Cerebrovascular anatomy

A detailed presentation of cerebral vessels including developmental anatomy, course, branches, territories and clinical anatomy.

1. Cerebrovascular Anatomy Naresh Mullaguri MD Neurology Resident Physician PGY4 University of Missouri-Columbia

2. Cerebral Circulation Math

3. Cerebral Blood Flow and Brain Death

4. Embryology of Great cerebral Blood vessels

5. Variations in the Origin of the Great cerebral vessels

6. Branches of the Common carotid artery Paired arteries R ight side takes origin from the Brachiocephalic trunk at the level of Sternoclavicular joint L eft side takes origin from the arch of Aorta in the superior mediastinum at the level of second intercostal joint

7. External Carotid Artery Branches

8. Branches of the External Carotid Artery

9. Who don’t like Mnemonics

10. Ophthalmic Artery Originates at the level of Anterior Clinoid process of the ICA. So it is intradural at the site of origin, It supplies the contents of the orbit, Sphenoid sinus, Ethmoid air cells, Nasal mucosa, Dura mater of the Anterior Cranial Fossa, Skin of the Forehead, Root of the nose and Eyelids. In case of stenosis of the ICA, the cutaneous branches of the Ophthalmic artery forms anastomosis with the branches of the ECA.

11. PCOM In the early stages of the embryonic development, it is a proximal segment of the Posterior Cerebral Artery which is at first a branch of the ICA and only later comes to be supplied by the Basilar Artery. Fetal origin of the PCOM - 25% Joins the PCA at 10mm lateral to the Basilar tip. Most important anastomotic connection between the Anterior and Posterior circulation Perforating branches to Tubercinerium, mamillary body, Rostral thalamic nuclei, Subthalamus and part of Internal Capsule

12. Arterial Supply of the Interior of the Brain Anterior Choroidal Artery: Branch of ICA distal to the PCOM runs towards the occiput parallel to the Optic tract and then enters Choroidal fissure to supply the choroid plexus of the Temporal horn of the Lateral ventricle. It gives branches to Optic tract, Uncus, Hippocampus, Amygdala, Part of the Basal ganglia, Part of the Internal capsule. It also supplies part of fhe Pyramidal tract. Anastomotic connections with the Lateral posteriro Choroidal Artery.

13. CEREBRAL ARTERIAL TERRITORIES Middle Cerebral Artery Anteiror Cerebral Artery Posterior Cerebral Artery Anterior Choroidal Artery Posterior inferior Cerebellar Artery Superior Cerebellar Artery Lenticulostriate Arteries

14. The proximal section of the Anterior Cerebral Artery gives off Perforating branches to the Paraseptal region, Rostral portion of the Basal Ganglia, the diencephalon, Anteior limb of the Internal Capsule

15. RECURRENT ARTERY OF HEUBNER It is the large branch of Anterior Cerebral Artery that supplies the Basal Ganglia sometimes visible on the angiogram. It is the distal part of the medial Striate artery. Supplies the Anterior-medial section of the Caudate nucleus, Anterior-inferior section of the Internal Capsule as well as parts of the putamen and Septal nuclei

16. ACOM Aneurysm Rupture

17. MIDDLE CEREBRAL ARTERY

18. Cotical Branches of the Middle Cerebral Artery Orbitofrontal Prerolandic Rolandic Anterior Parietal Posterior Parietal Artery of Angular gyrus Temporo-occipital/Posterior Temporal Anterior Temporal

19. The cortical areas supplied by the MCA include Language areas of Broca and Wernicke, the Primary auditory cortex and gustatory cortex.

