Meninges, Ventricles, and CSF

Question 1

What are the three meningeal layers?

Answer 1

Dura

Arachnoid

Pia

Question 2

What is the cranial dura?

Answer 2

Composed of two layers - outer most essentially serves as periosteum and is not continuous with the the dura of the spinal cord

Inner layer is fused with the endosteal layer except where it forms the septa

Question 3

What is the function of the dural septa?

Answer 3

Provide support and protection for the brain

Protects the brain against sudden and violent movements of the head

Question 4

What is the Falx Cerebri?

Answer 4

Longitudinal Septum in the sagittal fissure between the two cerebral hemispheres

Question 5

What is the tentorium cerebelli?

Answer 5

Septum that extends horizontally between the occipital lobes and the cerebellum attached to the falx cerebri

Forms roof over the posterior cranial fossa

Question 6

Between what layers are the dural venous sinuses located?

Answer 6

Between endosteal and meningeal layers or between two meningeal layers

Question 7

Where is the superior sagittal sinus?

Answer 7

Within the attached borders of the falx cerebri

Receives branches from the superior cerebral veins

Major area where CSF return to the general systemic circulation

Question 8

Where is the inferior sagittal sinus?

Answer 8

Extends along the inferior free margin of the falx cerebri

Question 9

What is the Great Cerebral Vein of Galen?

Answer 9

Collects venous blood from internal cerebral veins, joins the inferior sagittal sinus to form the straight sinus

Question 10

What lies within the subarachnoid space?

Answer 10

Trabeculae (fibrous filaments) that bridge the arachnoid and pial membranes

CSF

All major blood vessels of the brain

Question 11

Where is the cerebellomedullary cistern?

Answer 11

Spans the space over the cerebellum and the part of the brainstem called the medulla

Question 12

Where is the pontine cistern?

Answer 12

Lies over the pons

Question 13

Where is the interpeduncular cistern?

Answer 13

Lies over the interpeduncular fossa (ventral brain surface)

Circle of willis lies within this cistern

Question 14

Where is the lumbar cistern?

Answer 14

Extends from vertebral levels L1/L2 to S2

Area where spinal taps are done

Question 15

What are arachnoid villi?

Answer 15

Structures which allow for passage of CSF from the subarachnoid space into the superior sagittal sinus back to the general circulation

Question 16

What is the pia mater?

Answer 16

thin, highly vascularized membran that adhers closely to the surface of the brain and spinal cord

Question 17

What are Virchow-Robin spaces?

Answer 17

Subarachnoid space around anastomosing vessels within the brain before the major branches pass into the brain substance

Question 18

What is papilledema?

Answer 18

Edema of the optic papilla caused by elevated CSF pressure around the optic nerve

Question 19

Describe the lateral ventricles.

Answer 19

The two larges ventricles, one in each hemisphere

Each ventricle has extensions called horns, named after the lobes or direction they extend

Question 20

What connects the lateral ventricles and the third ventricles?

Answer 20

Intraventricular foramen of Monro

Question 21

What forms the walls of the third ventricle?

Answer 21

Thalamus and Hypothalamus

Question 22

What connects the third and fourth ventricles?

Answer 22

Aqueduct of sylvius

Question 23

What structures form the fourth ventricle?

Answer 23

The roof is formed by the cerebellum and its floor by the pons and medulla

Question 24

How does CSF enter the subarachnoid space from the 4th ventricle?

Answer 24

Through two lateral foramina of Luschka

And a medial foramen of Magendie

Question 25

What is the function and location of the Pineal Body?

Answer 25

Outside the BBB

Secretes melatonin, important for circadian rhythms

Question 26

What is the function of the Organum vasculosum of the lamina terminalis?

Answer 26

Sensory area that supplies input to other brain regions

Contains osmoreceptors sensitive to Na and osmotic pressure in blood

Question 27

What is the function of the median eminence of the hypothalamus?

Answer 27

Secretes hormones

CRF, TRH, GnRH, GHRH

Question 28

What is the function of the subcommissural organ?

Answer 28

Produces transthyretin

Question 29

What is the function of the neurohypophysis?

Answer 29

Endocrine organ

Produces oxytocin, vasopressin

Question 30

What is the function of the Area Postrema?

Answer 30

Chemoreceptor trigger zone (vomit center)

Question 31

Where is CSF found?

Answer 31

Ventricles, Subarachnoid space and cisterns

Interstitial space in the brain

Continuously produced, but only a small amount of CSF is in the ventricles at any one time

Question 32

What does pink or red CSF indicate?

Answer 32

Blood in the CSF

Most commonly due to leakage/rupture of an aneurysm in CoW

Question 33

What does yellow and spontaneous clotting CSF indicate?

Answer 33

Increased protein content or from lysis of RBC

Increased IgG can indicate a chronic inflammatory process within the CSF

Question 34

What does cloudy or white CSF indicate?

Answer 34

Bacterial meningitis

Elevated WBCs

Question 35

What does clear to slightly cloudy CSF indicate?

Answer 35

May indicate aseptic meningitis

Elevated WBCs

Commonly associated with a viral infection

Question 36

What causes the circulation of the CSF?

Answer 36

Arterial pulsations

Respiratory movements

Vasomotor activity

All move towards the superior sagittal sinus