Presentation on theme: "Guo Ling , MD, PhD Department of Anatomy"— Presentation transcript:
1 Guo Ling , MD, PhD Department of Anatomy Protection & Supply Apparatuses for Central Nervous System Meninges of Brain and Spinal Cord Cerebral Spinal Fluid (CSF) Circulation Blood Vessels of Brain and Spinal CordGuo Ling , MD, PhDDepartment of Anatomy
2 Meninges of Brain and Spinal Cord Concept：they are the connective tissue membranes covering the brain and the spinal cord (three layers)Meninges of brain & spinal cord(out inward)Spinalmeningesdura materarachnoidpia matercerebral dura matercerebral pia materspinal duramaterspinal pia materCerebralmeninges
5 Spaces Formed by Meninges & Relative Contents 1.Epidural SpaceLocation: lying between spinal dura and internalperiosteum of the vertebral canal.Contents: roots of spinal nerve,venous plexuses,rich fatFeature: minus atmospheric pressure.
6 Location: lying between arachnoid 2.Subarachnoid SpaceLocation: lying between arachnoidand pia mater.Contents: cerebrospinal fluid (CSF)Features: plus pressure equal to thenormal atmospheric pressureLocally enlarged spaces(5):terminal cistern(L2—S4)cerebellomedullary cisterninterpeduncular cisternpontine cisternsuperior cisternGrains:arachnoid granulations5 positions
7 Specific Structures Formed by Cerebral Dura Mater 1.Inclusion: cerebral falx cerebellar falxcerebellar tentorium dural sinuses2.Communications among the sinuses:
8 Cavernous sinus → sup.petrosal sinus inf.petrosal sinus 2.Communications among the sinuses:Sup.sagittal sinusInf.sagittal sinus→straight sinus→confluence of sinuses→transverse sinus→sigmoid sinus→inter jug vCavernous sinus → sup.petrosal sinusinf.petrosal sinus
9 3.Cavernous Sinus (1) Position: lying on each side of sella turcica (2) Contents: internal carotid artery & abducent nerverun through it ; and oculomotor,trochlear,ophthalmic(V1) & maxillary(V2) nerves passthrough its lateral wall into the orbit.(3) Communication: facial v –-superior & inferiorophthalmic veins—--cavernous sinus(4) Clinical significances: bacterial or viral infectionin the dangerous facial trigone may spread tothe sinus via the above pathway causing sepsis& thrombosis in it and even negtively affectingthe ajacent crainal nerves,in which relativesymptoms & signs will appear.
11 ↓ arachnoid granulations Cerebrospinal Fluid(CSF)1.Producing PositionCSF is secreted by the choroidplexuses in all ventricles.2. CirculationR&L lateral ventricles↓interventricular↓foraminathird ventricle↓ cerebral aqueductfourth ventricle↓ R/L lateral foramina↓ median foramensubarchnoid space↓ arachnoid granulationssuperior sagittal sinus↓internal jugular vein
12 3.Clinical Significances If the pathways of CSF circulation areblocked, CSF will not be able to return tothe 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 disfunctionsof brain or cerebral hernias may appear,resulting to sudden death. .
14 I. Brain Arteries 1.Origin Blood Vessels in CNS Arteries of CNS two sets of arteriesinternal carotid arteryvertebral 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 aThe 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 branchessupply the areas withthe same arterial names.
20 2) Location: The circle lies on inferior surface of cerebrum & encirclesoptic chiasma,tuber cinereum &mammillary bodies.3)Functions：The circle regulatesblood flow of bothcerebral hemispheres.
21 cortical branches 4.Two Kinds of Arterial Branches Anterior ,middle and posterior cerebral arteriesand the cerebral arterialcircle all possessesthe following:cortical branchescentral branches (IC,BN)Few anastomoses exist among separate branches . If a branchis blocked or broken, the targetarea suffers a deadly attact,either stroke or bleeding, resulting inlosses 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 OriginsVertebral AAscending cervical AIntercostal ALumbar A
24 2. Branches of Vertebral Artery & Basilar 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 (1) ~ artery (5) are the branches of vertebral arteryArtery (7)~ Artery (9) are thebranches of basilar arteryThe 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.
26 3.It supplies most parts of occipital and temporal lobes. Post.cerebral A
27 Basillar AVertebral APost.Spinal AAnt.spinal AAscendingcervical APost.Intercostal ALumbar A
28 4.Arterial Distribution Patterns in Spinal Cord Post spinal A4.Arterial DistributionPatterns in Spinal CordAnt. Spinal ACoronary A of spinal cord
29 III.Veins of Brain1. 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 drainsthe blood from the cerebral cortex to venous sinuses :a. superior cerebral v (on the surface above LS )→superior sagittal sinusb. middle cerebral v (situated in lateral sulcus--LS )→cavernous sinusc. inferior cerebral v (on the surface under LS )→cavernous sinus & transverse sinus
31 Great cerebral vein is also called Galen`s vein. (2)Deep veins drain the blood from the deepmedullar matter to venous sinuses:a.Internal cerebral Vb.Great cerebral V straight sinus(lying in postoinferiorpart of corpus callosum)c.Basilar V.Great cerebralvein is also calledGalen`s vein.