20. ARTERIES OF THE POSTERIOR FOSSA Vascular Anatomy in this region is highly variable Anterior Spinal Artery always arises from the Intradural portion of the Vertebral Artery

21. Vertebral Artery

22. POSTERIOR INFERIOR CEREBELLAR ARTERY Largest branch of Vertebral Artery Supplies the basal portion of the cerebellar hemispheres, The lower portion of the Vermis, part of the cerebellar nuclei and the choroid plexus of the IV ventricle and Dorsolateral portion of the Medulla Congenitally small vertebral artery may terminate as PICA and give off no contribution to the Basilar artery, which in such cases is simply a continuation of the contralateral vertebral artery

23. BASILAR ARTERY Arises from the union of Right and Left Vertebral arteries in front of the Brainstem at a lower pontine level Branches: 2 pairs of cerebellar arteries (AICA and SCA) and the Posterior Cerebral arteries Small perforating branches to Brainstem Paramedian branches, short and long circumferential branches.

24. ANTERIOR INFERIOR CEREBELLAR ARTERY First major branch of the Basilar artery Supplies the Flocculus, Anterior portion of the Cerebellar hemisphere Anastomoses with branches of PICA and its distribution is highly variable. Gives of Labyrinthine artery to the inner ear

25. SUPERIOR CEREBELLAR ARTERY Arises from the basilar artery below its tip and supplies the Rostral portion of cerebellar hemisphere and upper portion of the vermis As it curves around the midbrain, it gives off branches to the midbrain

26. POSTERIOR CEREBRAL ARTERY At an earlier stage in the ontogenic development, the PCA is a branch of ICA It originates at the Basilar bifurcation and then curves around the midbrain and enters the AMBIENT cistern where it has a close spatial relation to the tentorial edge Within the cistern, the PCA divides into major cortical branches including Calcarine, Occipito-temporal arteries and Temporal Branches

27. Thalamoperforating Branches Anteior and Posterior arteries Anterior TPA/Thalamotuberal artery: Mainly supplies the Rostral portion of the Thalamus Posteior TPA/Thalamoperforating Artery: Basal and medial portions of the Thalamus as well as the Pulvinar, Sometimes share a common trunk called the Artery of Percheron

28. Thalamogeniculate Artery DIstal to the origin of the PCOM It supplies the lateral portion of the Thalamus Posterior Choroidal Arteries Medial Branch : Supplies the midbrain and also the choroid plexus of the III ventricle Lateral Branch supplies the choroid plexus of the Lateral ventricle and has an anastomotic connection with the anterior choroidal artery. Both arteries supply the Geniculate bodies, Medial and posteromedial thalamic nuclei and the Pulvinar

29. CORTICAL BRANCHES OF THE PCA PCA territory is delimited by the Sylvian fissure. In others the MCA supplies the entire convexity of the Brain including the Occipital pole. The visual cortex of the calcarine sulcus is always supplied by the PCA. The optic radiation is however often supplied by the MCA so that homonymous hemianopsia doesn’t always incline an infarct in the territory of the PCA The PCA also has temporal branches to the temporal lobes

30. COLLATERAL CIRCULATION OF THE BRAIN COLLATERALS FROM EXTERNAL TO INTERNAL CAROTID CIRCULATION 1.External carotid artery - Facial Artery - Angular Artery - ICA 2.ECA - Superficial temporal artery - Angular Artery - ICA COLLATERALS FROM EXTERNAL TO VERTEBRAL CIRCULATION 1. ECA-Occipital Artery-Vertebral Artery CIRCLE OF WILLIS LEPTOMENIGEAL COLLATERALS CALLOSAL ANASTOMOSIS

31. Unlike the rest of the body Veins don’t run together with its arterial counterparts. The territories of the Cerebral arteries do not coincide with the cerebral veins Venous blood from Brain parenchyma crosses the subarachnoid and subdural spaces in short cortical veins like Superior anastomotic vein of Trolard, Dorsal superior Cerebral Vein, Superficial middle cerebral vein and Inferior Anastomotic vein of Labbe. VENOUS ANATOMY

32. Superolateral and Sagittal sections showing Cerebral veins

33. Deep Cerebral Veins Venous blood from the deep regions of the Brain including the Basal ganglia and thalamus drain into the paired Internal Cerebral veins and paired Basal Veins of Rosenthal Internal Cerebral veins are created by the confluence of the Septum Pellucidum with the Thalamostriate vein These 4 veins from both sides join behind the Splenium to form the Great Vein of Galen The Blood from there is drained into the Straight sinus (Sinus Rectus) and then into the confluence of sinuses (Confluence sinus, torcular herophili)

