VASCULATURE, CSF, AND
MENINGES
OBJECTIVES
• EXPLAIN HOW OXYGEN IS DELIVERED TO BRAIN TISSUE, HOW THE BRAIN IS SUSPENDED IN
LIQUID, AND HOW FLUID FLOWS BETWEEN THE SYSTEMS
• IDENTIFY DISORDERS OF VASCULAR SUPPLY, FORMATION AND PRESSURE IMBALANCES FROM
DESCRIPTIONS OF THE PROBLEM
• DURA – THICK FASCIA, 2 LAYERS
• OUTER LAYER ATTACHED TO SKULL
• INNER LAYER ATTACHED TO ARACHNOID, CONTINUOUS WITH SPINAL DURA
• SINUSES FORMED BY SPACES BETWEEN DURAL LAYERS
• ARACHNOID – THIN, FLEXIBLE CONNECTIVE TISSUE
• ATTACHED TO PIA WITH ARACHNOID TRABECULAE
• PIA – THINNEST LAYER
• FUSED TO SURFACE OF BRAIN
• FOLLOWS GYRI AND SULCI
MENINGES
SINUSES VS CISTERNS
• SINUSES – WITHIN DURA (BETWEEN LAYERS)
• CISTERNS – SUBARACHNOID SPACE
• SUPRASELLAR
• QUADRIGEMINAL
• INFRAPONTINE
• CISTERNA MAGNA
FALX CEREBRI AND TENTORIUM CEREBELLI
• FOLDS OF THE INNER LAYER OF DURA MATER SEPARATING THE CEREBRAL HEMISPHERES AND
THE CEREBRUM FROM THE CEREBELLUM
Outer layer of dura
Inner layer of dura
Left hemisphere
FALX CEREBRI
Right hemisphere
VIDEO FOR VISUALS ONLY
• HTTPS://WWW.YOUTUBE.COM/WATCH?V=J2OVJN2ALLE
• CRANIOSACRAL MOVEMENT IS BS, BUT THIS VIDEO IS USEFUL FOR THE VISUALS
VEINS AND SINUSES
• SSS
• ISS
• STRAIGHT
• CONFLUENCE
• TRANSVERSE
• SUP PETROSAL
• INF PETROSAL
• SIGMOID
• INTERNAL JUGULAR VEIN
CSF DRAINAGE
• CSF DRAINS FROM
SUBARACHNOID SPACE DIRECTLY
TO THE SINUSES
• ARACHNOID
VILLI/GRANULATIONS
VENTRICLES
• 1&2 – AKA LATERAL VENTRICLES,
IN HEMISPHERES
• INTERVENTRICULAR FORAMEN
(OF MONROE)
• 3 – IN DIENCEPHALON
• CEREBRAL AQUEDUCT
• 4 – IN
PONS/MEDULLA/CEREBELLUM
• 2 LATERAL & 1 MEDIAL
FORAMEN TO SUBARACHNOID
SPACE
LATERAL VENTRICLES
• ANTERIOR HORN
• BODY (SPLENIUM)
• ATRIUM
• POSTERIOR HORN
• INFERIOR HORN
CIRCLE OF WILLIS
• ENTERING CIRCLE: BASILAR ARTERY, INTERNAL
CAROTID ARTERIES
• WITHIN CIRCLE ONLY: POSTERIOR
COMMUNICATING, ANTERIOR
COMMUNICATING
• EXITING CIRCLE: POSTERIOR CEREBRAL, MIDDLE
CEREBRAL, ANTERIOR CEREBRAL
VIDEOS FOR YOUR REFERENCE
• HTTPS://WWW.YOUTUBE.COM/WATCH?V=9HHFM7RQHIM
• HTTPS://WWW.YOUTUBE.COM/WATCH?V=_YBXDHOS9FU
CEREBRAL ARTERIES
• EACH CEREBRAL ARTERY IS BROKEN INTO SEGMENTS TO UNDERSTAND LOCATIONS OF
