5 MAGNETIC RESONANCE IMAGING OF THE VENTRICLES: AXIAL AND CORONAL VIEWS

Ventricles and the Cerebrospinal Fluid



73



Choroid plexus of lateral ventricle



Bridging veins



Superior sagittal sinus

Subarachnoid space



Supracallosal cistern

Dura mater



Arachnoid granulations



Arachnoid



Chiasmatic cistern

Choroid plexus of 3rd ventricle

Interpeduncular cistern

Cerebral aqueduct (of Sylvius)

Prepontine cistern

Lateral aperture (foramen of Luschka)

Choroid plexus of 4th ventricle

Dura mater

Arachnoid

Subarachnoid space



6.6╇CIRCULATION OF THE CEREBROSPINAL

FLUID

CSF flows internally through the ventricles, from lateral ventricles to the third ventricle to the cerebral aqueduct to the

fourth ventricle. The CSF passes through several points where

blockage or obstruction could precipitate internal hydrocephalus and increased intracranial pressure. CSF flow from the

fourth ventricle into the cisterns of the subarachnoid space,

surrounding the brain and spinal cord, provides the external

protective cushioning and buoyancy to protect underlying

central nervous system tissue from minor trauma. Some cisterns such as the lumbar cistern provide sites for �withdrawal



Cistern of great cerebral vein

Cerebellomedullary cistern (cisterna magna)

Median aperture (foramen of Magendie)



of CSF (lumbar puncture). The CSF is absorbed from the

�subarachnoid space into the venous drainage through the

arachnoid granulations by a process driven by the pressure of

flow through these one-way valves. Disruption of this drainage results in external hydrocephalus. Thus, production, flow,

and absorption of CSF must be in precise balance. The flow

of the CSF in the ventricles also can act as a fluid-delivery

system for downstream influences of specific mediators (e.g.,

prostaglandins, interleukins) and represents an internal paracrine communication channel for some structures close to the

�ventricles.



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7





VASCULATURE



Arterial System



7.1

7.2

7.3

7.4



Meningeal Arteries: Relationship to Skull and Dura

Arterial Supply to the Brain and Meninges

Internal Carotid and Ophthalmic Artery Course

Arterial Distribution to the Brain: Basal View



7.5



Arterial Distribution to the Brain: Cutaway Basal

View Showing the Circle

of Willis

Arterial Distribution to the Brain: Frontal View with

Hemispheres Retracted

Arterial Distribution to the Brain: Coronal Forebrain

Section

Types of Strokes

S

 chematic of Arteries to the Brain

Circle of Willis: Schematic Illustration and Vessels in

Situ

Arterial Distribution to the Brain: Lateral and Medial

Views

Color Illustration of Territories of the Cerebral

�Arteries

Magnetic Resonance Angiography: Frontal and

Lateral Views

Angiographic Anatomy of the Internal Carotid

�Circulation

Vertebrobasilar Arterial System



7.6

7.7

7.8

7.9

7.10

7.11

7.12

7.13

7.14

7.15



7.16

7.17

7.18

7.19

7.20



A

 ngiographic Anatomy of the Vertebrobasilar

�System

V

 ascular Supply to the Hypothalamus and the

�Pituitary Gland

A

 rterial Blood Supply to the Spinal Cord:

�Longitudinal View

A

 nterior and Posterior Spinal Arteries and Their

Distribution

A

 rterial Supply to the Spinal Cord: Cross Sectional

View







Venous System



7.21

7.22



M

 eninges and Superficial Cerebral Veins

V

 eins: Superficial Cerebral, Meningeal, Diploic, and

Emissary

V

 enous Sinuses

D

 eep Venous Drainage of the Brain

D

 eep Venous Drainage of the Brain: Relationship to

the Ventricles

C

 arotid Venograms: Venous Phase

M

 agnetic Resonance Venography: Coronal and

Sagittal Views

V

 enous Drainage of the Brain Stem and the

�Cerebellum

Venous Drainage of the Spinal Cord



7.23

7.24

7.25

7.26

7.27

7.28

7.29



75



76



Overview of the Nervous System



Arachnoid granulations

Parietal (posterior) and frontal (anterior)

branches of middle meningeal artery



Opening of superior

cerebral vein

Venous lacuna



Middle meningeal artery



Superior

sagittal sinus

Dura mater



Anterior meningeal artery (from

anterior ethmoidal artery)



