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

MENINGES

• 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

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

Right hemisphere

FALX CEREBRI

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