Guo Ling , MD, PhD Department of Anatomy

1. Protection & Supply Apparatusesfor Central Nervous SystemMeninges of Brain and Spinal CordCerebral Spinal Fluid (CSF) Circulation Blood Vessels of Brain and Spinal Cord Guo Ling , MD, PhD Department of Anatomy

2. Meninges of brain & spinal cord(out inward) Spinal meninges dura mater arachnoid pia mater cerebral dura mater arachnoid cerebral pia mater spinal dura mater arachnoid spinal pia mater Meninges of Brain and Spinal Cord Concept：they are the connective tissue membranes covering the brain and the spinal cord (three layers) Cerebral meninges

3. Cerebral dura mater Arachnoid Cerebral pia mater

4. Spinal dura Spinal pia mater arachnoid

5. Spaces Formed by Meninges & Relative Contents 1.Epidural Space Location: lying between spinal dura and internal periosteum of the vertebral canal. Contents: roots of spinal nerve,venous plexuses,rich fat Feature: minus atmospheric pressure.

6. 2.Subarachnoid Space Location: lying between arachnoid and pia mater. Contents: cerebrospinal fluid (CSF) Features: plus pressure equal to the normal atmospheric pressure Locally enlarged spaces(5): terminal cistern(L2—S4) cerebellomedullary cistern interpeduncular cistern pontine cistern superior cistern Grains: arachnoid granulations 5 positions

7. 1.Inclusion: cerebral falx cerebellar falx cerebellar tentoriumdural sinuses 2.Communicationsamong the sinuses: Specific Structures Formed by Cerebral Dura Mater

8. 2.Communicationsamong the sinuses: Sup.sagittal sinus Inf.sagittal sinus→straight sinus→confluence of sinuses→transverse sinus→sigmoid sinus→inter jug v Cavernous sinus → sup.petrosal sinus inf.petrosal sinus

9. 3.Cavernous Sinus (1) Position:lying on each side of sella turcica (2) Contents:internal carotid artery & abducent nerve run through it ; and oculomotor,trochlear, ophthalmic(V1) & maxillary(V2) nerves pass through its lateral wall into the orbit. (3) Communication:facial v –-superior & inferior ophthalmic veins—--cavernous sinus (4) Clinical significances:bacterial or viral infection in the dangerous facial trigone may spread to the sinus via the above pathway causing sepsis & thrombosis in it and even negtively affecting the ajacent crainal nerves,in which relative symptoms & signs will appear.

11. Cerebrospinal Fluid(CSF) 1.Producing Position CSF is secreted by the choroid plexuses in all ventricles. 2. Circulation R&L lateral ventricles ↓interventricular ↓foramina third ventricle ↓cerebral aqueduct fourth ventricle ↓ R/L lateral foramina ↓ median foramen subarchnoid space ↓ arachnoid granulations superior sagittal sinus ↓ internal jugular vein

12. 3.Clinical Significances If the pathways of CSF circulation are blocked, CSF will not be able to return to the epidural sinuses, and will stagnate in cerebral ventricular system, leading to the swellen brain (hydrocephalus) especially in infants or children and to a high intrcranial pressure in adults in which the disfunctions of brain or cerebral hernias may appear, resulting to sudden death. .

14. Blood Vessels in CNS Arteries of CNS I. Brain Arteries 1.Origin two sets of arteries internal carotid artery vertebral artery

15. 2. Branches of Internal Carotid Artery (1) anterior cerebral a (2) middle cerebral a (3) anterior choroidal a (4) optic a (5) posterior communicating a The above branches of the artery collectively provide blood for the anterior 2/3 part of cerebral hemisphere including eyes, & anterior portion of thalamus.

16. (1)Anterior cerebral a supplies the medial surface of cerebrum & upper part of dorsal surface of the cerebrum.

17. (2)Middle cerebral a supplies most part of the dorsolateral surface of cerebral hemisphere.

18. (3) anterior choroidal a (4) optic a (5) posterior communicating a The three branches supply the areas with the same arterial names.

19. 3. Cerebral Arterial Circle(Willis`s) 1) Composition(5 parts, 9 branches ): anterior communicating A， bilateral anterior cerebral As, bilateralinternal carotid As， bilateralposterior communicating As, bilateralposterior cerebral As.

20. 2) Location: The circle lies on inferior surface of cerebrum & encircles optic chiasma, tuber cinereum & mammillary bodies. 3)Functions： The circle regulates blood flow of both cerebral hemispheres.

21. 4.Two Kinds of Arterial Branches Anterior ,middle and posterior cerebral arteries and the cerebral arterial circle all possesses the following: cortical branches central branches (IC,BN) Few anastomoses exist among separate branches . If a branch is blocked or broken, the target area suffers a deadly attact,either stroke or bleeding, resulting in losses of sensation & paralyses.

22. 5.Clinical Significances   1. The branches of cerebral arteries hardly establish anastomoses (so-called terminal As ). When one of them is blocked, the supplied regions of brain will completely lack blood supply, leading to neuronal necroses & apoptoses . 2. The arteries of brain seldom beat, which may link to their thin walls & their curved routes, bringing about no palpable pulses from the arteries. 3. The branches for internal capsule are easily broken and this may result in a worse bleeding, because they directly arise from middle cerebral A at a right angle and and their walls have to put up with the powerful rush force and high blood pressure from torrent blood flow.

23. II.Arteries of Spinal Cord 1.Four Origins Vertebral A Ascending cervical A Intercostal A Lumbar A

24. 2. Branches of Vertebral Artery & Basilar Artery Artery (1) ~ artery (5) are the branches of vertebral artery (1)anterior spinal artery (1) (2) posterior spinal arteries (1) (3) posterior inferior cerebellar arteries (2) (4) anterior inferior cerebellar arteries (2) (5) labyrinthine arteries (2) (7) pontine arteries (3 or 4 pairs ) (8) superior cerebellar arteries (2) (9) posterior cerebral arteries (2) Artery (7)~ Artery(9) are the branches of basilar artery The above branches collectively provide blood for the posterior 1/3 portion of cerebral hemisphere and posterior part of thalamus as well as the cerebellum, brain stem & spinal cord.

25. posterior cerebral A. superior cerebellar A labyrinthine A Ant.inf cerebellar A Ant.spinal A Vertebral A Post.inf.cerebellar A pontine A

26. 3.It supplies most parts of occipital and temporal lobes. Post.cerebral A

27. Basillar A Post. Spinal A Vertebral A Ant. spinal A Ascending cervical A Post. Intercostal A Lumbar A

28. Post spinal A 4.Arterial Distribution Patterns in Spinal Cord Ant. Spinal A Coronary A of spinal cord

29. III.Veins of Brain 1. Features (1) They own no relatively accompanying arteries. (2)There are two sets----superficial and deep veins. 2.Division (1) Superficial Vein ( 3 branches : sup, mid & inf ) They lie on the surface of the cerebrum and drains the blood from the cerebral cortex to venous sinuses : a. superior cerebral v (on the surface above LS ) →superior sagittal sinus b. middle cerebral v (situated in lateral sulcus--LS ) →cavernous sinus c. inferior cerebral v (on the surface under LS ) →cavernous sinus & transverse sinus

30. Superior cerebral V Sup.sagittal sinus Middle cerebral V Transverse sinus Inferior cerebral V Sigmoid sinus

31. (2)Deep veins drain the blood from the deep medullar matter to venous sinuses: a.Internal cerebral V b.Great cerebral Vstraight sinus (lying in postoinferior part of corpus callosum) c.Basilar V. Great cerebral vein is also called Galen`s vein.