Mastoid branch

of occipital artery



Anterior and posterior meningeal

branches of vertebral artery

Mastoid branch

of occipital artery



Meningeal branches of ascending pharyngeal artery

Tentorial branch (cut) and dorsal meningeal

branch of meningohypophyseal trunk

Middle and accessory meningeal arteries

Meningeal branch of posterior ethmoidal artery

Anterior meningeal artery (from anterior ethmoidal artery)

Internal carotid artery and its meningohypophyseal trunk (in phantom)

Middle meningeal artery

Accessory meningeal artery

Superficial temporal artery

Maxillary artery

Posterior auricular artery

Occipital artery

External carotid artery



arterial system

7.1  MENINGEAL ARTERIES: RELATIONSHIP

TO SKULL AND DURA

Meningeal arteries are found in the outer portion of the dura;

they supply it with blood. They also help to supply blood to adjacent skull and have some anastomoses with cerebral arteries.

The skull has grooves, or sulci, for the meningeal vessels. This

relationship reflects an important functional �consequence of



skull fractures. Fractures can rip a meningeal artery (­usually

the middle meningeal artery) and allow arterial blood to

�accumulate above the dura. Such an epidural hematoma is a

space-occupying mass and can produce increased intracranial pressure and risk for herniation of the brain, particularly

across the free edge of the tentorium cerebelli. Even very fine

fractures can have this dangerous consequence.



Vasculature



77



Left middle meningeal artery



Right and Ieft middle cerebral arteries



Right and Ieft posterior

cerebral arteries



Right and Ieft anterior cerebral arteries

Anterior communicating artery



Right and Ieft superior

cerebellar arteries



Right ophthalmic artery

Right posterior

communicating artery



Basilar artery



Cavernous sinus



Mastoid branch of

Ieft occipital artery

Left interior auditory

(labyrinthine) artery



Right deep temporal artery



Posterior meningeal branch

of Ieft ascending

pharyngeal artery



Right maxillary artery

Right middle meningeal artery



Right and Ieft anterior

inferior cerebellar arteries



Right superficial temporal artery



Right and Ieft posterior

inferior cerebellar arteries



Right exterior carotid artery



Posterior meningeal branches

of right and Ieft vertebral arteries

Anterior meningeal branch

of right vertebral artery

Right posterior auricular artery

Right occipital artery

Right interior carotid artery

Right ascending pharyngeal artery

Right carotid sinus



Right facial artery

Right lingual artery

Carotid body

Right superior laryngeal artery

Right superior thyroid artery

Thyroid cartilage

Right common carotid artery



Right vertebral artery



Right inferior thyroid artery



Transverse process of C6



Right interior thoracic artery



Right deep cervical artery

Right thyrocervical trunk



Brachiocephalic trunk



Right costocervical trunk

Right subclavian artery



7.2  ARTERIAL SUPPLY TO THE BRAIN

AND �MENINGES

The internal carotid artery )>>ICA) and the vertebral artery ascend through the neck and enter the skull to supply the brain

with blood. The tortuous bends and sites of branching )>>such

as the bifurcation of the common carotid artery into the internal and external carotids) produce turbulence of blood flow

and are sites where atherosclerosis can occur. The bifurcation

of the common carotid is particularly vulnerable to plaque

formation and occlusion, threatening the major anterior part

of the brain with ischemia, which would result in a stroke. The

ICA passes through the cavernous sinus, a site where carotidcavernous fistulae can occur, resulting in damage to the extraocular and trigeminal cranial nerves, which also pass through

this sinus. Studies of blood flow through these arteries are important diagnostic tools. Magnetic resonance arteriography

and Doppler flow studies have, for most purposes, replaced

the older dye studies for performing cerebral angiography.



CLINICAL POINT

The paired carotid arteries and vertebral arteries supply the brain and

part of the spinal cord with blood. The carotids supply the anterior

circulation, including most of the forebrain except for the occipital

lobe and inferior surface of the temporal lobe. The bifurcation of

the common carotid artery is a common site of plaque formation in

atherosclerosis, leading to gradual occlusion of blood flow to the forebrain on the ipsilateral side. Early warnings can be seen in the form of

transient ischemic attacks, forerunners of a full-blown stroke. The best

treatment is prevention, with exercise, proper diet and weight control,

careful regulation of lipid levels and other contributing factors such as

inflammatory mediators. In cases in which severe and symptomatic

occlusion has occurred as the result of atherosclerotic plaque, carotid

endarterectomy can be performed to remove the plaque and attempt

to open up more robust flow to the anterior circulation. Carefully

performed controlled studies have established criteria that determine

which patients can best benefit from this surgical procedure as opposed to more conservative medical treatment. Current studies are

investigating the use of carotid stents to enhance blood flow to the

brain.