STROKES MORE EASILY
• ACA HAS 5 SEGMENTS
• MCA HAS 4 SEGMENTS
• PCA HAS 4 SEGMENTS
ACA (PG 29 OF HAINES)
• A1 – PORTION OF ACA WITHIN THE CIRCLE OF WILLIS
• NO MAJOR BRANCHES
• A2 – PORTION OF ACA BETWEEN ANTERIOR COMMUNICATING AND BIFURCATION OF
PERICALLOSAL AND CALLOSOMARGINAL.*
• ORBITAL AND FRONTOPOLAR BRANCHES
• A3 – PERICALLOSAL ARTERY
• A4 AND A5 – SMALL TERMINAL BRANCHES OF ACA
*CALLOSOMARGINAL ARTERY EXISTS IN ABOUT 60% OF THE POPULATION
MCA (PG 39 OF HAINES)
• M1 – PORTION OF MCA BEFORE BIFURCATION
• SUPPLIES BASAL GANGLIA, CHOROID PLEXUS OF LATERAL VENTRICLES
• M2 – PORTIONS OF MCA COURSING OVER INSULA
• M3 – PORTIONS OF MCA COURSING ALONG UNDERSIDES (DEEP SURFACES) OF PARIETAL AND
TEMPORAL LOBES
• M4 – BRANCHES OF MCA SUPPLYING LATERAL SURFACE OF CORTEX:
• ORBITOFRONTAL, PREROLANDIC, ROLANDIC, ANTERIOR AND POSTERIOR PARIETAL BRANCHES,
ANGULAR, ANTERIOR AND POSTERIOR TEMPORAL BRANCHES.
PCA (PG 21 OF HAINES)
• P1 – PORTION OF PCA WITHIN CIRCLE OF WILLIS
• SUPPLIES MIDBRAIN, THALAMUS, CHOROID PLEXUS OF LATERAL AND 3RD VENTRICLES
• P2 – PORTION OF PCA OUTSIDE OF CIRCLE, BEFORE MAJOR BRANCHES
• P3 – ANTERIOR TEMPORAL, POSTERIOR TEMPORAL, AND CONTINUATION OF PCA
• P4 – PARIETO-OCCIPITAL, CALCARINE
VERTEBROBASILAR SYSTEM
• BLOOD SUPPLY TO THE BRAINSTEM AND CEREBELLUM!
• INFERIOR TO SUPERIOR:
• VERTEBRAL A
• POSTERIOR INFERIOR CEREBELLAR A
• ANTERIOR SPINAL A
• BASILAR A (ONLY ONE NOT PAIRED)
• ANTERIOR INFERIOR CEREBELLAR A
• PONTINE A
• SUPERIOR CEREBELLAR
• PCA
DISORDERS
• HEMATOMAS (SUBDURAL AND EPIDURAL)
• HYDROCEPHALUS
• INTRACRANIAL PRESSURE
• HERNIATIONS
• UNCAL
• CENTRAL
• TONSILLAR
• STROKES (CEREBROVASCULAR ACCIDENTS)
• INFARCTION VS HEMORRHAGE
• TRANSIENT ISCHEMIC ATTACK (TIA)
• COMPLETED STROKE
• PROGRESSIVE STROKE
• ANEURYSMS
• ARTERIOVENOUS MALFORMATIONS
DISORDER IDENTIFICATION
• BLOOD FROM A VEIN POOLS IN THE SUBDURAL SPACE
• BLOOD FROM AN ARTERY POOLS IN THE SUBARACHNOID SPACE
• BLOOD FROM AN ARTERY POOLS IN THE EPIDURAL SPACE
• AN EMBOLUS OCCLUDES THE MCA WITH SYMPTOMS LASTING LESS THAN 24 HOURS
• AN EMBOLUS OCCLUDES THE ACA WITH SYMPTOMS LASTING LONGER THAN 24 HOURS