08 26 2014 Meninges and Ventricals Flashcards Preview

Neurology 1- M2 > 08 26 2014 Meninges and Ventricals > Flashcards

Flashcards in 08 26 2014 Meninges and Ventricals Deck (37):
1

Cerebral Spinal fluid

Clear, colorless liquid
140mL
Provides buoyancy, and protects against sudden movements.

Some antibacterial properties

2

Cisterns

Enlarged areas of subarachnoid space (around brain stem)
-Perimesencephalic cisterns
-Prepontine cistern
-cisterna magna

3

perimesencephalic cisterns

Interpeduncular cistern (ventral and abovepons)

Quadrigeminal (and ambient) cisterns (between corpus collusum and cerebellum and pons)

4

Prepontine cistern

ventral to pons (aka in front of pons)

5

Cisterna magna

below cerebellum

6

Why do you use a lumbar puncture?

Diagnose subarachnoid hemorrhage and meningitis or introduce drugs.

Adults: L3-L4
Children: L4-L5

7

What is normal pressure of CSF

< 20 cm H2O

8

Layers of Dura in Brain vs. spinal cord?

Brain: 2 layers
-periosteal and meningeal -- split to form sinuses

Spinal cord : 1 layer -- meningeal (vertebrae have their own periosteum)

9

Layers of Arachnoid in brain vs. spinal cord?

Brain: arachnoid trabecular and many cisterns

Spinal cord: fewer travecule and 1 cistern (lumbar cistern)
- this is where you do lumbar puncture

10

Layers of Pia in brain vs. spinal cord?

Spinal cord: forms denticulate ligaments and filum terminal

11

Denticulate Ligament of spinal cord?

anchor pia to dura (from pia to dura)

12

Filum Terminum of spinal cord?

anchors spinal cord to arachnoid.

13

Coccygeal ligament (filum terminale externum) of spinal cord?

anchors spinal cord to coccyx

14

What are the dural folds?

(just name them)

Invaginations of inner dural layer. Create the supratentorial and infratentorial spaces (in reference to tentorium)

1. Flax cerebri
2. Falx cerebelli
3. Tentorium cerebelli
4. Diaphragm sellae

15

Falx cerebri

in between cerebral hemispheres (in longitudinal fissure)

16

Falx cerebelli

separates cerebellum in right vs. left

17

Tentorium cerebelli

lies between the posterior cerebral hemispheres and the cerebellum

18

Diaphragm sellae

circular fold beneath the brain that covers the sella turcica.

19

posterior fossa

the cavity formed with occipital bone as base and tentorium cerebella as roof.

Contains cerebellum and brainstem

20

tentorial notch

hole within dural folds where the brainstem can go through

21

Flow of CSF

lateral ventricles --- foramen of Monro--> third ventricle (diencephalon) -- cerebral aqueduct (midbrain) --> 4th ventricle in pons/medulla--- foramen of Magendie and Luschka --> subarachnoid space around brian and spinal cord ---> arachnoid granulations ---> veinous sinuses

22

Blood - CSF barrier

choroidal capillaries are fenestrated with no tight junctions BUT choroid epithelium (ependymal cells w/tight junctions) has the tight junctions. Therefore the choroid epithelium form the blood-CSF barrier

23

hydrocephales

increase volume of CSF

1. overproduction (rare)
2. Obstruction of flow
3. decrease reabsorption via arachnoid granules

May be chronic in children

24

Communicating hydrocephalus

blockage of CSF reabsorption in arachnoid granules OR obstruction of flow in the subarachnoid space

25

Noncommunicating hydrocephalus

obstruction of flow within ventricular system

26

Symptoms of increased intracranial pressure

1. headache
2. Nausea and vomitting
3. 6th Nerve palsy
-eyes appear to look downwards
4. papilledema (swelling of optic papilla)
5. Decreased vision/ diplopia (double vision)
6. Decreased cognition
7. Unsteady gait
8. Cushing's triad: hypertension, bradycardia, and irregular respirations (brainstem)

27

Blood brain barrier

formed by tight junctions of epithelium on capillary. The BBB may be disrupted by infections, tumor or trauma and can cause "vasogenic edema"
- shows up as breakdown of epithelium.

28

Circumventricular organs

parts in which the BBB is interrupted. It enables the brain to resound to changes in the blood chemistry

- Area postrema: detecting circulating toxins that cause vomiting

29

Epidural Hematoma

Potential space

caused by trauma (fracture of the temporal bone) that lesions middle meningeal artery.

Rapidly expanding hemorrhage
Lens- biconvex shape

Increase in pressure causes a herniation

30

Subdural hematoma

Potential space

rupture of bridging veins due to a high velocity impact. (acute)

Can be a chronic condition in elderly (brain shrinks which puts them at an increased risk of tearing a bridging vein.

Cresent shape

31

Subarachnoid hematoma

Real space -- has blood vessels

1. Non-traumatic
-WORST HEADACHE OF MY LIFE
- aneurysms or Arteriovenus malformations

2. Traumatic
-bleeding into CSF from damaged blood vessels associated with cerebral contusions and other traumatic brain injuries

32

What are the two types of Aneurysms?

1. Saccular/ Berry:
-balloon like

2. Fusiform
-main vessel itself becomes dilated (less likely to rupture and thereofer more likely to compress something)
- Posterior communicating arter --> 3rd Nerve
palsy

33

where do aneurysms mostly occur? (Saccular)

1. Anterior communicating artery (30%)
2. Posterior communicating artery (25%)
3. Middle cerebral artery (20%)
4. Posterior circulation (15%)

34

Transtentonial Herniation and symptoms

Uncal herniation -- medial temporal lobe herniates through tenurial notch.

1. blown pupil -- ipsilateral dilated, unresponsive pupil (CN 3)

2. Hemiplegia: paralysis of half of the body

3. coma

4. posterior cerebral arteries may be compressed -- infarction in posterior cerebral artery territory.

35

Central herniation

central downward displacement of the brainstem.

Mild herniation = traction on abducen's nerve = lateral rectus (unilateral or bilateral)

36

Tonsillar herniation

Cerebellar tonsils move downward through foramen magnum.
- compression of medulla
-leads to respiratory arrest, blood pressure instability and death

37

Subfalcine herniation

unilateral mass lesions that cause cingulate gyrus (and other structures) to herniate under the flax cerebra from one side of the cranium to the other.

- may be symptomatic
-may have symptoms of increased cranial pressure