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