B7 NEURO PKT 3: VENTRICULAR SYSTEM & CSF

CSF vs. plasma

(CSF has) higher [ ]s of: Cl Na Mg Lower [ ]s of: K Ca glucose very little protein only 1-5 cells per mL (leukocytes)

CSF normal volume is

120-150mL made @ rate of 450-500 mL/day CSF pool is turned over 3-4 X per day *requires E to make CSF

THE TELA CHOROIDEA OF THE 3RD VENTRICLE

2 LAYERED MEMBRANE MADE OF PIA MATTER AND EPENDYMAL CELLS FORMS THE SUPERIOR BORDER/ROOF OF THE 3RD VENTRICLE (ALONG WITH THE CHOROID PLEXUS)

INFERIOR/TEMPORAL HORN OF THE LATERAL VENTRICLE IS LOCATED WHERE?

3CM POSTERIOR TO TEMPORAL POLE

THE CAVITY OF THE DIENCEPHALON

3RD VENTRICLE (IT'S NARROW AND VERTICALLY ORIENTED IN MIDLINE SPACE)

CAVITY OF THE HINDBRAIN/RHOMBENCEPHALON

4TH VENTRICLE

THE ANTERIOR HORN OF THE LATERAL VENTRICLES IS LOCATED WHERE?

ANT. TO IV FORAMEN

INFERIOR/TEMPORAL HORN BOUNDARIES

ANTERIOR END: AMYGDALOID BODY IS JUST BEYOND ROOF: TAIL OF CAUDATE & STRIA TERMINALIS FLOOR: HIPPOCAMUS CHOROID PLEXUS IS PRESENT

5 PARTS OF THE LATERAL VENTRICLES

ANTERIOR/FRONTAL HORN BODY ATRIUM/TRIGONE POSTERIOR/OCCIPITAL HORN INFERIOR/TEMPORAL HORN

WHAT FOLLOWS THE DURAL LINING AND THE DURAL SEPTA?

ARACHNOID

WHAT IS THE TRIANGULAR, MOST EXPANDED PART OF THE LATERAL VENTRICLE?

ATRIUM/TRIGONE IT LIES POSTERIOR TO THE PULVINAR OF THE THALAMUS

important differential diagnosis of normal pressure hydrocephalus

Alzheimer's disease Parkinson's disease

WHAT IS SUSPENDED IN THE SUBARACHNOID SPACE

BRAIN SPINAL CORD AA. VV. NN. ARACHNOID TRABECULAE CSF

WHAT IS THE ELEVATION IN THE MEDIUAL WALL OF THE POST. HORN OF THE LAT VENTRICLE?

CALCAR AVIS --> IT IS CAUSED BY THE CALCARINE SULCUS

THE GLOMUS CHOROIDEUM (FOUND IN THE ATRIUM OF THE LV) CAN CONTAIN WHAT IN ELDERLY PTS?

CALCIFICATIONS THAT ARE VISIBLE ON RADIOGRAPHS OR CTs

THE SPINAL CORD

CENTRAL CANAL

WHAT IS THE NARROWEST PART OF THE VENTRICULAR SYSTEM?

CEREBRAL AQUEDUCT--> THUS= COMMON SITE OF OCCLUSION--> OCCLUSION CAUSES AN OBSTRUCTIVE HYDROCEPHALUS

AREAS OF SUBARACHNOID SPACE THAT ARE WIDER

CISTERNS

WHAT FOLLOWS THE CONTOUR OF THE SKULL?

DURA

THE VENTRICULAR SYSTEM IS LINED BY WHAT?

EPENDYMAL CELLS

THE 4TH VENTRICLE

EXTENDS LATERALLY OVER SURFACE OF UPPER MEDULLA AS LATERAL RECESSES...ENDING @ LATERAL APERTURES/FORAMINA OF LUSCHKA (@ ENDS OF LATERAL RECESSES ARE 2 OF 3 OPENINGS -->LATERAL APERTURES)

THE FLOOR & ROOF OF THE 4TH VENTRICLE

FLOOR=DORSAL SURFAC OF PONS & UPPER MEDULLA (RHOMBOID FOSSA) ROOF: SUPERIORLY = SUPERIOR CEREBELLAR PEDUNCLES AND SMV INFERIORLY: TELA CHOROIDEA OF 4TH V. W/ CHOROID PLEXUS

THE ATRIUM/TRIGONE (OF THE LV) CONTAINS A LARGE TUFT OF CHOROID PLEXUS KNOWN AS WHAT?

