - Branches
Posterior Communicating Artery
Posterior Cerebral Artery
CN III
Superior Cerebellar Artery

33. Basilar Artery - Branches
Posterior
Cerebral Artery
CN III
Basilar Artery
Superior Cerebellar Artery
CN VI

34. Cerebellar Arteries

35. Posterior Cerebral Artery

36. Posterior Cerebral Artery
Parieto-occipital Artery
Calcarine Artery
PCA

37. Posterior Cerebral Artery
PCA = blue

38. Circle of Willis Anterior Communicating Artery
Anterior Cerebral Artery
Internal Carotid Artery
Posterior Communicating Artery
Posterior Cerebral Artery
Basilar Artery

39. Circle of Willis Anterior Communicating Artery
Anterior Cerebral Artery
Internal Carotid Artery
Posterior Communicating Artery
Posterior Cerebral Artery
Basilar Artery

40. Circle of Willis Anterior Communicating Artery Superior
Hypophyseal
Artery
Anterior Cerebral Artery
Internal Carotid Artery
Posterior Communicating Artery
Inferior
Hypophyseal
Artery
Posterior Cerebral Artery

41. Circle of Willis Variations
10%
10%
10%
60%
complete
10%
10%
10%

42. Watershed Zones

43. Venous Dural Sinuses Inferior Sagittal Superior Sagittal
Sphenoparietal
Straight
Inferior Petrosal
Confluens
Occipital
Transverse
Sigmoid

44. Venous Dural Sinuses Superior Sagittal Sinus Inferior Sagittal Sinus
Occipital
Sinus
Straight Sinus

45. Venous Dural Sinuses Superior Ophthalmic Vein Sphenoparietal Cavernous
Superior Petrosal
Inferior Petrosal
Sigmoid
Straight
Superior Sagittal
Transverse

46. Medulla Blood Supplies

47. Caudal Medulla
PSA / PICA
ASA / VA
ASA

48. Rostral Medulla
PICA
PSA / PICA
ASA / VA

49. Pons Blood Supplies

50. Caudal
Pons
BA / AICA BA

51. Rostral
Pons
SCA
BA / SCA BA

52. Midbrain Blood Supplies

53. Caudal Midbrain
SCA /
PCA
BA /
SCA

54. Rostral Midbrain
PCA
PCA
PCA
PCoA
Ant Ch A