34. Dural Sinuses Superficial and deep veins of the Brain drain into the Dural Venous sinuses. Most of the venous drainage in the Superior Sagittal sinus travel from front to back which runs in the midline along the attachment of Falx Cerebri At the point in the back of the Head where the Falx cerebri merges with the Tentorium, the SSS is joined by the Straight sinus which runs in the midline along the attachment of tentorium and carries blood from deep regions of the Brain. The blood from the SSS and SS is then distributed to two Transverse Sinuses in the Torcula of Herophili (Winepress of Herophilus)

35. Dural Sinuses Contd... From the TS the blood drains into the Sigmoid sinuses and then to the Internal Jugular vein. The sinuses are often asymmetric and a number of variants of the venous drainage patterns.

36. Pterygoid Plexus Blood from the brain also drains into the viscerocranial system by the way of Pterygoid plexus. The cavernous sinus formed by the dural folds at the base of the Skull also drains from basal regions of the Brain; from the temporal lobes and from Orbit by way of Superior and Inferior Ophthalmic veins. It is connected to the Sigmoid sinus through Superior and Inferior Petrosal sinuses

37. Cerebral Venous Drainage Cortical Veins => Superior Sagittal Sinus Sphenoparietal sinus => Cavernous Sinus Vein of Labbe => Transverse Sinus Internal Cerebral Veins => Straight Sinus

38. VASCULAR ANATOMY OF SPINAL CORD Mostly anastomotic blood supply from Anterior Spinal Artery and paired Posterior Spinal arteries Anterior Spinal Artery: It runs down the ventral surface of the Spinal cord at the anterior edge of the anterior median fissure. It receives Segmental contribution from a number of arteries and supply to the ventral part of the spinal grey matter through perforating vessels known as SULCO-COMMISSURAL ARTERIES. Each artery supplies one half of the spinal cord, important structures supplied by the ASA include Anterior Horns, Lateral Spinothalamic tract and part of the Pyramidal tract.

39. POSTEROLATERAL SPINAL ARTERIES Paired Runs on the Dorsal side between the Posterior roots and lateral columns on either side. Supplies the posterior columns, roots and Dorsal horns The longitudinal axis are connected by radicular anastomosis . These arteries supply the anterior and Lateral columns through perforating branches. In the periphery however, the arteries of the spinal cord are functional end arteries. Intramedullary embolic occlusion of a Sulco-commissural artery therefore causes infarction of the Spinal cord.

40. ARTERIAL NETWORK OF SPINAL CORD Number of segmental arteries contribute to the blood supply of Spinal cord In the Upper Cervical Region, the anterior spinal artery receives most of the blood from the Vertebral artery Further down the cord, Longitudinal vessels receive blood from the Vertebral artery, subclavian artery or both. Segmental arteries preferentially arise from the Costocervical and Thyrocervical trunk. From T3 down, the ASA is fed by the Aortic branches The thoracic and Lumbar segmental arteries also contribute few branches to ASA or the posterolateral Spinal Arteries. Segmental artery is divided into Anterior and Posterior branches which enter the Spinal Canal with the anterior and Posterior root

41. GREAT RADICULAR ARTERY OR ARTERY OF ADAMKEIWICZ Large segmental artery supplying the lower Spinal cord T9-L1 THe developmental ascent of the Spinal cord makes this artery join the ASA at an acute angle (Hairpin configuration)

42. VENOUS DRAINAGE OF SPINAL CORD EPI-MEDULLARY VENOUS NETWORK Also called Internal Spinal venous plexus - Drains the spinal cord into the Subarachnoid area. These communicate with the radicular vein with the epidural venous plexus. EPIDURAL VENOUS PLEXUS Anterior and Posterior External Vertebral venous plexus Drains into the large veins of the Body.

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