GLOMUS CHORIDEUM

THE IV FORAMEN IS LOCATED WHERE?

IN THE ANTERIOR PART OF THE LATERAL WALLS OF THE 3RD VENTRICLE

VENTRICULAR SYSTEM

INTERCONNECTED CAVITIES AND CHANNELS DERIVED FROM THE LUMEN OF THE EMBRYONIC NEURAL TUBE

SO, THE SUBARACHNOID SPACE

IS NOT NOT NOT OF UNIFORM WIDTH!

WHAT IS THE COMMUNICATION BETWEEN THE LATERAL AND 3RD VENTRICLES?

IV FORAMEN

BODY OF THE ANTERIOR HORN OF THE LV EXTENDS FROM

IV FORAMEN --> SPLENIUM OF CORPUS CALLOSUM

VENTRICULAR SYSTEM OF THE BRAIN INCLUDES WHAT VENTRICLES?

LATERAL VENTRICLES - 1 ON EACH CEREBRAL HEMISPHERE 3RD VENTRICLE-DIENCEPHALON CEREBRAL AQUEDUCT-MIDBRAIN 4TH VENTRICLE- BETWEN CEREBELLUM, PONS, AND UPPER MEDULLA

BOUNDARIES OF THE 3RD VENTRICLE

LATERAL: THALAMUS AND HYPOTHALAMUS ANTERIOR: ANTERIOR COMMISSURE & LAMINA TERMINALIS INFERIOR: HYPOTHAL & UPPER MIDBRAIN POST: OPENING OF CEREBRAL AQUEDUCT, POST. COMMISSURE, PINEAL BODY SUPERIOR: TELA CHOROIDEA OF 3RD VENTRICLE WITH CHOROID PLEXUS

BOUNDARIES OF ANTERIOR HORN OF THE LV

MEDIAL: SEPTUM PELLUCIDUM LATERAL: HEAD OF CAUDATE NUCLEUS SUPERIOR: CORPUS CALLOSUM ANT: GENU OF CORPUS CALLOSUM NO CHOROID PLEXUS

BOUNDARIES OF THE BODY OF THE ANT. HORN OF THE LV

MEDIAL: SEPTUM PELLUCIDUM & FORNIX LATERAL: BODY OF CAUDATE SUPERIOR: CORPUS CALLOSUM INFERIOR: THALAMUS CHORID PLEXUS IS PRESENT

WHAT IS THE ONLY COMMUNICATIONS BETWEEN THE VENTRICULAR SYSTEM AND THE SUBARACHNOID SPACE?

MEDIAN AND LATERAL APERTURES OF THE 4TH VENTRICLE

THE TELA CHOROIDEA HAS AN INFERIOR MEDIAN OPENING

MEDIAN APERTURE/FORAMEN OF MAGENDIE

POSTERIOR OCCIPITAL HORN OF LV--> IS CHOROID PLEXUS PRESENT?

NO

WHAT FOLLOWS THE CONTOUS OF THE BRAIN?

PIA

CISTERNS OF SUBARACHNOID SPACE

POSTERIOR CEREBELLOMEDULLARY CISTERN/CISTERNA MAGNA PREPONTINE CISTERN INTERPEDUNCULAR CISTERN CHIASMATIC CISTERN CISTERN OF LAMINA TERMINALIS PRECALLOSAL CISTERN QUADRIGEMINAL CISTERN/CISTERN OF THE GREAT CEREBRAL V. AMBIENT CISTERN CISTERN OF THE LATERAL CEREBRAL FOSSA LATERAL CEREBELLOMEDULLARY CISTERN PONTOCEREBELLAR CISTERN

WHAT IS THE MOST VARIABLE PART OF THE LATERAL VENTRICLE?

POSTERIOR/OCCIPITAL HORN

WHAT CISTERN IS AN ALT SITE TO SAMPLE CSF (BUT YOU DON'T REALLY WANT TO ACTUALLY DO IT)

POSTERIOR/dorsal cerebellomedullary cistern (cistern magna)

THE APEX OF THE 4TH VENTRICLE PROJECTS...

POSTERIORLY TOWARD CEREBELLUM

WHAT SPACE IS FILLED WITH CSF?

SUBARACHNOID

SMV

SUPERIOR/ANTERIOR MEDULLARY VELUM THIN WHITE MATTER SHEET BETWEEN SUPERIOR CEREBELLAR PEDUNCLES CONTINUOUS W/ CEREBELLAR WHITE MATTER

THE 4TH V IS CONTINUOUS

SUPERIORLY WITH CEREBRAL AQUEDUCT INFERIORLY WITH CENTRAL CANAL OF SP. CORD

4 RECESSES OF THE 3RD VENTRICLE

SUPRAOPTIC INFUNDIBULAR PINEAL SUPRAPINEAL

BRAIN

VENTRICULAR SYSTEM

THE CEREBRAL AQUEDUCT IS LOCATED WHERE?

WITHIN MIDBRAIN CONNECTS 3RD AND 4TH VENTRICLES NO CHOROID PLEXUS

the anterior continuation of the quadrigeminal cistern

ambient cistern between midbrain and medial part of temporal lobe

small amounts of CSF pass between what?

between cells covering the arachnoid granulations most CSF is tported through these cells in membrane-bound vesicles

Important things about the posterior cerebellomedullary cistern

between post surface of medulla and inf surface of cerebellum median aperture of 4th v opens into it alternate site to sample CSF (cisternal puncture)

non-communicating hydrocephalus

caused by obstruction of CSF flow within ventricular system (cerebral aqueduct or IV foramen) from the ventricles to the subarachnoid space ventricles enlarge PROXIMAL to the obstruction

communicating hydrocephalus

caused by: -impaired CSF reabsorption in the arachnoid granulations -obstruction in the subarachnoid space -excess CSF production (rare)

What is the villous structure that extends from ventricular surface (like coral fronds) into the CSF

choroid plexus

The quadrigeminal cistern

cistern of the great cerebral v. between spleium of corpus callosum and superior cerebellar surface, posterior to the midbrain tectum *THE GREAT CEREBRAL V. FORMS AND CROSSES HERE!*

CSF

clear, colorless

the villi of the choroid plexus consist of

core of highly vascularized CT (derived from Pia) covering of simple cuboidal ep-->choroidal epithelial cell layer (derived from ependyma)

normal pressure hydrocephalus is present with the typical triad

gait distubance urinary incontinence mendtal decline *CSF pressure is usually NOT elevated, thought to wax and wane over time

Dilation of 1+ parts of the ventricular system due to abnormal accumulation of CSF

hydrocephalus

reabsorption of CSF depends on

hydrostatic P of CSF being greater than venous blood in the dural sinuses

normal pressure hydrocephalus

in elderly chronically dilated ventricles

What cistern surrounds CNs 9, 10, 11, and 12?

lateral cerebellomedullary cistern -->located lateral to upper medulla *the lateral aperture of the 4th v opens into it

Where is CSF made?

made by choroid plexus in the lateral, 3rd, and 4th ventricles

flow of CSF

made by choroid plexus in ventricles passes through lateral and median aperture of 4th ventricle -->subarachnoid space-->reabsorbed in venous system by arachnoid granulations/villi @ the superior saggital sinus

normal pressure hydrocephalus

mech is not known thought to be a form of communicating hydrocephalus with impaired reabsorption @ the arachnoid granulations

what cistern surrounds CNs 5, 7, and 8

pontocerebellar cistern -located @ jn of pons and cerebellum (pontocerbellar angle)

arachnoid granulations

projections of arachnoid through the dural wall into the lumen of the superior saggital sinus

Tx of normal pressure hydrocephalus

shunting procedure to reduce CSF pressure and volume 30-50% of pts improve